[FFmpeg-devel] [PATCH 1/2] lavf/riffenc: Improve spec compliance; Fix WMP playback of AVI with xxpc chunks
matsp888 at yahoo.com
Sun Mar 13 06:23:05 CET 2016
On 03/13/2016 06:15 AM, Mats Peterson wrote:
> On 03/12/2016 07:12 AM, Mats Peterson wrote:
>> New patch set. Forget the old one.
>> From the Microsoft documentation for BITMAPINFOHEADER at
>> "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));
This one is better:
avio_wl32(pb, 40 + (ignore_extradata || pal_avi ? 0 : extradata_size);
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