[FFmpeg-trac] #6983(avcodec:new): AAC encoder breaking 5.1 channels
FFmpeg
trac at avcodec.org
Thu Jan 25 17:53:55 EET 2018
#6983: AAC encoder breaking 5.1 channels
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Reporter: elsiko | Type: defect
Status: new | Priority: normal
Component: avcodec | Version: git-master
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Summary of the bug:
For a long time now, I've been doing some encodings into x265/aac using
ffmpeg.
Recently I started noticing a problem with the audio channels that get - I
think - mixed up.
The original file media info would show:
`Front: L C R, Side: L R, LFE`
But the encoded file will show:
`Front: L C R, Side: C, Back: L R`
I'm no expert, but I think the LFE channel is either dropped or converted.
I think this behaviour started around December 2017.
To be certain that something indeed changed, I encoded a file twice, used
two static builds (from here: https://johnvansickle.com/ffmpeg/), once
using a build from 2017-09-02, and one from 2018-01-24.
I attached to the tickets the logs of both encodings, the media info (+
the original).
You can download the original mkv file, as well as encoded files from
there: http://176.9.126.245/encoding-results/
You can clearly see in the mediainfo of 2017 that the channels were
correct (with LFE), but that's not the case in the 2018 encoding.
One last thing, I think this problem might be related to this ticket:
https://trac.ffmpeg.org/ticket/6965
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Ticket URL: <https://trac.ffmpeg.org/ticket/6983>
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