Incorrect channel mapping for 8-channel audio in ffmpeg_aac_bitstream_converter
Reported by
jwalc...@opera.com,
Aug 24 2016
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Issue description
UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/51.0.2704.79 Chrome/51.0.2704.79 Safari/537.36
Example URL:
Steps to reproduce the problem:
Logic in fmpeg_aac_bitstream_converter.cc, specifically in GenerateAdtsHeader() incorrectly maps FFmpeg 8-channel audio to ATDS 8-channel audio.
Currently there is:
case 7:
// front-center, front-left, front-right, side-left, side-right,
// back-left, back-right, LFE-channel
hdr[2] |= 1;
hdr[3] |= (3 << 6);
break;
But there should be:
case 8:
// front-center, front-left, front-right, side-left, side-right,
// back-left, back-right, LFE-channel
hdr[2] |= 1;
hdr[3] |= (3 << 6);
break;
What is the expected behavior?
What went wrong?
The mapping is incorrect
Did this work before? N/A
Is it a problem with Flash or HTML5? N/A
Does this work in other browsers? N/A
Chrome version: Channel: n/a
OS Version:
Flash Version:
FFmpeg's AVCodecContext->channels contains "raw number of channels" (e.g. 8 for 8 channels) instead of "MPEG-4 Channel Configuration (e.g. 7 aka 0b111 for 8 channels)".
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Aug 25 2016
,
Aug 25 2016
I will prepare a patch, but I am not sure about ETA.
,
Aug 25 2016
,
Aug 26 2016
The following revision refers to this bug: https://chromium.googlesource.com/chromium/src.git/+/a5cd9c49bcb56a12f04555cc218c4a940a579a4e commit a5cd9c49bcb56a12f04555cc218c4a940a579a4e Author: jwalczak <jwalczak@opera.com> Date: Fri Aug 26 11:16:22 2016 Fix channel mapping for 8-ch audio in ffmpeg_aac_bitstream_converter FFmpeg's AVCodecContext->channels contains "raw number of channels" (e.g. "2" for 2 channels, "8" for 8 channels). The change ensures that: - the value of "8" is correctly mapped to 0b111 ADTS channel config (aka MPEG-4 Channel Configuration), - the value of "7" becomes unsupported. BUG= 640610 Review-Url: https://codereview.chromium.org/2273203003 Cr-Commit-Position: refs/heads/master@{#414685} [modify] https://crrev.com/a5cd9c49bcb56a12f04555cc218c4a940a579a4e/media/filters/ffmpeg_aac_bitstream_converter.cc
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Aug 26 2016
CL is submitted. close this bug. |
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Comment 1 by dalecur...@chromium.org
, Aug 24 2016