[FFmpeg-trac] #3256(avformat:open): FFMPEG SVQ3 Matroska remux produces unplayable output (FFPlay don't want to play SVQ3 MKV output)
FFmpeg
trac at avcodec.org
Sun Jan 19 09:13:45 CET 2014
#3256: FFMPEG SVQ3 Matroska remux produces unplayable output (FFPlay don't want to
play SVQ3 MKV output)
-------------------------------------+-------------------------------------
Reporter: Vika | Owner:
Apelsinova | Status: open
Type: defect | Component: avformat
Priority: important | Resolution:
Version: git-master | Blocked By:
Keywords: mkv svq3 | Reproduced by developer: 1
regression |
Blocking: |
Analyzed by developer: 1 |
-------------------------------------+-------------------------------------
Comment (by Vika Apelsinova):
The bug was fixed in MKVToolNix by
https://github.com/mbunkus/mkvtoolnix/commit/6fbbd882d2b0819b2e3a4d4fc2880f94fc985839,
but FFPlay and VLC still don't want to play output.
[[BR]]
> Not really, the output file was invalid (and can not be decoded with
vlc).
Moritz Bunkus a.k.a. mosu wrote:
{{{
That VLC doesn't play audio doesn't mean that mkvmerge is to blame.
Quite the other way around. VLC doesn't support A_QUICKTIME at all.
Just do a recursive grep for A_QUICKTIME on VLC's sources and you'll
see for yourself.
As for the CodecID. mkvmerge has used A_QUICKTIME since 2009. Before
it used A_QUICKTIME/QDMx. Back then there was a decision that
appending the codec type to the A_QUICKTIME string was superfluous as
the FourCC is contained in CodecPrivate for both A_QUICKTIME and
A_QUICKTIME/QDMx. This is very similar to how V_QUICKTIME works. The
CodecPrivate contains the content of the STSD atom.
Unfortunately we totally forgot to update the specs page, which is why
it doesn't list A_QUICKTIME. I will update the specs page tonight.
So if you want to fix ffmpeg you should do the following:
1. In the demuxing part: treat A_QUICKTIME and A_QUICKTIME/wxyz
identically. Get the FourCC from CodecPrivate (should be bytes 4 - 7
starting at 0).
2. In the muxing part: simply don't write A_QUICKTIME/wxyz but just
A_QUICKTIME.
}}}
--
Ticket URL: <https://trac.ffmpeg.org/ticket/3256#comment:6>
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