Method and an apparatus for system encoding bitstreams for seamless connection

Abstract

An encoding method for producing specific encoded data by calculating the data occupancy of a decoding buffer memory of a particular size that is used when decoding the encoded data during reproduction, defining the allocated code size of a particular period based on the calculation result, and compression coding the signal of a particular period to the allocated code size. The data occupancy is calculated on the assumption that virtual encoded data is transferred to the decoding buffer memory following the transfer of the first-encoded data to the decoding buffer memory. The data occupancy when the last data in the first encoded data is decoded is calculated as the final buffer occupancy Be. The data occupancy when the encoding process producing the second encoded data is begun is an initial buffer occupancy Bi where the initial buffer occupancy Bi is less than the final buffer occupancy Be, and thus allocated code size is defined based on the change in the data occupancy.

Description

BACKGROUND OF THE INVENTION1. Field of the InventionThe present invention relates to a method and apparatus for system encoding bitstreams for seamless connection and, more specifically, to bitstreams for use in an authoring system for variously processing a data bitstream comprising the video data, audio data, and sub-picture data constituting each of plural program titles containing related video data, audio data, and sub-picture data content to generate a bitstream from which a new title containing the content desired by the user can be reproduced, and efficiently recording and reproducing the generated bitstream using a particular recording medium.2. Description of the Prior ArtAuthoring systems used to produce program titles comprising related video data, audio data, and sub-picture data by digitally processing, for example, multimedia data comprising video, audio, and sub-picture data recorded to laser disk or video CD formats are currently available.Systems using Video-CDs in...

AI Technical Summary

Benefits of technology

Furthermore, by interrupting data transfer to the video buffer 2600 for a predefined time at the connection point between the encoded data streams of the video groups, the reproduction method of the present invention can begin the decoding process when the data occupancy of the video buffer 2600 equals the initial buffer occupancy Bi value set during encoding, and decoding can proceed with the change in the accumulated video data volume Vdv in the video buffer 2600 varying as expected during encoding. Decoding can therefore proceed without video buffer 2600 failure.

Moreover, if the streams are produced by means of the encoding method and encoding apparatus of the invention, the accumulated video data volume Vdv during decoding can always be calculated during encoding even if streams are connected and contiguously decoded. As a result, it is simpler to interleave the streams with consideration given to synchronization with audio and other data types.

The code size control method controlling the produced code size to within a defined limit shall not be limited to the method described above, and may, for example, control signal quantization parameters to control the code size.

Furthermore, while the embodiments have been described using an optical disk recording medium, the invention shall not be so limited and magnetic disks, magnetic tape, and other recording media can be used.

The encoding method and encoding apparatus of the invention can thus contiguously decode and seamlessly reproduce a smoothly connected reproduction signal without video buffer 2600 failure even when the encoded data streams of plural video groups are connected at user-defined points.

Furthermore, the final buffer occupancy Be and initial buffer occupancy Bi values do not need to be equal at the stream connection points, and code size can be easily controlled insofar as the final buffer occupancy Be is greater than initial buffer occupancy Bi.

Furthermore, by interrupting data transfer to the video buffer 2600 for a predefined time at the connection point between the encoded data streams of the video groups, the reproduction method of the present invention can begin the decoding process when the data occupancy of the video buffer 2600 equals the initial buffer occupancy Bi value set during encoding, and decoding can proceed with the change in the accumulated video data volume Vdv in the video buffer 2600 varying as expected during encoding. Decoding can therefore proceed without video buffer 2600 failure.

When encoded data streams obtained by encoding plural video groups are reproduced by means of the reproduction apparatus of the invention, different streams can be connected, contiguously decoded, and smooth video presentation can be obtained if the streams are encoded so that the accumulated video data volume Vdv in the video buffer 2600 at the end of decoding each stream is greater than a specified data occupancy Bt, which is greater than the accumulated video data volume Vdv at the decoding start.

The encoding method and encoding apparatus of the invention can contiguously decode and seamlessly reproduce a smoothly connected reproduction signal without video buffer failure even when the encoded data streams of plural video groups are connected at user-defined points.

Furthermore, by interrupting data transfer to the video buffer 2600 for a predefined time at the connection point between the encoded data streams of the video groups, the reproduction method of the present invention can begin the decoding process when the data occupancy of the video buffer 2600 equals the initial buffer occupancy Bi value set during encoding, and decoding can proceed with the change in the accumulated video data volume Vdv in the video buffer 2600 varying as expected during encoding. Decoding can therefore proceed without video buffer 2600 failure.

When encoded data streams obtained by encoding plural video groups are reproduced by means of the reproduction apparatus of the invention, different streams can be connected, contiguously decoded, and smooth video presentation can be obtained if the streams are encoded so that the accumulated video data volume Vdv in the video buffer 2600 at the end of decoding each stream is greater than a specified data occupancy Bt, which is greater than the accumulated video data volume Vdv at the decoding start.

Problems solved by technology

The problem is that the mechanical strength of the disk is low when the transparent substrate is very thin.

As described above, it is therefore not possible in a conventional authoring system to process a large data stream containing sufficient information to satisfy many different user requirements.

Moreover, even if such a processing method were available, the processed data recorded thereto cannot be repeatedly used to reduce data redundancy because there is no large capacity recording medium currently available that can efficiently record and reproduce high volume bitstreams such as described above.

Unselected multi-scene data is therefore unavoidably inserted between the selected common scene data and the selected multi-scene data.

The problem this creates when reproducing multi-scene data is that reproduction is interrupted by this unselected scene data.

A further problem can be expected when the multi-scene data is multi-angle scene data, i.e., scene data showing substantially the same subject from different angles.

Specifically how these plural video streams will be connected and reproduced, however, cannot be determined during the encoding process.

As a result, the behavior of the decoder video buffer, specifically the data accumulation state of the video buffer during the decoding process, cannot be determined during the encoding process.

As a result, a video buffer overflow or underflow state may occur during decoding.

Even at one-to-one connections between common scenes (system streams), the behavior of the decoder video buffer cannot be determined during encoding.

This makes it necessary to control the sequence of the coding process, and limits the flexibility of the title production process.

Because it is therefore difficult to accurately limit the encoded data size to a specific, predetermined size, it is difficult to accurately specify the final buffer occupancy.

It is therefore difficult to assure that the final decode video buffer occupancy is the same with each of plural video streams.

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