Processing mono signals in 3D audio decoders delivering binaural content

Abstract

To provide a solution that allows delivery while optimizing a bandwidth required by a codec.SOLUTION: A method for processing a monophonic signal in a 3D audio decoder includes a step of executing binauralization processing on decoded signals intended to be delivered spatially by a headset. In the method, upon detection (E200), in a data stream representative of the monophonic signal, of an indication of non-binauralization processing, the indication being associated with processing of spatial position information, the decoded monophonic signal is directed (O-E200) to a stereophonic processing engine, which takes into account the position information to construct (E220) two processed channels, the two channels being directly processed via a direct mixing step (E230) that sums the two channels with a binauralized signal output from the binauralization processing, in order to be delivered (E240) via the headset. A decoder device that implements the processing method is also provided.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to the processing of audio signals in 3D audio decoding systems, such as codecs that meet the MPEG-H3D audio standard, and more particularly to the processing of mono signals intended for processing by a headset that also receives a binaural audio signal. [Background technology]

[0002] The term binaural refers to the processing of audio signals by an audio headset or a pair of earphones, but with spatialization effects. Binaural processing of audio signals, hereafter called binauralization or binauralization processing, uses HRTF (Head Related Transfer Function) filters in the frequency domain, or HRIR, BRIR (Head-Related Impulse Response, Binaural Room Impulse Response) filters in the time domain to reproduce the acoustic transfer function between the sound source and the listener's ears. These filters serve to simulate the auditory location cues that allow the listener to localize the sound source as if he were in a real listening situation.

[0003] The signal for the right ear is obtained by filtering the mono signal with a right ear transfer function (HRTF) and the signal for the left ear is obtained by filtering the same mono signal with a left ear transfer function. In NGA (Next Generation Audio) codecs such as MPEG-H3D audio described in (Non-Patent Document 1) or also in AC4 described in (Non-Patent Document 2), the signal received by the decoder is first decoded and then subjected to a binauralization process as described above before processing by the audio headset. One of the concerns here is that the audio processed by the audio headset is spatialized, i.e. in the case of using binaural signals.

[0004] The above mentioned codecs therefore form the basis not only of the possibility of processing binaural signals heard through a headset with several virtual loudspeakers, but also of the possibility of processing spatialized sound with several real loudspeakers.

[0005] In certain cases, binaural processing is associated with tracking the listener's head (head tracking), which is also called dynamic processing as opposed to static processing. This type of processing allows the listener's head movements to be taken into account in order to modify the sound processed for each ear in order to keep the processing of the sound scene stable. In other words, the listener will perceive the sound source as being located at the same place in physical space, regardless of whether he moves his head or not.

[0006] This can be important when watching 360° video content.

[0007] However, it is not desirable to process certain content with this type of processing. In particular, in certain cases, if the content is specifically created for binaural processing, for example if the signals were recorded directly with an artificial head or have already been processed with a binauralization process, they need to be processed directly with the earphones of the headset. These signals do not require additional binauralization processing.

[0008] Similarly, content creators may want to process the audio signal in such a way that it is perceived as independent of the audio scene, i.e. as a separate sound from the audio scene, for example in the case of a voice-off.

[0009] This kind of processing can, for example, provide explanations for the audio scene that is being further processed. For example, a content creator may want to process audio for one ear to intentionally create an "earbuds" effect, i.e., the audio is heard in only one ear. It may be desired that the audio is never heard in the other ear, even if the listener moves their head as in the previous example. A content creator may also want the audio to be processed at a precise location in the audio space with respect to the listener's ears (not just inside one ear), even if the listener moves their head.

[0010] When such a mono signal is decoded and input to a processing system such as the MPEG-H3D Audio or AC4 codec, it will be binauralized. The sound is then distributed between both ears (even if the other ear is quiet) and even if the listener moves his / her head, his / her ears will not perceive the sound in the same way, if head tracking processing is used, since the position of the sound source remains in the same position as in the original sound scene. The volume at each of the two ears will therefore be perceived as varying depending on the head position.

[0011] In one proposed amendment to the MPEG-H3D audio standard, (Non-Patent Document 3) it is proposed to identify content that should not be altered by binauralization.

[0012] Thus, the "dichotic" identification is associated with content that should not be binauralized.

[0013] Thus, all sound elements are binauralized except for what is called "dichotic," meaning that a different signal is sent to each ear.

[0014] Similarly, in the AC4 standard, a data bit indicates that the signal has already been virtualized. This bit allows post-processing to be disabled. Content thus identified is content already formatted for audio headsets, i.e. binaural content. They contain two channels.

[0015] These methods do not address the case of mono signals where the producer of the audio scene does not want to binauralize.

[0016] This prevents the mono signal from being processed independently of the sound scene at a precise location relative to the listener's ear in what is called "earphone" mode. One way to achieve the desired processing for one ear using conventional two-channel techniques is to generate two-channel content consisting of a signal in one channel and silence in the other, or indeed to generate stereo content taking into account the desired spatial location and to recognize this content as already spatialized before transmission.

[0017] However, this type of processing is complicated by the need to generate the above-mentioned stereo content, and requires additional bandwidth for the transmission of this stereo content. [Prior art documents] [Non-patent literature]

[0018] [Non-Patent Document 1] ISO / IEC23008-3 “High efficiency coding and media delivery in heterogenous environments-Part 3:3D audio”(25 / 07 / 2014) [Non-Patent Document 2] ETSI TS 103 190 “Digital Audio Compression Standard”(April,2014) [Non-Patent Document 3] ISO / IEC JTC1 / SC29 / WG11 MPEG2015 / M37265(October 2015) Summary of the Invention [Problem to be solved by the invention]

[0019] There is therefore a need to provide a solution that allows the delivery of a signal that is processed at a precise location relative to one ear of an audio headset wearer, independent of the audio scene processed by the same headset, while optimizing the bandwidth required for the codec used.

[0020] The present invention aims to improve this situation. [Means for solving the problem]

[0021] For this purpose, a method for processing an audio mono signal in a 3D audio decoder is proposed, which comprises a step of performing a binauralization process on a decoded signal intended for spatial processing by an audio headset, in which, upon detection in a data stream representing the mono signal of an indication of a non-binauralization process associated with processing of spatial position information, the decoded mono signal is directed to a stereo processor which takes into account the position information and constructs two processing channels, the two channels being processed in a direct mixing step which sums the two channels with the binaural signal resulting from the binauralization process, intended for processing by an audio headset.

[0022] Thus, by specifying that mono content should be processed at a precise spatial location relative to one of the listener's ears and not undergo binauralization processing, the processed signal can be made to have an "earphone" effect, i.e., to be heard by the listener at a defined location within the listener's head relative to one ear, just like a stereo signal, even if the listener's head moves.

[0023] Specifically, stereo signals are characterized by the fact that each sound source is present in each of the two (left and right) output channels with a volume difference (or ILD for short, Interaural Level Difference) and sometimes a time difference (or ITD for short, Interaural Time Difference) between the channels. When stereo signals are listened to with a headset, the sound sources are perceived at a location inside the listener's head, located between the left and right ear, depending on the ILD and / or ITD. Binaural signals differ from stereo signals in that filters are applied to the sound sources that replicate the acoustic path from the sound sources to the listener's ears. When binaural signals are listened to with a headset, the sound sources are perceived at a location located on a sphere outside the head, depending on the filters used.

[0024] Stereo and binaural signals are similar in that they contain two channels (left and right) and differ in the content of these two channels.

[0025] The processed mono (short for mono) signal is then overlaid with other processed signals to form a 3D sound scene.

[0026] The bandwidth required to present this type of content is optimized since it is sufficient to simply code an indication of the position within the audio scene in addition to the non-binauralization instruction to inform the decoder what processing to perform, as opposed to methods that require a stereo signal taking into account this spatial position to be coded, transmitted and then decoded.

[0027] The various specific embodiments described below may be added independently or in combination with each other to the steps of the processing method described above.

[0028] In one particular embodiment, the processed spatial position information is binary data representing a single channel of a processed audio headset.

[0029] The above information requires only one coding bit, further limiting the required bandwidth.

[0030] In this embodiment, only the processed channels corresponding to the channels indicated by the binary data are summed with the corresponding channels of the binaural signal in the direct mixing step, and the values ​​of the other processed channels are null.

[0031] Summing performed in this manner is simple to implement and achieves the desired "earphone" effect of superimposing a mono signal onto the processed audio scene.

[0032] In one particular embodiment, the mono signal is a channel-type signal that is directed to a stereo processor along with processing spatial position information.

[0033] Therefore, the mono signal does not undergo a step in which a binauralization process is performed, and is not processed like a channel-based signal as it is conventionally processed in prior art methods, but is processed by a stereo processor that is different from the existing processors used for channel-based signals, which replicate the mono signal in two channels but applies coefficients to the two channels that depend on the processed spatial position information.

[0034] The above-mentioned stereo processor may further be incorporated into a channel processor so that processing differs depending on the detection applied to the signal input to the processor, or may be incorporated into a direct mixing module which sums the channels generated by the stereo processor with the binaural signal generated by a module performing binaural processing.

[0035] In one embodiment associated with the above mentioned channel-type signals, the processed spatial location information is ILD data relating to the interaural level difference, or more generally information regarding the level ratio between the left and right channels.

[0036] In another embodiment, the mono signal is an object-type signal associated with a set of processing parameters including de-binauralization instructions and processing position information, and the signal is directed toward a stereo processor with the processing spatial position information.

[0037] In the alternative embodiment described above, the processing space position information is, for example, data relating to azimuth angles.

[0038] The above information allows the processing location relative to the ears of the wearer of the audio headset to be identified so that the audio is processed to be superimposed on the audio scene.

[0039] The mono signal is therefore not subjected to a step in which a binauralisation process is performed and is not processed like an object type signal, which is conventionally processed with prior art methods. This signal is processed by a stereo processor that is different from the existing processors used for object type signals. The non-binauralisation processing instructions and processing position information are included in the processing parameters (metadata) associated with the object type signal. This processor may further be integrated into the object processor or into a direct mix module that sums the channels generated by this stereo processor with the binaural signal generated by the module performing the binauralisation process.

[0040] The invention also relates to a device for processing a mono audio signal, comprising a module for performing a binauralization process on a decoded signal intended for spatial processing by an audio headset, said device comprising: a detection module capable of detecting, in a data stream representative of a mono signal, indications of a de-binauralization process associated with processed spatial position information; a transfer module capable of directing the decoded mono signal to a stereo processor if the detection by the detection module is successful; - a stereo processor capable of constructing two processing channels taking into account position information; a direct mixing module capable of directly processing the two processing channels by summing them with a binaural signal generated by a module performing binaural processing, for processing by an audio headset.

[0041] This device has the same advantages as the above-mentioned method which it implements.

[0042] In one particular embodiment, the stereo processor is integrated directly into the mix module.

[0043] Thus, the processing channels are built only in the direct mix module, and then only the position information is sent to the direct mix module together with the mono signal, which may be of channel or object type.

[0044] In one embodiment, the mono signal is a channel type signal and the stereo processor is integrated into a channel processor which further constructs processing channels for the multi-channel signal.

[0045] In another embodiment, the mono signal is an object type signal and the stereo processor is integrated into the object processor which further constructs a processing channel for the mono signal associated with a set of processing parameters.

[0046] The invention also relates to an audio decoder including a processing device as described above, and to a computer program comprising code instructions for carrying out the steps of the processing method described above when executed by a processor.

[0047] Finally, the invention relates to a processor-readable storage medium, optionally removable and which may or may not be integrated into the processing device, storing a computer program comprising instructions for carrying out the above-mentioned processing method.

[0048] Other characteristics and advantages of the invention will become apparent from a study of the following description, given solely as a non-limiting example, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0049] [Figure 1] 1 shows an MPEG-H3D audio decoder as found in the prior art; [Diagram 2] 3 illustrates steps of a processing method according to one embodiment of the present invention. [Diagram 3] 1 shows a decoder including a processing device according to a first embodiment of the invention; [Figure 4]4 shows a decoder including a processing device according to a second embodiment of the invention; [Diagram 5] 2 illustrates a hardware representation of a processing device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0050] Figure 1 shows diagrammatically a decoder standardised by the MPEG-H3D audio standard as specified in the above mentioned document. Block 101 is a core decoding module which decodes both the multi-channel audio signal of type "channel" (Ch.) and the mono audio signal of type "object" (Obj.) associated with the (metadata) spatialisation parameters (Obj.MeDa.) and the audio signal in the HOA (short for Higher Order Ambisonic) audio format.

[0051] The channel type signals are decoded and processed by a channel processor 102 (also called a "format converter" in the MPEG-H3D audio standard) to make the channel signals compatible with the audio processing system. The channel processor is aware of the characteristics of the processing system and therefore delivers one signal per processing channel (Rdr.Ch) for feeding real or virtual speakers (which are then binauralized for processing by a headset).

[0052] The above mentioned processing channels are blended by a blending module 110 with other processing channels generated by the object and HOA processors 103, 105 described below.

[0053] An object type signal (Obj.) is a mono signal associated with metadata such as spatialization parameters (azimuth, elevation), priority parameters or audio volume parameters that allow the mono signal to be placed in a spatialized audio scene. This object signal and the associated parameters are decoded by a decoding module 101 and processed by an object processor 103 that recognizes the characteristics of the processing system and adapts these mono signals to these characteristics. The various processed channels (Rdr.Obj.) thus generated are mixed by a mixing module 110 with the channels and other processed channels generated by the HOA processor.

[0054] Similarly, the HOA (short for Higher Order Ambisonic) signal is decoded and the decoded Ambisonic components are input to an HOA processor 105 to adapt these components to an audio processing system.

[0055] The processing channel (Rdr.HOA) generated by the HOA processor mentioned above is mixed at 110 with the processing channels generated by the other processors 102 , 103 .

[0056] The signal output from the mixing module 110 may be processed by real speakers HP arranged in the processing room. In this case, the signal output from the mixing module may be directly supplied to these real speakers, with one channel corresponding to one speaker.

[0057] The signals output from the mixing module are processed by an audio headset CA and then these signals are processed by a module 120 that performs binauralization processing, for example using the binauralization techniques described in the cited documents for the MPEG-H3D audio standard.

[0058] Thus, all signals intended for processing by an audio headset are processed by a module 120 which performs the binauralization process.

[0059] FIG. 2 illustrates steps of a processing method according to one embodiment of the present invention.

[0060] The method concerns the processing of a mono signal in a 3D audio decoder. Step E200 detects whether the data stream (SMo) representing the mono signal (e.g. the bitstream input to the audio decoder) contains a non-binauralization instruction associated with processed spatial position information. If not (N in step E200), the signal needs to be binauralized. This is done by performing a binauralization process in step E210 before being processed in E240 by a processed audio headset. This binaural signal may be mixed with another stereo signal generated in step E220 below.

[0061] If the data stream representing the mono signal contains both a non-binaural indication (Di.) and spatial position information (Pos.) (Y in step E200), the decoded mono signal is directed to a stereo processor for processing in step E220.

[0062] The non-binauralization instruction mentioned above may for example be a "binaural" identifier given to the mono signal, as in the prior art, or another identifier understood as an instruction not to process the signal by binauralization processing. The processing spatial location information may for example be an indication of the level difference between the left and right channels, such as an azimuth angle indicating the processing location of the sound with respect to the left or right ear, or ILD information allowing the energy of the mono signal to be distributed between the left and right channels, or an instruction to use a single processing channel corresponding to the right or left ear. In the latter case, this information is binary information requiring only a very narrow bandwidth (one data bit).

[0063] In step E220, two processing channels for the two earphones of the audio headset are constructed, taking into account the position information. The two processing channels thus constructed are directly processed by a direct mixing step E230 which sums these two stereo channels with the two binaural signal channels resulting from the binauralization process E210.

[0064] Each of the stereo processed channels is then summed with the corresponding binaural signal.

[0065] Following the direct mixing step described above, the two processed channels produced in the mixing step E230 are processed by an audio headset CA at E240.

[0066] In embodiments where the processing spatial location information is binary data representing a single channel of the processing audio headset, this means that the mono signal needs to be processed in only one earphone of this headset. The two processing channels established by the stereo processor in step E220 therefore consist of one channel containing the mono signal, the other being null and therefore possibly non-existent.

[0067] Thus, in the direct mixing step E230, a single channel is summed with the corresponding channel of the binaural signal, the other channels being null, thus simplifying this mixing step.

[0068] Thus, a listener wearing an audio headset hears, on the one hand, a spatialized audio scene generated from the binaural signals (in the case of dynamic processing, the physical layout of the audio scene heard by the listener does not change even if the listener moves his or her head), and, on the other hand, an audio sound independently superimposed on the audio scene, located within the head, between one ear and the centre of the head, i.e. this audio sound is heard at the same position in relation to one ear even if the listener moves his or her head.

[0069] This sound is therefore perceived as being superimposed on other binaurally generated sounds in the sound scene and serves, for example, as a voice-off in this sound scene.

[0070] Thus an "earphone" effect is achieved.

[0071] Figure 3 shows a first embodiment of a decoder including a processing device implementing the processing method described with reference to figure 2. In this exemplary embodiment, the mono signal processed by the implemented processing is a channel type signal (Ch.).

[0072] Object type signals (Obj.) and HOA type signals (HOA) are processed by respective blocks 303, 304 and 305 similar to blocks 103, 104 and 105 described with reference to Figure 1. Similarly, mixing block 310 performs mixing as described with reference to block 110 of Figure 1.

[0073] Block 330 receives channel-based signals and processes mono signals that contain non-binauralization instructions (Di.) associated with processed position spatial information (Pos.) differently than other signals that do not contain this information, in particular multi-channel signals, which are processed in block 302 in a similar manner to block 102 described with reference to FIG.

[0074] For mono signals that include a non-binauralization instruction associated with processed spatial position information, block 330 acts as a router or switch and directs the decoded mono signal (Mo.) to a stereo processor 331. The stereo processor further receives spatial position information (Pos.) from the decoding module, which allows it to construct two processed channels (2Vo.) corresponding to the left and right channels of the processed audio headset, so that these channels can be processed by the audio headset CA.

[0075] In one exemplary embodiment, the processed spatial position information is information about the binaural level difference between the left and right channels, which allows the determination of the coefficients that need to be applied to each processed channel to achieve this processed spatial position.

[0076] These coefficients may be defined as in the document MPEG-2 AAC: ISO / IEC 13818-4:2004 / DCOR2, section 7.2 AAC describing intensity stereo.

[0077] Prior to processing by the audio headset, the processing channels described above are added to the channels of the binaural signal generated by a binauralization module 320 which performs the binauralization process similar to block 120 of FIG.

[0078] The above-mentioned steps of combining channels are performed by the direct mixing module 340, which combines the left channel generated by the stereo processor 331 with the left channel of the binaural signal generated by the binaural processing module 320 and combines the right channel generated by the stereo processor 331 with the right channel of the binaural signal resulting from the binaural processing module 320, prior to processing by the headset CA.

[0079] Therefore, the mono signal does not pass through the binaural processing module 320 but is sent directly to the stereo processor 331 before being mixed directly with the binaural signal.

[0080] The above mentioned signals are therefore also not subjected to head tracking processing: the processed sound is therefore at the processing position relative to one of the listener's ears and remains in this position even if the listener moves his / her head.

[0081] In this embodiment, the stereo processor 331 may be integrated into the channel processor 302, which, upon receiving the processing spatial position information (Pos.), performs both the adaptation of the conventional channel-type signal as described above with reference to Fig. 1 and the construction of the two processing channels of the processor 331. Thus, only the two processing channels are directly transferred to the mixing module 340 before processing by the audio headset CA.

[0082] In a variant embodiment, the stereo processor 331 is integrated into the direct mixing module 340. In this case, the routing module 330 directs the decoded mono signal (where the non-binauralization instruction and the processed spatial position information have been detected) to the direct mixing module 340. Furthermore, the decoded processed spatial position information (Pos.) is also sent to the direct mixing module 340. This direct mixing module thus includes a stereo processor and therefore performs the construction of two processed channels taking into account the processed spatial position information and the mixing of these two processed channels with the processed channel of the binaural signal generated by the binauralization processing module 320.

[0083] Figure 4 shows a second embodiment of a decoder including a processing device implementing the processing method described with reference to figure 2. In this exemplary embodiment, the mono signal processed with the implemented processing is an object type signal (Obj.).

[0084] The channel type signal (Ch.) and the HOA type signal (HOA) are processed by respective blocks 402, 405 in the same manner as for blocks 102, 105 described with reference to Figure 1. Similarly, the mixing block 410 performs mixing as described with reference to block 110 of Figure 1.

[0085] Block 430 receives an object-type signal (Obj.) and processes a mono signal in which non-binauralization instructions (Di.) associated with processed position space information (Pos.) are detected in a different manner than another mono signal in which such information is not detected.

[0086] For mono signals in which this information is not detected, the signal is processed by block 403 similar to block 103 described with reference to FIG. 1, using parameters decoded by block 404 which decodes the metadata similar to block 104 of FIG. 1.

[0087] In the case of an object-type mono signal in which a non-binauralization instruction associated with the processed spatial position information has been detected, block 430 functions as a router or switch to direct the decoded mono signal (Mo.) to a stereo processor 431.

[0088] The non-binauralization instruction (Di.) and the processed spatial position information (Pos.) are decoded by a block 404 for decoding metadata or parameters associated with object type signals. The non-binauralization instruction (Di.) is sent to a routing block 430 and the processed spatial position information is sent to a stereo processor 431.

[0089] The above-mentioned stereo processor receiving spatial position information (Pos.) in this way can construct two processing channels corresponding to the left and right channels of the processed audio headset, and process these channels through the audio headset CA.

[0090] In one exemplary embodiment, the processing spatial position information is azimuth information that determines the angle between the desired processing position and the center of the listener's head.

[0091] With this information it is possible to determine the coefficients that need to be applied to each processing channel to achieve this processing spatial position.

[0092] The gain coefficients for the left and right channels can be calculated in the manner described in the article "Virtual Sound Source Positioning Using Vector Base Amplitude Panning" by Ville Pulkki in J. Audio Eng. Soc., Vol. 45, No. 6, June, 1997.

[0093] For example, the gain factor of a stereo processor is given by: g1=(cosO.sinH+sinO.cosH) / (2.cosH.sinH) g2=(cosO.sinH-sinO.cosH) / (2.cosH.sinH) Here, g1 and g2 correspond to the coefficients of the left and right channel signals, O is the angle between the forward direction and the object (called the azimuth angle), and H is the angle between the forward direction and the position of the virtual speaker (corresponding to the half angle between the speakers), which is set to, for example, 45°.

[0094] Prior to processing by the audio headset, these processing channels are added to the channels of the binaural signal generated by a binauralization module 420 which performs the binauralization process similar to block 120 of FIG.

[0095] The above-mentioned steps of combining channels are performed by a direct mixing module 440 which combines the left channel generated by the stereo processor 431 with the left channel of the binaural signal generated by the binaural processing module 420 and combines the right channel generated by the stereo processor 431 with the right channel of the binaural signal resulting from the binaural processing module 420, prior to processing by the headset CA.

[0096] Therefore, the mono signal does not pass through the binaural processing module 420 but is sent directly to the stereo processor 431 before being directly mixed with the binaural signal.

[0097] The above mentioned signals are therefore also not subjected to head tracking processing: the processed sound is therefore at the processing position relative to one of the listener's ears and remains in this position even if the listener moves his / her head.

[0098] In this embodiment, the stereo processor 431 may be integrated into the object processor 403, which then performs both the conventional adaptation of the object type signal as described with reference to Fig. 1 and the construction of the two processing channels of the processor 431 as described above, when it receives the processing spatial position information (Pos.) from the parameter decoding module 404. Then only the two processing channels (2Vo.) are forwarded to the direct mixing module 440 before processing by the audio headset CA.

[0099] In a variant embodiment, the stereo processor 431 is integrated in the direct mixing module 440. In this case, the routing module 430 directs the decoded mono signal (Mo.) (for which the non-binauralization instruction and the processed spatial position information have been detected) to the direct mixing module 440. Furthermore, the decoded processed spatial position information (Pos.) is also sent by the parameter decoding module 404 to the direct mixing module 440. This direct mixing module thus includes a stereo processor, and therefore performs the construction of two processed channels taking into account the processed spatial position information, and the mixing of these two processed channels with the processed channel of the binaural signal generated by the binauralization processing module 420.

[0100] FIG. 5 now shows an example of a hardware embodiment of a processing device capable of implementing the processing method according to the present invention.

[0101] The device DIS comprises a storage space 530, for example a memory MEM, and a processing unit 520 comprising a processor PROC controlled by a computer program Pg stored in the memory 530 and for executing the processing method according to the invention.

[0102] The computer program Pg comprises code instructions for carrying out the steps of the processing method according to the invention, which instructions are executed by the processor PROC and in particular perform the step, upon detection, in a data stream representing a mono signal, of an indication of a non-binauralisation processing associated with processed spatial position information, of directing the decoded mono signal to a stereo processor which takes into account the position information and constructs two processed channels which are directly processed by a direct mixing step which sums these two channels with the binaural signal resulting from the binauralisation processing for the purpose of processing by an audio headset.

[0103] Typically, the description of FIG. 2 applies to the algorithmic steps of such a computer program.

[0104] Upon initialization, the code instructions of the program Pg are loaded, for example, into a RAM (not shown) before being executed by the processor PROC of the processing unit 520. The program instructions may be stored in a storage medium such as a flash memory, a hard disk or any other non-transitory storage medium.

[0105] The device DIS comprises a receiving module 510 capable of receiving in particular a data stream SMo representative of a mono signal. The device DIS comprises a detection module 540 capable of detecting in this data stream indications of a non-binauralization process associated with processed spatial position information. The device DIS comprises a module 550 for directing, in case of successful detection by the detection module 540, the decoded mono signal to a stereo processor 560 capable of constructing two processing channels taking into account the position information.

[0106] The device DIS also includes a direct mixing module 570 capable of directly processing the two processed channels by summing them with the two channels of the binaural signal generated by the binauralization processing module, the processed channels thus obtained being transmitted via the output module 560 to the audio headset CA for processing.

[0107] The embodiments of these various modules are as described with reference to FIGS.

[0108] The term module may correspond to a software element or a hardware element or a combination of hardware and software elements, where a software element may correspond to one or more computer programs or subroutines or more generally any element of a program capable of implementing a function or set of functions as described for the module in question, and similarly a hardware element may correspond to any element of a hardware assembly (integrated circuit, chip card, memory card, etc.) capable of implementing a function or set of functions of the module in question.

[0109] The devices may be integrated into audio decoders such as those shown in figures 3 and 4 and may be integrated into multimedia devices such as set-top boxes or audio or video content readers, they may also be integrated into communication devices such as mobile phones or communication gateways. [Explanation of symbols]

[0110] 101 Decryption Module 102 Channel processing machine 103 Object Processing Machine 105 Processing equipment 110 Mixed Module 120 Modules 302 Channel processing machine 310 Mixed Block 320 Binaural Processing Module 331 Stereo Processing Machine 340 Direct Mixing Module 403 Object Processing Machine 404 Decode Metadata Block 410 Mixed Block 420 Binaural Processing Module 430 Routing Module 431 Stereo Processing Machine 440 Direct Mixing Module 510 Receiver Module 520 Processing Unit 530 Memory 540 Detection Module 550 Guidance Module 560 Stereo Processing Machine 570 Direct Mixing Module

Claims

1. 1. A method for processing an audio mono signal in a 3D audio decoder, comprising the step of performing a binauralization process on a decoded signal intended for spatial processing by an audio headset, the method comprising: Upon detecting in the data stream representative of the audio mono signal an indication of a non-binauralization process associated with processed spatial position information, which is binary data indicating a single channel of the audio headset (E200), the audio mono signal is directed (O-E200) to a stereo processor and / or mixing module which takes into account the processed spatial position information to construct (E220) two processed channels, said two processed channels being directly processed in a direct mixing step (E230) in which said two processed channels are summed with a binaural signal resulting from a binauralization process for processing by the audio headset (E240), the audio mono signal is a channel type signal that is directed to the stereo processor and / or the mixing module together with the processing spatial position information; method.

2. A method for processing an audio mono signal in a 3D audio decoder, comprising the step of performing a binauralization process on a signal decoded for spatial processing by an audio headset, comprising: Upon detecting in the data stream representative of the audio mono signal an indication of a non-binauralization process associated with processed spatial position information, which is binary data indicating a single channel of the audio headset (E200), the audio mono signal is directed (O-E200) to a stereo processor and / or mixing module which takes into account the processed spatial position information to construct (E220) two processed channels, said two processed channels being directly processed in a direct mixing step (E230) in which said two processed channels are summed with a binaural signal resulting from a binauralization process for processing by the audio headset (E240), the audio mono signal is an object-type signal associated with a set of processing parameters including the instructions for the de-binauralization processing and the processing spatial position information, the signal being directed to the stereo processor and / or blending module together with the processing spatial position information; method.

3. 2. The method of claim 1, wherein only the processed channels corresponding to the channels indicated by the binary data are summed with the corresponding channels of the binaural signal in the direct mixing step, and the values ​​of other processed channels are null.

4. An apparatus for processing a mono audio signal, comprising: a module for performing binaural processing on a signal decoded for spatial processing by an audio headset, a detection module (330; 430) capable of detecting, in a data stream representative of said audio mono signal, an indication of a de-binauralization process associated with processed spatial position information, said processed spatial position information being binary data representative of a single channel of said audio headset; a transfer module (330, 430) capable of directing said audio mono signal to a stereo processor and / or a mixing module in case of a successful detection by said detection module; a stereo processor (331; 431) and / or a mixing module (340; 440) capable of constructing two processing channels taking into account said processing spatial position information, a mixing module (340; 440) capable of directly processing the two processing channels, by summing them with a binaural signal generated by a module performing a binauralization process (320; 420), for processing by said audio headset.

5. The apparatus of claim 4 , wherein the stereo processor is incorporated into the mixing module.

6. 5. The apparatus of claim 4, wherein the audio mono signal is a channel type signal and the stereo processor is integrated into a channel processor that further constructs processing channels for a multi-channel signal.

7. 5. The apparatus of claim 4, wherein the audio mono signal is an object type signal, and the stereo processor is incorporated into an object processor that further constructs a processing channel for the audio mono signal associated with a set of processing parameters.

8. An audio decoder including a processing device according to any one of claims 4 to 7.

9. A computer program comprising code instructions which, when executed by a processor, performs the steps of the processing method according to any one of claims 1 to 3.

10. A processor-readable storage medium storing a computer program comprising instructions for carrying out the processing method according to any one of claims 1 to 3.

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