[FFmpeg-devel] [PATCH] Make FFmpeg recognize QT version 0 sound sample descriptions and store the palette in matroskadec.c

Mats Peterson matsp888 at yahoo.com
Fri Dec 11 02:00:35 CET 2015

It's not replacing the private data at all.It allocates extradata separately from it. No program I know of uses this extradata *in Quicktime video in Matroska using a palette* for anything but tacking the palette onto a BITMAPINFOHEADER, like MPlayer. This is by far the best solution to make MPlayer recognize the palette in a QuickTime file, just like it does with V_MS/VFW/FOURCC. The problem is that it can't use an offset into the private data for QuickTime video as it does with V_MS/VFW/FOURCC, since the QT video often doesn't have any palette in the private data, has to get the default Macintosh palette. It's not my hack for the record. But it's a hack that works.
Mats Peterson
      From: Hendrik Leppkes <h.leppkes at gmail.com>
 To: FFmpeg development discussions and patches <ffmpeg-devel at ffmpeg.org> 
 Sent: Friday, December 11, 2015 1:53 AM
 Subject: Re: [FFmpeg-devel] [PATCH] Make FFmpeg recognize QT version 0 sound sample descriptions and store the palette in matroskadec.c
On Thu, Dec 10, 2015 at 12:06 PM, Mats Peterson
<matsp888-at-yahoo.com at ffmpeg.org> wrote:
> I've attached a unified diff of the latest Git version of matroskadec.c that does two things:
> 1. It allows FFmpeg to recognize QuickTime version 0 sound sample descriptions by using 36 instead of 86 as the minimum private data size for A_QUICKTIME.
> 2. The palette, in QuickTime video that has one, is put in extradata, to make MPlayer recognize it and tack it to the end of its "fake" BITMAPINFOHEADER.
> This patch is an improvement and tidying-up of a proposed patch by Martin Storsjö, for the record. The version 0 sound sample description stuff is made by me long ago, though.

This is an extremely ugly hack. Replacing priv_data and calling into
the mov demuxer? Rather come up with a better solution without the
potential for a whole load of side-effects.

- Hendrik

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