[FFmpeg-devel] [PATCH 1/3] lavf/riffenc: Improve spec compliance

Michael Niedermayer michael at niedermayer.cc
Fri Mar 11 13:14:16 CET 2016


On Fri, Mar 11, 2016 at 05:17:18AM +0100, Mats Peterson wrote:
> On 03/11/2016 05:10 AM, Mats Peterson wrote:
> >Forget patch 2/3 and 3/3 from the old patch set.
> >
> > From the Microsoft documentation for BITMAPINFOHEADER at
> >https://msdn.microsoft.com/en-us/library/windows/desktop/dd318229%28v=vs.85%29.aspx:
> >
> >
> >"biSize: Specifies the number of bytes required by the structure. This
> >value does not include the size of the color table or the size of the
> >color masks, if they are appended to the end of structure."
> >
> >So, biSize is always 40. Also, Windows Media Player won't detect video
> >encoded with Microsoft Video 1 in 8 bpp mode if this value is anything
> >else than 40. I don't know about other codecs, they probably work.
> >Anyway, we should stick with the specs, and not include the palette size
> >in that field.
> >
> >Regarding the biClrUsed field, I'm setting it to 1 <<
> >bits_per_coded_sample if palettized video, since setting it to 0 is
> >another case where it won't work with Windows Media Player and Microsoft
> >Video 1 in 8 bpp mode.
> >
> >Mats
> >
> >
> >
> 
> Once, again, HuffYUV has its own variant of BITMAPINFOHEADER that
> *does* include the size of the Huffman tables in biSize. That's the
> only exception as far as I know.

is huffyuv really the exception ? and not raw rgb or palettes ?

asv1 and asv2 do not have 40 there
which codec with a non-palette global header puts 40 there ?

[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

What does censorship reveal? It reveals fear. -- Julian Assange
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