On Wed, 12 Mar 2014 21:18:46 +0100, wm4 <[email protected]> wrote:
> mp4 files embedding DVD subtitles do not use the same extradata format
> as the rest of Libav expects. The subtitle decoder in libavcodec in
> particular does not understand this format.
> 
> Convert the extradata to the vobsub .idx format. mp4 stores the palette
> as binary 32 bit ints in YUV. The subtitle resolution is stored
> separately in the track header, which we access through AVStream.
> ---
> Some uncertainties:
> - not sure if I got the component order right, and all samples I
>   found had gray subs
> - should this write a header? Like:
>    # VobSub index file, v7 (do not modify this line!)
> - is the width/height necessarily known at this point? the size comes
>   from the "tkhd" element, and it looks like in theory it doesn't need
>   to come before the other elements.
> 
> Also, I tried to use libavutil/colorspace.h for the colorspace
> conversion. But it's so messy, and ff_cropTbl (needed for using it
> comfortably) is private to libavcodec. So I just copied the YUV
> to RGB conversion from some site.
> ---
>  libavformat/isom.c | 57 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 57 insertions(+)
> 

LGTM, pushed
Thanks

-- 
Anton Khirnov
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