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

[Mats Peterson]

Mats Peterson <matsp888-at-yahoo.com at ffmpeg.org> skrev: (11 mars 2016 14:06:19 CET)
>Mats Peterson <matsp888-at-yahoo.com at ffmpeg.org> skrev: (11 mars 2016
>13:55:20 CET)
>>Michael Niedermayer <michael at niedermayer.cc> skrev: (11 mars 2016
>>13:49:32 CET)
>>>On Fri, Mar 11, 2016 at 01:28:47PM +0100, Mats Peterson wrote:
>>>> On 03/11/2016 01:25 PM, Mats Peterson wrote:
>>>> >On 03/11/2016 01:14 PM, Michael Niedermayer wrote:
>>>> >>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 ?
>>>
>>>[...]
>>>
>>>> As I said before, Microsoft Video 1 in 8-bit mode and RLE4/RLE8
>>>> won't even display in Windows Media Player if this value is
>anything
>>>> else than 40.
>>>
>>>msv1 / RLE4/8 doesnt have a "Non palette global header"
>>>
>>>
>>>[...]
>>
>>That's correct. Sorry. Anyway, the only case I know of is HuffYUV with
>>its special variant of BITMAPINFOHEADER that includes the Huffman
>>tables. Is there stated anywhere in the ASUS specs that the size of
>the
>>extra data following the BITMAPINFOHEADER should be included in
>biSize?
>>If not, it should be 40.
>>
>>Mats
>>-- 
>>Mats Peterson
>>http://matsp888.no-ip.org/~mats/
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>>ffmpeg-devel mailing list
>>ffmpeg-devel at ffmpeg.org
>>http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
>Those asv1/asv2 files play just fine with a biSize of 40, at that.
>
>Mats
>-- 
>Mats Peterson
>http://matsp888.no-ip.org/~mats/
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>ffmpeg-devel mailing list
>ffmpeg-devel at ffmpeg.org
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Should we perhaps "tighten" the "specs" (I saw that you have written some documentation on asv1/asv2 in FFmpeg), and include those extra bytes in biSize? I suppose this is somewhat of a proprietary FFmpeg invention.

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