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

Mats Peterson matsp888 at yahoo.com
Fri Mar 11 09:05:55 CET 2016


On 03/11/2016 06:43 AM, 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
>>
>>
>>
>
> OK, I missed your "breaks fate" message, Michael. Then we'll have to
> regenerate those fate tests. Can you do it? I'm afraid of messing things
> up.
>
> Mats
>
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I'm regenerating them here. I hope I'm doing it right. If it doesn't 
work, I'll notify you.

Mats

-- 
Mats Peterson
http://matsp888.no-ip.org/~mats/


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