[FFmpeg-trac] #11321(avcodec:new): dolby digital plus 7.1 defective decoding

[FFmpeg]

#11321: dolby digital plus 7.1 defective decoding
-----------------------------------+-----------------------------------
             Reporter:  Alexander  |                    Owner:  (none)
                 Type:  defect     |                   Status:  new
             Priority:  normal     |                Component:  avcodec
              Version:             |               Resolution:
             Keywords:             |               Blocked By:
             Blocking:             |  Reproduced by developer:  0
Analyzed by developer:  0          |
-----------------------------------+-----------------------------------
Description changed by Alexander:

Old description:

> Greetings.
> Summary of the bug:
> I found out that the decoding of ddp 7.1 and ddp 7.1 joc is defective. It
> looks like the audio data frames from one channel are dropping out into
> the other channels. It happens in random places. This can be clearly seen
> in the spectrogram, zooming in on a given defect location shows the
> absence of signal in one channel and the presence of it in another.  It
> can be clearly audible as clicks on separate channels, but may not be
> audible when listening on the player in stereo downmix. The defect
> appears on all versions of ffmpeg with libavcodec decoder higher than
> 59.37.100.
> How to reproduce:
> {{{
> ffmpeg-master-latest-win64-gpl\bin>ffmpeg.exe -drc_scale 0 -i
> "sample.eac3" -c pcm_s24le "sample.wav"
> ffmpeg version N-117868-gecc7d5db9c-20241123
> libavcodec     61. 25.102 / 61. 25.102
> }}}
> How to reproduce:
> {{{
> ffmpeg-n7.1-latest-win64-gpl-7.1\bin>ffmpeg.exe -drc_scale 0 -i
> "sample.eac3" -c pcm_s24le "sample_n7.1.wav"
> ffmpeg version n7.1-36-g20c8a3f5ff-20241123
> libavcodec 61. 19.100 / 61. 19.100
> }}}
> How to reproduce:
> {{{
> ffmpeg-n6.1-latest-win64-gpl-6.1\bin>ffmpeg.exe -drc_scale 0 -i
> "sample.eac3" -c pcm_s24le "sample_n6.1.wav"
> ffmpeg version n6.1.2-15-ga6a07eebdf-20241123
> libavcodec 60. 31.102 / 60. 31.102
> }}}
> How to produce **correct results without defects:**
> {{{
> ffmpeg-n5.1-latest-win64-lgpl-5.1\bin>ffmpeg.exe -drc_scale 0 -i
> "sample.eac3" -c pcm_s24le "sample_n5.1.wav"
> ffmpeg version n5.1.6-11-gcde3c5fc0c-20241123
> libavcodec 59. 37.100 / 59. 37.100
> }}}
> Screenshots of defects:
> {{{
> https://drive.google.com/file/d/1fYKmj9YUl3Zpz171mo57Taq81-rrI-
> iP/view?usp=sharing
> https://drive.google.com/file/d/157jC97KsJdpnwH0hh-SjFJtS-
> T4BBVDD/view?usp=sharing
> https://drive.google.com/file/d/1iVZAGU6iSpcE6bc3ZukQMJrcfSQiyNUg/view?usp=sharing
> https://drive.google.com/file/d/1SBQR9wY1-OaXnJEs_wz6r5VktmhUvAJF/view?usp=sharing
> }}}
> eac3 7.1 sample:
> {{{
> https://drive.google.com/file/d/1H78XIQCBHg9YIj8gpcXWJ4uAVqGvI0sz/view?usp=sharing
> }}}

New description:

 Greetings.
 Summary of the bug:
 I found out that the decoding of ddp 7.1 and ddp 7.1 joc is defective. It
 looks like the audio data frames from one channel are dropping out into
 the other channels. It happens in random places. This can be clearly seen
 in the spectrogram, zooming in on a given defect location shows the
 absence of signal in one channel and the presence of it in another.  It
 can be clearly audible as clicks on separate channels, but may not be
 audible when listening on the player in stereo downmix. The defect appears
 on all versions of ffmpeg with libavcodec decoder higher than 59.37.100.
 How to reproduce:
 {{{
 ffmpeg-master-latest-win64-gpl\bin>ffmpeg.exe -drc_scale 0 -i
 "sample.eac3" -c pcm_s24le "sample.wav"
 ffmpeg version N-117868-gecc7d5db9c-20241123
 libavcodec     61. 25.102 / 61. 25.102
 }}}
 How to reproduce:
 {{{
 ffmpeg-n7.1-latest-win64-gpl-7.1\bin>ffmpeg.exe -drc_scale 0 -i
 "sample.eac3" -c pcm_s24le "sample_n7.1.wav"
 ffmpeg version n7.1-36-g20c8a3f5ff-20241123
 libavcodec 61. 19.100 / 61. 19.100
 }}}
 How to reproduce:
 {{{
 ffmpeg-n6.1-latest-win64-gpl-6.1\bin>ffmpeg.exe -drc_scale 0 -i
 "sample.eac3" -c pcm_s24le "sample_n6.1.wav"
 ffmpeg version n6.1.2-15-ga6a07eebdf-20241123
 libavcodec 60. 31.102 / 60. 31.102
 }}}
 How to produce **correct results without defects:**
 {{{
 ffmpeg-n5.1-latest-win64-lgpl-5.1\bin>ffmpeg.exe -drc_scale 0 -i
 "sample.eac3" -c pcm_s24le "sample_n5.1.wav"
 ffmpeg version n5.1.6-11-gcde3c5fc0c-20241123
 libavcodec 59. 37.100 / 59. 37.100
 }}}

 eac3 7.1 sample:
 {{{
 https://drive.google.com/file/d/1H78XIQCBHg9YIj8gpcXWJ4uAVqGvI0sz/view?usp=sharing
 }}}

--
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/11321#comment:1>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker