JP2007058128A - Bitstream decoding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bitstream decoding device that generates a normal speech output while suppressing an abnormal speech output when a nonstandardized bitstream is decoded, and increases user's convenience. <P>SOLUTION: Even if an input bitstream is nonstandardized, a decoder unit 201 generates PCM data by performing decoding processing while permitting the bitstream to be nonstandardized. A decoding result analysis unit 202 analyzes the decoded PCM data and a control unit 203 controls an output speech based upon the analysis result. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a bit stream decoding apparatus that performs decoding processing of an error bit stream.

  In recent AV files, compressed audio and compressed video are mainly used. Also, with the spread of personal computers, it has become possible for users to easily author AV files. For this reason, various manufacturers sell authoring software and encoders, and there are countless numbers of shareware, free software, etc. that are available on the Internet. However, the quality of the encoder varies, and there is software that performs encoding that violates operational standards.

  When decoding a bitstream created using an encoder that violates such standards, for example, if error processing is performed when violation parameters exist in the bitstream, the violation When a parameter does not affect the decoding process or when a correct parameter is determined from another parameter, there is a problem that although a normal output is obtained, it is processed as an error and an output cannot be obtained.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a method in which violation parameters are allowed and error processing is not performed, but default parameters are used instead.

  FIG. 1 is a block diagram showing a configuration of a conventional bitstream decoding apparatus. Hereinafter, as an example, a case where there is an error in the audio bitstream will be described.

  As shown in FIG. 1, an error bit stream such as a standard violation is read by the decoder unit 101 and output to the error processing unit 102.

  Here, when an error bit stream is processed as an error, the error processing unit 102 performs MUTE processing, and audio data of 0 data is output.

When an error in the error bit stream is allowed, the decoder unit 101 is forcibly decoded.
JP 2004-7359 A

  However, the conventional bitstream decoding device can obtain a normal audio output if it can be correctly decoded even if it is a violation bitstream, but outputs an abnormal audio output if it cannot be decoded correctly. There was a problem that.

  The present invention has been made in view of this point, and the object of the present invention is to output a bitstream that violates the standard when it is determined that a normal output can be obtained. There is.

That is, in the present invention, a bitstream decoding device that decodes a coded video or audio data bitstream according to a predetermined standard,
Decoding means for decoding the bitstream;
Decoding result analysis means for analyzing the information decoded by the decoding means;
Control means for controlling the decoding means to perform predetermined processing on the bitstream when the bitstream is determined to be in violation of the standard based on the analysis result of the decoding result analysis means. It is characterized by.

  As described above, according to the present invention, when decoding a bitstream that violates the standard, normal audio output can be obtained while suppressing abnormal audio output, and user convenience is improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or its application.

<Embodiment 1>
FIG. 2 is a block diagram showing the configuration of the bitstream decoding apparatus according to Embodiment 1 of the present invention. Hereinafter, a case where there is an error in the audio bitstream will be described as an example. The same applies to the following second and third embodiments.

  As shown in FIG. 2, the decoder unit 201 receives a bit stream and decodes the encoded data in the bit stream. Here, even if the bit stream is in violation of the standard, the decoder unit 201 performs decoding processing while allowing the violation, and generates PCM data (Pulse Code Modulation).

  Here, as a method of allowing the violation of the standard, for example, the parameter of the current frame is predicted based on the parameter of the previous frame, the default value is set, the decoding process is performed with the value, and the decoding process is performed. If the parameter is not affected, it can be ignored. The PCM data decoded by any method is sent to the decoding result analysis unit 202.

  The decoding result analysis unit 202 analyzes PCM data output from the decoder unit 201, and the analysis result is output to the control unit 203.

  Here, as the analysis means in the decoding result analysis unit 202, means for performing based on a user operation, means for analyzing externally output audio data with an external analysis device, means for analyzing with an internal analysis device before outputting the audio Any analysis means may be used.

  Specifically, in the analysis means based on the user's operation, the user actually listens to the sound data, and the user himself / herself determines whether the sound is normal sound or abnormal sound, and the determination result is analyzed by the decoding result The data is transmitted to the unit 202.

  Further, in the analysis means using the external analysis device, the output sound data is analyzed by a sound analysis device (not shown) provided outside the bit stream decoding device, thereby determining whether the sound is normal sound or abnormal sound. The determination result is transmitted to the decoding result analysis unit 202.

  Further, the analysis means using the internal analysis device performs spectrum analysis of the PCM data output from the decoder unit 201 before outputting the audio data to the outside, and is a normal sound based on the spectrum analysis result. Or abnormal sound.

  The control unit 203 controls the output of the decoded audio data. Specifically, when the decoding result analysis unit 202 determines that the sound is normal, control is performed so that the PCM data is output as it is.

  On the other hand, when the decoding result analysis unit 202 determines that the sound is abnormal, it performs MUTE processing, SKIP processing, PCM data prediction value interpolation processing, etc. on the PCM data, and outputs the processed PCM data Control to do.

  By performing such processing, it is possible to reproduce an error bit stream that provides a normal output.

  In the case where the analysis means in the decoding result analysis unit 202 is analysis based on the user's operation, the audio data is taken into consideration that the audio output is abnormal and may cause discomfort to the user. It is also possible to perform processing such as lowering the gain of the output or limiting the output time of the audio data. In this way, an advantageous effect can be obtained in suppressing user discomfort.

  Further, when the analysis result of the decoding result analysis unit 202 is abnormal and the creation source of the bitstream is known, the fact that the encoder is abnormal is notified to the creation source via, for example, the Internet. It is also possible to perform processing such as notification and requesting correction.

  Information analyzed by the decoding result analysis unit 202 is output to the error information storage unit 204. The error information storage unit 204 stores error information. For example, when the same bit stream is reproduced next time, the stored error information is not analyzed without analyzing the decoding result of the bit stream. By reading, the decoding process can be normally performed.

  As described above, according to the bitstream decoding apparatus according to the first embodiment, when decoding a noncompliant bitstream, normal audio output can be obtained while suppressing abnormal audio output, and user's Convenience increases.

<Embodiment 2>
FIG. 3 is a block diagram showing the configuration of the bitstream decoding apparatus according to Embodiment 2 of the present invention. As shown in FIG. 3, the decoder unit 301 receives a bit stream and decodes encoded data in the bit stream.

  Here, in the decoder unit 301, even if the bit stream is in violation of the standard, the violation is allowed and the decoding process is performed to create PCM data. As a method for allowing a standard violation, the method exemplified in the first embodiment can be considered. The PCM data decoded by any method is sent to the decoding result analysis unit 302.

  The decoding result analysis unit 302 analyzes the PCM data output from the decoder unit 301 and outputs the analysis result to the bit stream correction unit 303.

  Here, the analysis in the decoding result analysis unit 302 can be performed using the same method as in the first embodiment.

  The bit stream correction unit 303 corrects the bit stream based on the analysis result of the decoding result analysis unit 302.

  Here, as a correction method in the bit stream correction unit 303, for example, the bit stream is re-encoded, corrected using the temporary parameter value used in the decoder unit 301, or the error information of the encoder is changed to the bit stream. It is possible to notify the creator and submit a correction request.

  Then, the correction result in the bit stream correction unit 303 is transmitted to the decoder unit 301.

  However, even if the bitstream is corrected by the bitstream correction unit 303, the decoding result analysis unit 302 may determine that the sound is abnormal again. In this case, it is preferable to repeat the process of correcting and re-decoding the parameter that seems to be an error until the decoding result analysis unit 302 determines that the sound is normal.

  By performing such processing, if the bit rate standard violation is slight, it can be easily corrected to a normal bit stream.

  As described above, according to the bitstream decoding apparatus according to the second embodiment, it is possible to correctly correct and reproduce an error bitstream from which a normal output can be obtained, which increases user convenience.

<Embodiment 3>
FIG. 4 is a block diagram showing the configuration of the bitstream decoding apparatus according to Embodiment 3 of the present invention. As shown in FIG. 4, the decoder unit 401 receives a bit stream and decodes encoded data in the bit stream. Here, in the decoder unit 401, even if the bit stream violates the standard, the violation is allowed and the decoding process is performed to create PCM data. As a method for allowing a standard violation, the method exemplified in the first embodiment can be considered. The PCM data decoded by any method is sent to the error processing unit 402.

  The error processing unit 402 performs error processing on the input PCM data, and allowable error processing is specified by the allowable error specifying unit 403.

  The allowable error specifying unit 403 is for specifying an error that can be allowed by the user. Specifically, various error allowable levels such as MUTE processing, SKIP processing, and nothing can be specified. It has become.

  Increasing the error tolerance level increases the number of bitstreams that can be played, but the possibility that the output sound will be abnormal will increase, and if the error tolerance level is lowered, the possibility of outputting abnormal noise will be reduced. Since the bit stream that can be reproduced is reduced, it is necessary to set an appropriate error tolerance level according to the user's preference.

  As described above, according to the bit rate decoding apparatus according to the third embodiment, it is possible to set an error level that can be allowed by the user, and to realize an appropriate reproduction environment according to the user's preference.

  Of course, the bit rate decoding apparatus according to the first to third embodiments can similarly perform error processing of a bit stream including video data.

  As described above, the present invention provides a highly practical effect that normal output data can be obtained even when the bit stream of audio or video data includes standards violation or error data. It is extremely useful and has high industrial applicability.

It is a block diagram which shows the structure of the conventional bit stream decoding apparatus. It is a block diagram which shows the structure of the bit stream decoding apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the bit stream decoding apparatus which concerns on this Embodiment 2. It is a block diagram which shows the structure of the bit stream decoding apparatus which concerns on this Embodiment 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 201 Decoder part 202 Decoding result analysis part 203 Control part 204 Error information storage part 301 Decoder part 302 Decoding result analysis part 303 Bit stream correction part 401 Decoder part 402 Error processing part 403 Allowable error designation part

Claims (15)

A bitstream decoding device for decoding a bitstream of encoded video or audio data according to a predetermined standard,
Decoding means for allowing the bitstream to be decoded even if the bitstream is in violation of the standard; and
Decoding result analysis means for analyzing the data decoded by the decoding means;
Control means for controlling the decoding means to perform predetermined processing on the bitstream when the bitstream is determined to be in violation of the standard based on the analysis result of the decoding result analysis means. A bit stream decoding device characterized by the above. The bitstream decoding device according to claim 1, wherein
In place of the control means, a bit stream comprising bit stream correction means for correcting the bit stream when the bit stream is determined to be in violation of the standard based on the analysis result of the decoding result analysis means Decoding device. A bitstream decoding device for decoding a bitstream of encoded video or audio data according to a predetermined standard,
Decoding means for allowing the bitstream to be decoded even if the bitstream is in violation of the standard; and
Error processing means for performing error processing on the data decoded by the decoding means;
A bitstream decoding apparatus comprising: an allowable error designating unit for designating error processing permitted by the error processing unit based on a user operation. The bitstream decoding device according to claim 1, wherein
The bit stream decoding apparatus, wherein the decoding result analyzing means is configured to analyze data based on a user operation. The bitstream decoding device according to claim 1, wherein
The bit stream decoding device, wherein the decoding result analysis means is an external analysis device provided outside the device. The bitstream decoding device according to claim 1, wherein
The bit stream decoding device, wherein the decoding result analysis means is an internal analysis device provided inside the device. The bitstream decoding device according to claim 1, wherein
The bitstream is audio data;
The control means reduces the gain of the data decoded by the decoding means when the analysis result is in violation of the standard, and outputs the data when the analysis result is normal. A bitstream decoding device configured as described above. The bitstream decoding device according to claim 1, wherein
The bit stream decoding apparatus, wherein the control means is configured to limit an output time of the decoded data. The bitstream decoding device according to claim 1, wherein
The control means is configured to notify error information indicating a violation of a standard to the encoder of the bitstream as a correction request when the analysis result is a violation of the standard. Bitstream decoding device. The bitstream decoding device according to claim 1, wherein
Error information storage means for storing the analysis result and the bitstream information;
The decoding means is configured to perform a decoding process based on information stored in the error information storage means when the same bit stream as the stored bit stream is input. Bitstream decoding device. The bitstream decoding device according to claim 1, wherein
The control means is configured to perform MUTE processing on the bitstream when the bitstream is determined to be in violation of the standard based on the analysis result of the decoding result analysis means. Bitstream decoding device. The bitstream decoding device according to claim 1, wherein
The control means performs predictive interpolation processing on the decoding result of the error part from the decoding result before and after the error part when the bit stream is determined to be in violation of the standard based on the analysis result of the decoding result analysis part. A bitstream decoding device configured as described above. The bitstream decoding device according to claim 2, wherein
The bitstream correcting unit is configured to re-encode the bitstream when it is determined that the bitstream is normal based on an analysis result of the decoding result analyzing unit. Decoding device. The bitstream decoding device according to claim 2, wherein
The bitstream correcting means is configured to correct an error part in the bitstream to a correct value when it is determined that the bitstream is normal based on an analysis result of the decoding result analyzing means. A featured bitstream decoding apparatus. The bitstream decoding device according to claim 2, wherein
The bitstream correcting means is configured to correct a parameter estimated to be an error part in the bitstream when the bitstream is determined to be in violation of the standard based on the analysis result of the decoding result analyzing means,
The bit stream decoding device, wherein the decoding result analyzing means is configured to perform error analysis again on the corrected bit stream.

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