[FFmpeg-devel] [PATCH 1/2] lavf/riffenc: Improve spec compliance; Fix WMP playback of AVI with xxpc chunks

[Mats Peterson]

On 03/12/2016 07:12 AM, Mats Peterson wrote:
> New patch set. Forget the old one.
>
>  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 40 for palettized video as well. And Windows Media Player
> won't display any video when using Microsoft Video 1 in 8 bpp mode or
> RLE4/RLE8 if this value is set to anything else than 40.
>
> For non-palette extra data in huffyuv, ffvhuff, asv1 and asv2, the extra
> data will be included in biSize. There are possibly more codecs with
> special global headers, but we can fix that as they are discovered.
> Currently these are the only ones I know of.
>

As an alternative to using a list, and as a compromise from my side, is 
the snippet below good enough?

avio_wl32(pb, 40 + (ignore_extradata || pix_fmt == AV_PIX_FMT_PAL8 ?
               0 : extradata_size));

Mats