Use of Access Unit Delimiters and Adaptation Parameter Sets

Abstract

To provide a method of obtaining a reconstructed version of a decoded picture and to provide a video decoder.SOLUTION: A video decoder is provided, comprising: an in-loop filter configured to filter a reconstructed version of a decoded picture; and a parametrizer configured to parametrize the in-loop filter by reading in-loop filter control information for parametrizing the in-loop filter from parameter sets located within the access unit AU of the decoded picture which follow, along data stream order, video coding units, and / or a portion of the video coding units following, along data stream order, data comprised by the video coding units, which carries block-based prediction parameter data and prediction residual data, and configured to parametrize the in-loop filter so as to filter the reconstructed version of the decoded picture in a manner depending on the in-loop filter control information.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] This application relates to the use of access delimiters and adaptation parameter sets for signaling coding parameters. [Background technology]

[0002] Modern video coding standards utilize in-loop filters such as adaptive loop filters (ALF), sample adaptive offset (SAO) and deblocking filters.

[0003] The in-loop filters are placed in the decoding loop of the encoder. During all video encoding stages, and especially in the lossy compression performed at the quantization stage, the subjective quality of a video sequence may be reduced as a result of the appearance of blocking, ringing or blurring artifacts. To remove these artifacts and improve the subjective and objective quality of the reconstructed sequence, a set of in-loop filters is used. The in-loop filters in the encoder estimate the optimal filter parameters that best improve the objective quality of the frame. These parameters are then transmitted to the decoder, where the in-loop filters can use these parameters to optimally filter the reconstructed frame and achieve the same quality improvement as achieved for the reconstructed frame in the encoder.

[0004] The deblocking filter aims to remove blocking artifacts that appear at the edges of CUs (coding units), specifically PUs (prediction units) and TUs (transform units), as a result of the use of a block structure in the processing at all stages of the encoder.

[0005] The SAO filter aims to reduce undesirable visible artifacts such as ringing. The key idea of ​​SAO is to reduce sample distortion by first classifying the reconstructed samples into different categories, obtaining an offset for each category, and then adding the offset to each sample in the category.

[0006] The key idea of ​​ALF is to minimize the mean squared error between original and decoded pixels using Wiener-based adaptive filter coefficients. ALF can be seen as a tool placed at the last processing stage of each picture, which tries to catch and correct artifacts from the previous stage. The appropriate filter coefficients are determined by the encoder and explicitly signaled to the decoder. That is, ALF requires a set of parameters to be sent to the decoder, i.e., the appropriate filter coefficients. These parameters are transmitted in a high-level syntax structure, e.g., the Adaptation Parameter Set (APS). APS is a parameter set transmitted in the bitstream before the Video Coding Layer (VCL) NAL (Network Abstraction Layer) units, i.e., slices of a picture. ALF is applied to the complete picture after reconstruction. Also, at the encoder, ALF estimation is one of the last steps of the encoding process.

[0007] In low-delay environments, this creates problems, since the encoder wants to start transmitting the processed parts of a picture as soon as possible, especially before finishing the encoding process of the picture. The ALF cannot be used optimally in these environments, since the APS with the estimated filter parameters for the encoded picture must be transmitted before the first slice of the picture.

[0008] Furthermore, a set of NAL units of a specified format is called an access unit, AU, and the decoding of each AU results in one decoded picture. Each AU contains a set of VCL NAL units that together make up a primary coded picture. It may also be prepended with an access unit delimiter (AUD) to help identify the start position of the AU.

[0009] AUDs are used to separate AUs in the bitstream and can optionally contain information about the following picture, such as the allowed slice types (I, P, B).

[0010] In Versatile Video Coding (VVC), a picture can reference several different parameter sets: a video parameter set (VPS), a decoder parameter set (DPS), a sequence parameter set (SPS), multiple picture parameter sets (PPS), different types of adaptation parameter sets (APS), and / or one or more of these. A decoder needs to have all the parameter sets to be able to decode a picture.

[0011] Different slices of a picture can reference different PPSs and APSs, so it can be difficult for a decoder to determine if all required parameter sets are available, because it must parse all slice headers of the picture and decode which parameters are referenced. Summary of the Invention [Problem to be solved by the invention]

[0012] It is an object of the present subject matter to provide a decoder that derives the necessary parameters from the access units. [Means for solving the problem]

[0013] This object is achieved by the subject matter of the present claims.

[0014] According to an embodiment of the present application, the video decoder includes one or more video coding units (100) in an access unit AU of the video data stream, e.g. a decoding core (94) configured to reconstruct a decoded picture, e.g. a currently decoded picture or a subsequent decoded picture, using motion compensation prediction and transform-based residual decoding from a VCL NAL unit, e.g., a VCL NAL unit, to obtain a reconstructed version of a decoded picture (46a), an in-loop filter (90) including, e.g., an ALF, configured to filter the reconstructed version of the decoded picture (46b) to obtain a version of the decoded picture (46b) to be inserted into a decoded picture buffer DPB (92) of the video decoder, and a parameterizer, e.g., one or more parameter sets (102, 104) located in the access unit AU of the decoded picture, e.g., an ALF per CTU APS, following one or more video coding units (100) along the data stream order, e.g., individually with VCL NALUs or following all of them. and a parameterizer configured to parameterize the in-loop filter by reading in-loop filter control information, e.g., ALF coefficients (or parameters) and ALF per CTU (coding tree unit) flags, for parameterizing the in-loop filter from the APS and ALF and / or the data (108) included in the one or more video coding units (100) that carry block-based prediction parameter data and prediction residual data along the data stream order, e.g., ALF per CTU data, and parameterizing the in-loop filter to filter a reconstructed version of the decoded picture in a manner according to the in-loop filter control information. That is, the in-loop filter control information is derived for one or more video coding units, and thus it is possible to start decoding before receiving all video coding units of a picture. Thus, the decoding delay is reduced in a low-delay environment.

[0015] According to an embodiment of the present application, the in-loop filter control information includes one or more filter coefficients for parameterizing the in-loop filter with respect to a transfer function, i.e., the ALF is, for example, a FIR (Finite Impulse Response) or IIR (Infinite Impulse Response) filter and the filter coefficients FIR or IIR coefficients that control the transfer function of the filter.

[0016] According to an embodiment of the present application, the in-loop filter control information includes spatially selective in-loop filter control information for spatially varying filtering of a decoded picture, e.g., a reconstructed version of a currently decoded picture or a subsequent decoded picture, by the in-loop filter.

[0017] According to an embodiment of the present application, each video coding unit (100) successively arithmetically codes the data along the data stream order until the end of the portion (106), i.e., until the ALF. A predetermined parameter set (102) of the one or more parameter sets follows each of the one or more video coding units (100) in the data stream order and comprises one or more filter coefficients for parameterizing an in-loop filter in terms of a transfer function.

[0018] According to an embodiment of the present application, the one or more parameter sets (104) include, for each of the one or more video encoding units (100), further predefined parameter sets following the respective video encoding units (100) in data stream order and including spatially selective in-loop filter control information for spatially varying filtering of a decoded picture, e.g., a reconstructed version of a currently decoded picture or a subsequent decoded picture, by an in-loop filter within a portion of a picture encoded in the respective video encoding unit (100).

[0019] According to an embodiment of the present application, each of the one or more video encoding units (100) includes a filter information section (106) following in data stream order in the data section (108) of the respective video encoding unit (100), the filter information section including spatially selective in-loop filter control information for spatially varying filtering of a decoded picture, e.g., a reconstructed version of a currently decoded picture or a subsequent decoded picture, by an in-loop filter within a portion of a picture in which block-based prediction parameter data and prediction residual data are encoded in the data section of the respective video encoding unit (100).

[0020] According to an embodiment of the present application, the parameterizer may be configured to place within the access unit (AU) the one or more parameter sets (102, 104) of the decoded picture, e.g. the current decoded picture or a subsequent decoded picture, e.g. the ALF APS and the ALF per CTU APS, in a position following the one or more video encoding units (100) along the data stream order, e.g. individually with a VCL NALU or following all of them, in case of a predetermined indication in the video data stream to assume a first state, and in a different position within the access unit preceding all of the one or more video encoding units (100) in case of the predetermined indication in the video data stream to assume a second state.

[0021] According to an embodiment of the present application, a portion (106) of one or more video encoding units (100), e.g., an ALF for each CTU data, is located in a position following data (108) constructed by the one or more video encoding units (100) along the data stream order, carrying block-based prediction parameter data and prediction residual data, in the case of a given instruction in the video data stream to assume a first state, and is located in a different position within the one or more video encoding units interspersed with the block-based prediction parameter data and prediction residual data, in the case of a given instruction in the video data stream to assume a second state.

[0022] According to an embodiment of the present application, the video decoder is configured to read a predetermined instruction from one or more video encoding units (100). The predetermined instruction indicates one or more parameter sets by one or more identifiers when a first state is assumed, and indicates one or more different in-loop filter control information parameter settings when a second state is assumed. The video decoder is configured to respond to the predetermined instruction for each access unit, such that, if the predetermined instruction is different for different access units, the video decoder performs different position determinations for different access units of the video data stream. The parameterizer is configured to reconstruct a decoded picture using the in-loop filter control information included in the previously signaled access unit AU.

[0023] According to an embodiment of the present application, the video decoder is configured, when detecting an access unit AU boundary, to interpret video coding units carrying in-loop filter control information, e.g., ALF filter data, in the form of one or more parameter sets (102, 104), e.g., a suffix APS, as not starting an access unit, and therefrom, e.g., to ignore them in the AU boundary detection, thereby detecting the absence of an AU boundary, and to interpret video coding units carrying in-loop filter control information that is not in the form of one or more parameter sets (102, 104), e.g., a suffix APS, as starting an access unit from such video coding units, and to detect an AU boundary from such video coding units.

[0024] According to an embodiment of the present application, a video decoder is configured to decode video from a video data stream by decoding a decoded picture, e.g., a currently decoded picture or a subsequent decoded picture, from one or more video encoding units (100) in an access unit AU of the video data stream in a parameterized manner using one or more predefined encoding parameters, derive predefined encoding parameters (122) from a plurality of parameter sets (120) scattered in the video data stream, and read an identifier (200) from a predefined unit (124) of the access unit AU, which identifies a predefined parameter set from a plurality of parameter sets including the predefined encoding parameters. That is, the presence or absence of an encoding parameter is indicated by the identifier, and thus it is efficiently known which parameter set can be derived from the received video encoding unit. Also, since the identifier is included in the predefined unit of the AU, it is easy to include different parameter sets for different video encoding units.

[0025] According to an embodiment of the present application, a given unit of an AU includes a flag (204) that indicates whether an identifier (200) is present in the given unit, i.e., the flag can indicate which identifier is included in the given unit of an AU, for example, the delimiter of an access unit.

[0026] According to an embodiment of the present application, the multiple parameter sets (120) are of different hierarchical levels, and one or more video coding units include, for example in a slice header, an identifier that references a first predefined parameter set (126) in one or more first predefined hierarchical levels, which in turn includes an identifier that references a second predefined parameter set (128) in one or more second predefined hierarchical levels, the first and second predefined parameter sets being included by the predefined parameter set (122). The identifier read from the predefined unit (124) of the access unit AU identifies all predefined parameter sets that are directly or indirectly referenced by one or more video coding units of the access unit, such that the access unit is decodable if all predefined parameter sets identified by the identifiers are available.

[0027] According to an embodiment of the present application, a given unit of an AU includes a flag (204) that indicates (205) whether a given identifier of a particular given parameter set (126b), e.g. an identifier (200) referencing a particular APS, is present in the given unit (124) or whether a given identifier referencing a particular given parameter set (126b) is present in one or more video encoding units (100).

[0028] According to an embodiment of the present application, the first predefined parameter set (126) includes a third predefined parameter set (126a) that is referenced by an identifier in one or more video encoding units (100), and a fourth predefined parameter set (126b) that is referenced by an identifier (200) present in the predefined unit (124), but not referenced by any of the identifiers in the one or more video encoding units (100) or by any of the predefined parameter sets.

[0029] According to an embodiment of the present application, a given unit of an AU comprises one or more of the following: one or more identifiers of one or more adaptation parameter sets, APS, one or more identifiers of one or more picture parameter sets, PPS, a video parameter set identifier, VPS, a decoder parameter set identifier, DPS, and one or more identifiers of one or more sequence parameter sets, SPS. The multiple parameter sets include a video parameter set, VPS, a decoder parameter set, DPS, a sequence parameter set, SPS, one or more picture parameter sets, PPS, and one or more adaptation parameter sets, APS.

[0030] According to an embodiment of the present application, a video decoder is configured to decode video from a video data stream by decoding pictures from one or more video coding units (100) of an access unit (AU) of the video data stream, and to read one or more parameters from an access unit delimiter AUD located in the video data stream to form a start of an access unit AU, the one or more parameters controlling whether a separate access unit is defined in the video data stream for pictures related to one instant of the video data stream but different layers, or whether a picture related to one instant of the video data stream but different layers is encoded in one of the access units (300); and / or indicating a coding type of a video coding unit included in an access unit that is assigned to a video coding unit in one access unit (302), if the indication of the video coding type includes different video coding units from each other within one access unit; and / or indicating pictures that the access unit is not referenced by other pictures (304); and / or indicating pictures that are not output (306). That is, since the parameters required for decoding a picture are indicated by the AUD, it is possible to start decoding slices of a picture included in an AU before obtaining all parameter sets for decoding the complete picture. That is, since the parameter set required for each slice can be efficiently indicated by the AUD, it is possible to improve the decoding speed.

[0031] According to an embodiment of the present application, the one or more parameters form a deviation to the parameters defined by a previous AUD. The AUD includes an indication of whether the parameters defined by the previous AUD should be adopted. The AUD includes an indication of whether the one or more parameters apply to all layers of the video data stream or only to that single layer. The video coding type of the video coding unit is indicated by describing the random access characteristics of the multiple pictures.

[0032] According to an embodiment of the present application, a video decoder is configured to decode video from a video data stream by decoding pictures from one or more video coding units (100) of an access unit (AU) of the video data stream, and to read one or more parameters (308) from an access unit delimiter (AUD) located in the data stream to form the start of the access unit (AU), the one or more parameters indicating characteristics of the access unit and whether the characteristics apply to all layers of the video data stream or only to that single layer.

[0033] According to an embodiment of the present application, the method includes: reconstructing a decoded picture using motion compensated prediction and transform based residual decoding from one or more video encoding units (100) in an access unit AU of a video data stream, e.g., a VCL NAL unit, to obtain a reconstructed version of a decoded picture; filtering the reconstructed version of the decoded picture using an in-loop filter to obtain a version of the decoded picture to be inserted into a decoded picture buffer DPB of a video decoder; filtering the reconstructed version of the decoded picture by the in-loop filter to obtain a version of the decoded picture to be inserted into a decoded picture buffer DPB of a video decoder; and parameterizing the in-loop filter, where parameterizing the in-loop filter includes one or more parameter sets (102, 104), e.g., ALF APS and CTU, located in said access unit AU of a decoded picture subsequent to the one or more video encoding units (100) along the data stream order. In one embodiment, the method includes: reading in-loop filter control information for parameterizing an in-loop filter from an ALF per APS and / or a portion (106) of one or more video encoding units (100) subsequent to data (108) included in the one or more video encoding units (100) carrying block-based prediction parameter data and prediction residual data along a data stream order, e.g., an ALF per CTU data, and filtering the reconstructed version of the decoded picture in a manner responsive to the in-loop filter control information.

[0034] According to an embodiment of the present application, a method is provided that includes decoding video from a video data stream by decoding a decoded picture, e.g. a currently decoded picture or a subsequent decoded picture, from one or more video encoding units (100) in an access unit AU of the video data stream in a parameterized manner with one or more predefined encoding parameters, deriving the predefined encoding parameters from a plurality of parameter sets scattered in the video data stream, and reading an identifier (200) from a predefined unit of the access unit AU that identifies the predefined parameter set from the plurality of parameter sets including the predefined encoding parameters.

[0035] According to an embodiment of the present application, a method is provided, comprising recovering video from a video data stream by decoding pictures from one or more video coding units (100) of an access unit AU of the video data stream, and reading one or more parameters from an access unit delimiter AUD located in the video data stream to form a start of an access unit AU, where the one or more parameters control whether separate access units are defined in the video data stream for pictures related to one instance of the video data stream but different layers, or whether pictures related to one instance of the video data stream but different layers are encoded in one of the access units (300), and where, if the indication of the video coding type includes different video coding units within one access unit, the coding type of the video coding units included within the access unit assigned to the video coding units within the one access unit (302), and / or the access unit indicates pictures that are not referenced by other pictures (304), and / or indicates pictures that are not output (306).

[0036] According to an embodiment of the present application, a method is provided that decodes video from a video data stream by decoding pictures from one or more video coding units (100) of an access unit (AU) of the video data stream, and reading one or more parameters (308) from an access unit delimiter (AUD) located in the data stream to form the start of the access unit (AU), the one or more parameters indicating characteristics of the access unit (AU), and whether the characteristics apply to all layers of the video data stream or only to that single layer. [Brief description of the drawings]

[0037] Preferred embodiments of the present application will now be described with reference to the drawings. [Figure 1] 1 shows a block diagram of an apparatus for predictive coding of video, as an example of a video encoder capable of encoding a layered video data stream according to embodiments of the present application. [Diagram 2] As an example of a video decoder capable of decoding a layered video data stream according to an embodiment of the present application, a block diagram of an apparatus for predictive decoding of video, compatible with the apparatus of FIG. 1, is shown. [Diagram 3] 1A and 1B are schematic diagrams showing an example of the relationship between a prediction residual signal, a prediction signal, and a reconstructed signal, respectively, to show the possibility of setting subdivisions for defining a prediction signal, handling a prediction residual signal, etc. [Figure 4] 1 shows a schematic diagram of an example of an encoding process according to the prior art; [Diagram 5] 2 shows a schematic diagram of an example of an encoding process for signaling pictures to a decoder according to an embodiment of the present application; [Figure 6a] 2 shows a schematic diagram of an example of an access unit AU according to an embodiment of the present application; [Figure 6b] 2 shows a schematic diagram of an example of an access unit AU according to an embodiment of the present application; [Figure 7] 1 illustrates a schematic diagram of another example AU according to an embodiment of the present application. [Figure 8] A figure showing an example of information regarding a parameter set identifier ID included in an access unit delimiter AUD according to an embodiment of the present application. [Figure 9] FIG. 13 is a diagram illustrating an example of information regarding a predetermined parameter set included in an AUD according to an embodiment of the present application. [Figure 10] FIG. 13 is a diagram illustrating an example of information regarding a predetermined parameter set included in an AUD according to an embodiment of the present application. [Figure 11a] 2 shows an example schematic diagram illustrating relationships between predefined coding parameter sets according to an embodiment of the present application; [Figure 11b] FIG. 2 shows a schematic diagram of an example illustrating which part of an AU indicates which identifier of which parameter set according to an embodiment of the present application. [Figure 11c] FIG. 13 shows a schematic diagram of another example of which part of an AU indicates which identifier of which parameter set according to an embodiment of the present application; [Figure 12a] FIG. 2 illustrates an example of parameters included in an AUD according to an embodiment of the present application. [Figure 12b] FIG. 2 illustrates an example of parameters included in an AUD according to an embodiment of the present application. [Figure 13] FIG. 13 is a diagram illustrating another example of parameters included in an AUD according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] In the following description, elements that are the same or equivalent, or have the same or equivalent functionality, are designated by the same or equivalent reference signs.

[0039] In the following description, a number of details are set forth to provide a more complete description of the embodiments of the present application. However, it will be apparent to those skilled in the art that the embodiments of the present application may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form, rather than in detail, to avoid obscuring the embodiments of the present application. In addition, unless otherwise noted, features of different embodiments described below may be combined.

[0040] Introduction It should be noted below that the individual aspects described herein may be used individually or in combination, and thus details may be added to each of the individual aspects without adding details to any other one of the aspects.

[0041] Also, note that this disclosure explicitly or implicitly describes features that can be used in a video decoder (an apparatus for providing a decoded representation of a video signal based on an encoded representation). Thus, any of the features described herein can be used in the context of a video decoder.

[0042] Moreover, features and functionality disclosed herein in relation to a method may also be used in an apparatus (configured to perform such functionality). Moreover, any features and functionality disclosed herein in relation to an apparatus may also be used in a corresponding method. In other words, the methods disclosed herein may be supplemented by any of the features and functionality described in relation to an apparatus.

[0043] The following description of the figures begins with a description of a video encoder and a video decoder of a block-based predictive codec for encoding pictures of a video to form an example of an encoding framework into which embodiments for a layered video data stream codec can be incorporated. The video encoder and the video decoder are described in relation to Figures 1-3. Below, a description of embodiments of the layered video data stream codec concepts of the present application is presented together with an explanation of how such concepts can be incorporated into the video encoder and decoder of Figures 1 and 2, respectively, although the embodiments described below can also be used to form video encoders and video decoders that do not operate according to the encoding framework underlying the video encoder and video decoder of Figures 1 and 2.

[0044] Figure 1 shows a block diagram of an apparatus for predictive coding of video as an example of a video decoder capable of implementing motion compensated prediction of inter-predicted blocks according to an embodiment of the present application. That is, it shows an apparatus for predictively coding a video 11 consisting of a sequence of pictures 12 into a data stream 14. For this purpose, block-based predictive coding is used. Furthermore, transform-based residual coding is exemplarily used. The apparatus, i.e. the encoder, is indicated with the reference number 10.

[0045] Fig. 2 shows a block diagram of an apparatus for predictively decoding a video as an example of a video decoder capable of performing motion compensation prediction of an inter-prediction block according to an embodiment of the present application. That is, Fig. 2 shows a corresponding decoder 20, i.e. an apparatus 20 configured to predictively decode a video 11' composed of a picture 12' in a picture block from a data stream 14, again by way of example using transform-based residual decoding, the apostrophe being used to indicate that the picture 12' and the video 11' reconstructed by the decoder 20 deviate from the picture 12 originally coded by the apparatus 10, respectively, in terms of coding loss introduced by quantization of the prediction residual signal. Figs. 1 and 2 use, by way of example, transform-based predictive residual coding, although the embodiment of the present application is not limited to this kind of predictive residual coding. This also applies to other details described with respect to Figs. 1 and 2, as outlined below.

[0046] The encoder 10 is configured to subject the prediction residual signal to a spatial-to-spectral transformation and to encode the prediction residual signal thus obtained into a data stream 14. Similarly, the decoder 20 is configured to decode the prediction residual signal from the data stream 14 and to subject the prediction residual signal thus obtained to a spectral-to-spatial transformation.

[0047] Internally, the encoder 10 may comprise a prediction residual signal former 22 which generates a prediction residual 24 so as to measure the deviation of a prediction signal 26 from an original signal, i.e. the video 11 or the current picture 12. The prediction residual signal former 22 may for example be a subtractor which subtracts the prediction signal from the original signal, i.e. the current picture 12. The encoder 10 then further comprises a transformer 28 which subjects the prediction residual signal 24 to a spatial-spectral transformation to obtain a spectral-domain prediction residual signal 24' which is then quantized by a quantizer 32 configured by the encoder 10. The prediction residual signal 24'' thus quantized is coded into the data stream 14. For this purpose, the encoder 10 optionally comprises an entropy coder 34 which entropy codes the prediction residual signal so as to be transformed and quantized into the data stream 14. The prediction residual 26 is generated by a prediction stage 36 of the encoder 10 based on the prediction residual signal 24'' decoded to and from the data stream 14. For this purpose, the prediction stage 36 may internally comprise an inverse quantizer 38 for inverse quantizing the prediction residual signal 24'' to obtain a spectral domain prediction residual signal 24''' corresponding to the signal 24' excluding the quantization losses, and then an inverse transformer 40 for subjecting the latter prediction residual signal 24'' to an inverse transformation, i.e. a spectral-spatial transformation, to obtain a prediction residual signal 24'''' corresponding to the original prediction residual signal 24 excluding the quantization losses. A combiner 42 of the prediction stage 36 then recombines, e.g. by adding, the prediction signal 26 and the prediction residual signal 24'''' to obtain a reconstructed signal 46a, i.e. a reconstruction (reconstructed version) of the original signal 12. The reconstructed signal 46a may correspond to the signal 12'.

[0048] An in-loop filter 90 filters the reconstructed signal 46a to obtain a version of a decoded picture, e.g., a decoded signal 46b of the currently decoded picture or a subsequent decoded picture, and inserts it into a decoded picture buffer DPB 92.

[0049] A prediction module 44 of the prediction stage 36 then generates a prediction signal 26 based on the signal 46b, for example by using spatial prediction, i.e. intra-prediction, and / or temporal prediction, i.e. inter-prediction, as described in more detail below.

[0050] The decoder 20 includes a decoding core 94 that includes an entropy decoder 50 , an inverse quantizer 52 , an inverse transformer 54 , a combiner 56 , a prediction module 58 , an in-loop filter 90 , and a DPB 94 .

[0051] Similarly, the decoder 20 may be internally configured from components corresponding to the prediction stage 36 and interconnected in a corresponding manner thereto. In particular, an entropy decoder 50 of the decoder 20 is able to entropy decode the quantized spectral domain prediction residual signal 24'' from the data stream, whereby the inverse quantizer 52, the inverse transformer 54, the combiner 56 and the prediction module 58 are interconnected in the manner described above with respect to the modules of the prediction stage 36 and cooperate to recover a reconstructed signal based on the prediction residual signal 24'', such that the output of the combiner 56 results in a reconstructed signal, i.e. the video 11' or the current picture 12' thereof, as shown in FIG.

[0052] Although not specifically mentioned above, it is readily apparent that the encoder 10 may set some coding parameters, including, for example, prediction mode, motion parameters, etc., according to some optimization scheme, such as, for example, optimizing some rate- and distortion-related criteria, i.e., encoding cost, and / or using some rate control. As will be explained in more detail below, the encoder 10 and the decoder 20 and the corresponding modules 44, 58 each support different prediction modes, such as intra- and inter-coding modes, which form a kind of set or pool of primitive prediction modes, in which predictions of picture blocks are configured in a manner that will be explained in more detail below. The granularity at which the encoder and the decoder switch between these prediction synthesis corresponds to a subdivision of the pictures 12 and 12' into blocks, respectively. It should be noted that some of these blocks may be blocks that are solely intra-coded, some blocks may be blocks that are solely inter-coded, and optionally further blocks may be obtained using both intra- and inter-coding, as will be explained in more detail below. According to the intra-coding mode, a prediction signal for a block is obtained based on the spatial, already coded / decoded neighborhood of the respective block. There may be several intra-coding sub-modes, among which certain intra-prediction parameters are represented: There may also be directional or angular intra-coding sub-modes, in which the prediction signal for each block is filled in by extrapolating neighboring sample values ​​to each block along a certain direction specified for each directional intra-coding sub-mode.The intra-coding sub-modes may also comprise one or more further sub-modes, such as, for example, a DC coding mode in which the prediction signal of the respective block assigns a DC value to all samples in the respective block, and / or a planar intra-coding mode in which the prediction signal of the respective block is approximated or determined to be a spatial distribution of sample values ​​described by a two-dimensional linear function over the sample positions of the respective block, and derives the slope and offset of the plane defined by the two-dimensional linear function based on neighboring samples. In comparison, according to the inter-prediction modes, the prediction signal for a block can be obtained, for example, by predicting the block interior temporally. For the parameterization of the inter-prediction modes, a motion vector may be signaled in the data stream, indicating the spatial displacement of the part of the previously coded picture of the video 11 from which the previously coded / decoded picture is sampled in order to obtain the prediction signal for the respective block. This means that in addition to the residual signal coding constituted by the data stream 14, such as the entropy coded transform coefficient levels representing the quantized spectral domain prediction residual signal 24'', the data stream 14 may also be coded into prediction related parameters for assigning to the block prediction modes, prediction parameters for the assigned prediction modes, such as motion parameters for inter prediction modes, and optionally further parameters that control the construction of the final prediction signal for the blocks using the assigned prediction modes and prediction parameters, as will be described in more detail below. Additionally, the data stream may contain parameters that control and signal the subdivision of the pictures 12 and 12', respectively, into blocks. The decoder 20 uses these parameters to subdivide the pictures in a similar way as the encoder did, to assign the same prediction modes and parameters to the blocks, and to make the same predictions to obtain the same prediction signals.

[0053] FIG. 3 shows a schematic diagram of an example of the relationship between the prediction residual signal, the prediction signal and the reconstructed signal, respectively showing the possibility of setting the subdivisions defining the prediction signal, the treatment of the prediction residual signal, etc. That is, FIG. 3 shows the relationship between the reconstructed signal, i.e. the reconstructed picture 12′, on the one hand, and the prediction residual signal 24″″ as signaled in the data stream, and on the other hand, the prediction signal 26. As already mentioned above, the combinations may be additive. The prediction signal 26 is, merely by way of example, a subdivision of the picture area into blocks 80 of various sizes. The subdivision may be any subdivision, such as a regular subdivision of the picture area into rows and columns of blocks, or a multi-tree subdivision, which subdivisions the picture 12 into leaf blocks of various sizes, such as a quad-tree subdivision, or a mixture thereof, in which the picture area is first subdivided into rows and columns of tree root blocks and then further subdivided according to a recursive multi-tree subdivision into blocks 80.

[0054] Each aspect of the present invention will now be described.

[0055] Suffix-APS According to one aspect of the present invention, an encoder allows an encoder to start transmitting a portion of a picture (e.g., a slice) before finishing the encoding process for the entire picture while still using the slice. This is achieved by allowing an Adaptation Parameter Set (APS) to be transmitted after the coded slices of a picture, which moves per Coding Tree Unit (CTU) ALF parameters behind the actual slice data.

[0056] A diagram of a state-of-the-art encoder is shown in Figure 4. First the whole picture is coded (intra prediction, motion estimation, residual coding, etc.) and then the ALF estimation process starts. The ALF filter coefficients are written to the APS and then slice data can be written including the ALF per CTU parameters (interspersed with other parameters). The picture can be transmitted only after the ALF coding is finished.

[0057] Figure 5 shows an example of a low-delay encoder as envisaged by the present invention. Slices can be sent before the picture coding process is finished. In particular, the APS carrying coefficients is moved after the slice data (VCL NAL unit).

[0058] In this process, the encoder can collect estimated ALF parameters (filter coefficients, filter control information) and then send out the coded slices of a picture first, collecting the APS containing the ALF parameters after the coded picture. The decoder can start parsing and decoding the slices of a picture as soon as they arrive. Because the ALF is one of the last decoding steps, the ALF parameters can arrive after the coded picture to be applied after the other decoding steps.

[0059] The present invention includes the following aspects. - An APS type indicating that the APS belongs to the previous picture. The APS type is coded in the syntax element, as follows: - New NAL unit types (e.g., suffix APS) encoded in the NAL unit header. * New APS types encoded in APS (e.g. suffix ALF APS). A flag indicating whether APS applies to the previous or subsequent picture. -Changes in the decoding process, which only assumes the start of a new access unit AU by the signaled prefix APS, and not by the suffix APS. Alternatively, the APS type (prefix or suffix) may be determined by its relative position in the bitstream with respect to the surrounding access unit delimiters (AUDs) and the coded slices of the picture. If the APS is located between the last VCL NAL unit of a picture and the AUD, it applies to the previous picture. If the APS is located between the AUD and the first VCL NAL unit of a picture, it applies to the next picture. In this case, the decoder only needs to determine the start of a new access unit by the position of the AUD. In one embodiment, the slice header indicates that a suffix APS is used instead of a prefix APS, so that the dependency is resolved at the end of the picture decoding process, for example by the following equation: o Signaling the APS identifier at a position within the slice header depending on its prefix or suffix characteristics. o Signal a flag indicating that the referenced APS follows slices coded in bitstream order.

[0060] Typically, not only is the derivation of the ALF parameters (filter coefficients) performed towards the end of the encoding process (based on the reconstructed sample values), but also further ALF control information (information about whether and how a coding tree unit CTU is filtered) is derived at this stage. The ALF control information is carried in several syntax elements per coding_tree_unit in the slice payload, interspersed with block partitioning (e.g. as shown in Figure 6b), transform coefficients, etc. For example, the following syntax elements may be present: alf_ctb_flag: Specifies whether to apply an adaptive loop filter to the coding tree block CTB. - alf_ctb_use_first_APS_flag: Specifies whether to use the filter information of the APS whose adaptive_parameter_set_id is equal to slice_alf_APS_id_luma[0]. alf_use_APS_flag: Specifies whether to apply the filter set from APS to the luma CTB. 〇Others.

[0061] All this ALF control information relies on the derivation of the ALF filter parameters towards the end of the picture encoding process.

[0062] In one embodiment, the ALF control information is signaled in a separate loop over the CTUs of the slice at the end of each slice payload so that the encoder can finalize the first part of the slice payload (transform coefficients, block structure, etc.) before the ALF is performed. This embodiment is shown in Figures 6a and 6b.

[0063] As shown in Figure 6a, a video coding unit (VCL NAL unit) 100 includes a slice header, slice data 108, and a portion (ALF per CUT APS) 106, with one or more parameter sets (ALF coefficients) 102 signaled separately, i.e., as a suffix APS (in non-VCL-NAL units). That is, each video coding unit 100 is arithmetically coded continuously across the data to the end of the portion, along the data stream order.

[0064] 6b shows that the slice data 108 is interspersed in the portion 106, i.e., the ALFs per CUT APS are interspersed in the block, and one or more parameter sets 102 are signaled separately as suffix APS.

[0065] In another embodiment, the slice header will indicate that the ALF control information is not indicated in syntax elements in the coded slice payload, i.e. in the CTU loop mentioned above, but is included in the suffix APS, i.e. in a separate loop over all CTUs within the respective suffix APS, with reference to an APS that is, for example, of suffix APS type.

[0066] In another embodiment, the slice header will indicate that the ALF control information is not indicated in the syntax elements in the coded slice payload, i.e., in the CTU loop described above, but is included in a new type of suffix APS that is different from the suffix APS that carries the ALF coefficients, i.e., in a separate loop over all CTUs in the respective reference APS, for example, with reference to an APS that is of suffix APS type. The data per CTU can be optionally CABAC coded. This embodiment is shown in Figure 7.

[0067] As shown in Fig. 7, the data units are signaled in data stream order: a video coding unit (VCL NAL unit) 100 including a slice header and slice data 108, a parameter set 104 (Suffix ALF CTU-data APS: non-VCL NAL unit), a further video coding unit 100, a further parameter set 104, and a parameter set (filter control information) 102 (Suffix ALF coefficient APS: non-VCL NAL unit). That is, it is the opposite of the data stream shown in Fig. 6a and 6b, and the filter coefficients do not need to be signaled following every video coding unit. In other words, the filter coefficients may be transmitted collectively for two or more video coding units 100 in bitstream order, or may be further used by a further video coding unit following the filter coefficients in bitstream order.

[0068] In another embodiment, slice headers that reference the suffix APS and all CTUs are inferred to have adaptive loop filters that are applied with default values ​​of the filter parameters and ALF control information signaled in the suffix APS.

[0069] Signaling a reference to a parameter set ID in AUD In the following, we will describe another aspect of the invention, namely a method for facilitating access to the list of all parameter sets referenced in a picture.

[0070] According to this aspect of the present invention, a decoder can easily determine whether all necessary parameter sets are available before starting decoding. -The list of all parameter sets used is contained in a high-level syntax structure. -The list consists of the following: ○ 1 VPS (video parameter set) 〇One DPS (Decoder Parameter Set) One or more SPS (Sequence Parameter Sets) One or more PPS (Picture Parameter Sets) One or more APS (Adaptation Parameter Sets), ordered by APS type Optionally, each list is preceded by one or more syntax elements indicating which parameter set types are lists (including the option to disable sending). - The syntax structures that hold the information are contained in Access Unit Delimiters (AUDs).

[0071] An example of the syntax is shown in Fig. 8, in which a given unit, i.e., AUD, includes multiple identifiers 200, such as a VPS identifier "aud_vps_id", a DPS identifier "aud_dps_id", an SPS identifier "aud_sps_id", and a PPS identifier "aud_pps_id".

[0072] Signaling APS ID in AUD only An APS is referenced by each slice of a picture. When combining bitstreams, it may be necessary to rewrite and / or combine different APSs.

[0073] To avoid rewriting the slice header, the APS ID is signaled in the access unit delimiter rather than in the slice header. Thus, in case of a change, there is no need to rewrite the slice header. Rewriting the access unit delimiter is a much easier operation.

[0074] An example of the syntax is shown in Figure 9.

[0075] In another embodiment, the APS ID is only transmitted in the AUD subject to another syntax element. If the syntax element indicates that the APS ID is not present in the AUD, the APS ID is present in the slice header. An example of the syntax is shown in Figure 10. That is, as shown in Figure 10, the AUD includes a flag 204, for example, the syntax "aps_ids_in_aud_enabled_flag".

[0076] 11a to 11c are schematic diagrams showing examples of relationships between predetermined encoding parameters and AUs according to the above-described embodiments shown in FIGS.

[0077] As shown in Fig. 11a, the multiple parameter sets 120 include one or more first predefined parameter sets 126 including, for example, APA and PPS, and one or more second predefined parameter sets 128 including, for example, SPS, DPS, and VPS. The second predefined parameter set 128 belongs to a higher hierarchical level than the first predefined parameter set 126. As shown in Fig. 11a, an AU includes multiple slice data, for example, VCL0 to VCLn, and the first and second predefined parameter sets are included in a predefined parameter set 122, for example, a parameter set for VCL0.

[0078] The multiple parameter sets 120 are stored in the AUD of the AU and signaled to the decoder.

[0079] As shown in Figure 11b, when flag 204 is included in an AUD, flag 204 indicates (205) whether a predefined identifier in identifier 200 that references a particular predefined parameter set 126b is present in a given unit 124 or whether predefined identifiers that reference a particular predefined parameter set 126b are present in one or more video coding units 100. That is, flag 204 indicates whether APS 126b is in the AUD or in the VLC (as indicated by the arrows in Figure 11b).

[0080] As shown in FIG. 11c, the first predefined parameter set 126 includes a third predefined parameter set 126a, e.g., PPS, that is referenced by an identifier in one or more video encoding units 100 (e.g., AU), and a fourth predefined parameter set 126b, e.g., APS, that is referenced by an identifier 200 (shown in FIGS. 8 and 9) that is present in a predefined unit 124 (e.g., AUD), but is not referenced by any of the identifiers in the one or more video encoding units 100 (AU) and is not referenced by any of the predefined parameter sets.

[0081] Signaling access unit characteristics to AUD Currently, the AUD indicates whether the following slice is of type I, B, or P. In most systems, this feature is not very useful since an I-picture does not necessarily mean that there is a random access point. Prioritization of AUs when they need to be dropped can usually be done in other ways, such as parsing their temporal ID, parsing whether they are discardable pictures (not referenced elsewhere), etc.

[0082] Instead of indicating picture types, one can indicate NAL unit types, as well as whether they are discardable pictures, etc. Furthermore, in the multi-layer case, it may become more difficult to describe the characteristics. The random access characteristics of a picture, specified by an overall NAL unit type (e.g., IDR, CRA, etc.) that is used for all VCL NAL units in an access unit instead of one specified in the NAL unit header. o Intra-layer pictures can be discarded in one layer but not collocated pictures in another layer. A picture within a layer is marked as no output (pic_output_flag) in one layer and is not a collocated picture in another layer.

[0083] Thus, in the embodiment shown in Figure 12a, the AUD indicates whether the information applies to a single layer or to all layers, i.e., the AUD flag refers to information about the AU characteristics, for example as shown below:

[0084] "layer_specific_aud_flag" 300: controls whether separate access units are defined in the video data stream for pictures associated with a given but different layer of the video data stream, or whether pictures associated with a given but different layer of the video data stream are coded in one of the access units; and / or nal_unit_type_present_flag 302: in case of a video coding type indication, indicates the video coding type of the video coding units in an access unit, which is assigned to the video coding units in an access unit, and the video coding units contained in an access unit are different from each other, i.e., indicates the NAL unit type by indicating the presence of a NAL unit type syntax element; and / or "discardable_flag" 304: indicates that the access unit is a picture that is not referenced by any other picture, and / or "pic_output_flag" 306: indicates a picture not to be output. In another embodiment, an AUD can indicate that the AUD is a subordinate AUD. This means the following: inherit parameters from the previous AUD of the subordinate layer, but add information specific to some layer, and / or *No new AU has started.

[0085] Figure 12b shows an indication in an AUD, i.e., the video coding type of a video coding unit is indicated by describing the random access characteristics of multiple pictures, i.e., the syntax "random_access_info_present_flag" indicates the random access characteristics of pictures, as shown by "all_pics_in_au_random_access_flag" in Figure 12b, which is specified by the overall NAL unit type (e.g., IDR, CRA, etc.) used for all VCL NAL units in the access unit, instead of being specified in the NAL unit header.

[0086] An example of syntax according to one embodiment of the present invention is shown in FIG.

[0087] In this example, the parameter set 308 indicates whether the implementation "layer_specific_aud_flag" indicates whether the information in the AUD applies to all layers, "dependent_aud_flag" indicates whether the AUD starts a new global access unit, or whether it is a "layer-access unit" only. In a dependent AUD, inheritance from the base layer AUD is indicated by "aud_inheritance_flag".

[0088] Although some aspects have been described in the context of an apparatus, it will be apparent that these aspects also represent a description of the corresponding method, in which a block or apparatus corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method step also represent a description of a corresponding block or item or feature of a corresponding apparatus. Some or all of the method steps may be performed by (or using) a hardware apparatus, such as, for example, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the most important method steps may be performed by such an apparatus.

[0089] The data stream of the present invention can be stored on a digital storage medium or can be transmitted over a transmission medium such as a wireless transmission medium or a wired transmission medium such as the Internet.

[0090] Depending on specific implementation requirements, the embodiments of the present application can be implemented in hardware or software. The implementation can be carried out using a digital storage medium, such as a floppy disk, DVD, Blu-ray, CD, ROM, PROM, EPROM, EEPROM, or flash memory, which stores electronically readable control signals that cooperate (or can cooperate) with a programmable computer system so that the respective method is executed. The digital storage medium may therefore be computer readable.

[0091] Some embodiments according to the invention comprise a data carrier having electronically readable control signals capable of cooperating with a programmable computer system to cause one of the methods described herein to be performed.

[0092] In general, embodiments of the present application can be implemented as a computer program product having program code operable to perform one of the methods when the computer program product is run on a computer. The program code may for example be stored on a machine readable carrier.

[0093] Other embodiments comprise the computer program for performing one of the methods described herein, stored on a machine readable carrier.

[0094] In other words, an embodiment of the inventive method is, therefore, a computer program having a program code for performing one of the methods described herein, when the computer program runs on a computer.

[0095] A further embodiment of the inventive method is therefore a data carrier (or digital storage medium, or computer readable medium) comprising recorded thereon a computer program for performing one of the methods described herein. The data carrier, digital storage medium, or recorded medium is typically tangible and / or non-transitory.

[0096] A further embodiment of the inventive method is therefore a data stream or a sequence of signals representing the computer program for performing one of the methods described herein, the data stream or the sequence of signals for example being adapted to be transferred via a data communication connection, for example via the Internet.

[0097] A further embodiment comprises a processing means, for example a computer, or a programmable logic device, configured to or adapted to perform one of the methods described herein.

[0098] A further embodiment comprises a computer having installed thereon the computer program for performing one of the methods described herein.

[0099] Further embodiments according to the invention comprise an apparatus or system configured to transfer (e.g. electronically or optically) a computer program for performing one of the methods described herein to a receiver. The receiver may for example be a computer, a mobile device, a memory device, etc. The apparatus or system may for example comprise a file server for transferring the computer program to the receiver.

[0100] In some embodiments, a programmable logic device (e.g., a field programmable gate array) may be used to perform some or all of the functions of the methods described herein. In some embodiments, a field programmable gate array may cooperate with a microprocessor to perform one of the methods described herein. In general, the methods are preferably performed by any hardware apparatus.

[0101] The apparatus described herein may be implemented using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer.

[0102] The apparatus described herein, or any components of the apparatus described herein, may be implemented at least in part in hardware and / or software.

Claims

1. a decoding core (94) configured to reconstruct a decoded picture from one or more video coding units (100) in an access unit AU of a video data stream to obtain a reconstructed version (46a) of the decoded picture, said decoding core (94) being configured to start reconstructing the decoded picture before receiving all the video coding units in the access unit AU; an in-loop filter (90) configured to filter the reconstructed version (46a) of the decoded picture to obtain a filtered version (46b) of the decoded picture; A parameterizer, comprising: reading in-loop filter control information for parameterizing the in-loop filter from one or more parameter sets (102, 104) located in the access unit AU of the decoded picture following the one or more video coding units (100) in data stream order; and parameterizing the in-loop filter (90) to filter the reconstructed version (46a) of the decoded picture in a manner responsive to the in-loop filter control information; a parameterizer configured to parameterize the in-loop filter by A video decoder comprising:

2. 2. The video decoder of claim 1, wherein the one or more video encoding units (100) include a header indicating that the one or more parameter sets (102, 104) follow the one or more video encoding units (100).

3. 3. The video decoder of claim 1, wherein the in-loop filter control information comprises one or more filter coefficients for parameterizing the in-loop filter in terms of a transfer function.

4. 4. A video decoder according to claim 1, wherein the in-loop filter control information comprises spatially selective in-loop filter control information for spatially varying filtering of the reconstructed version of the decoded picture by the in-loop filter.

5. 5. The video decoder of claim 1, wherein the parameterizer is configured to read in-loop filter control information from a portion (106) of the one or more video coding units (100) that follows data (108) contained in the one or more video coding units (100) in a data stream order.

6. 6. The video decoder of claim 5, wherein each video coding unit (100) arithmetically codes sequentially across the data in data stream order until the end of the portion (106).

7. 7. The video decoder of claim 1, wherein a predetermined parameter set (102) of the one or more parameter sets follows all of the one or more video coding units (100) in data stream order and comprises one or more filter coefficients for parameterizing the in-loop filter in terms of a transfer function.

8. 8. The video decoder of claim 1, wherein the one or more parameter sets include, for each of the one or more video encoding units (100), a further predetermined parameter set (104) following the respective video encoding unit (100) in data stream order and including spatially selective in-loop filter control information for spatially varying filtering of a reconstructed version of the decoded picture by the in-loop filter within a portion of a picture encoded in the respective video encoding unit (100).

9. 8. The video decoder of claim 1, wherein each of the one or more video encoding units (100) includes a filter information section (106) following the data section (108) of the respective video encoding unit (100) in data stream order, the filter information section including spatially selective in-loop filter control information for spatially varying filtering of the reconstructed version of the decoded picture by the in-loop filter within a portion of a picture in which block-based prediction parameter data and prediction residual data are encoded in the data section of the respective video encoding unit (100).

10. 10. The video decoder of claim 1, wherein the parameterizer is configured to place the one or more parameter sets (102, 104) for the decoded picture within the access unit AU at a position following the one or more video encoding units (100) along the data stream order in the case of a predetermined indication in the video data stream to assume a first state, and at a different position within the access unit AU preceding all of the one or more video encoding units (100) in the case of the predetermined indication in the video data stream to assume a second state.

11. 6. The video decoder of claim 5, wherein the portions (106) of the one or more video encoding units (100) are in a position along data stream order following data (108) constructed by the one or more video encoding units (100) in the case of a given indication in the video data stream to assume a first state, and in a different position within the one or more video encoding units among which the data is interspersed in the case of a given indication in the video data stream to assume a second state.

12. A video decoder according to claim 10 or 11, configured to read the predetermined indication from the one or more video encoding units (100).

13. 13. A video decoder according to claim 10, wherein the predetermined indication indicates the one or more parameter sets with one or more identifiers when the first state is assumed, and indicates one or more different in-loop filter control information parameter sets when the second state is assumed.

14. 14. A video decoder according to claim 10, configured to respond to the predetermined instructions on a per access unit basis so as to perform different arrangements for different access units of the video data stream if the predetermined instructions are different for different access units.

15. 15. The video decoder of claim 1, wherein the parameterizer is configured to reconstruct the decoded picture using the in-loop filter control information contained in a previously signaled access unit AU.

16. When detecting a boundary of an access unit AU, the video decoder interpreting a video coding unit conveying said in-loop filter control information in the form of one or more parameter sets (102, 104) as not starting an access unit AU; 16. The video decoder of claim 1, configured to interpret a video coding unit conveying in-loop filter control information not in the form of one or more parameter sets (102, 104) as starting an access unit.

17. reconstructing a decoded picture from one or more video coding units (100) in an access unit AU of a video data stream to obtain a reconstructed version of a decoded picture, the reconstruction starting before receiving all video coding units in the access unit AU; filtering the reconstructed version of the decoded picture with an in-loop filter to obtain a filtered version of the decoded picture; and parameterizing the in-loop filter; Parameterizing the in-loop filter comprises: reading in-loop filter control information for parameterizing the in-loop filter from one or more parameter sets (102, 104) located in the access unit AU of the decoded picture following the one or more video coding units (100) in data stream order; filtering the reconstructed version of the decoded picture in a manner responsive to the in-loop filter control information.

18. 20. The method of claim 17, wherein the one or more video encoding units (100) include a header indicating that the one or more parameter sets (102, 104) follow the one or more video encoding units (100).

19. encoding one or more video coding units (100) within an access unit AU of a video data stream and starting to transmit the video coding units before encoding all the video coding units within the access unit AU; and A video encoder configured to encode in-loop filter control information to parameterize an in-loop filter in one or more parameter sets (102, 104) in the access unit AU that follows the one or more video encoding units (100) along a data stream order.

20. 20. The video encoder of claim 19, wherein the one or more video encoding units (100) include a header indicating that the one or more parameter sets (102, 104) follow the one or more video encoding units (100).

21. encoding one or more video coding units (100) within an access unit AU of a video data stream and starting to transmit the video coding units before encoding all the video coding units within the access unit AU; and encoding in-loop filter control information to parameterize an in-loop filter in one or more parameter sets (102, 104) in the access unit AU that follows the one or more video coding units (100) along a data stream order.

22. 22. The method of claim 21 , wherein the one or more video encoding units (100) include a header indicating that the one or more parameter sets (102, 104) follow the one or more video encoding units (100).

23. 23. A computer readable medium having stored thereon a computer program for carrying out the method of any one of claims 17, 18, 21 or 22.

Images