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

[Mats Peterson]

On 03/11/2016 03:21 PM, Mats Peterson wrote:
> On 03/11/2016 03:13 PM, Mats Peterson wrote:
>> Michael Niedermayer <michael at niedermayer.cc> skrev: (11 mars 2016
>> 15:05:49 CET)
>>> On Fri, Mar 11, 2016 at 02:12:56PM +0100, Mats Peterson wrote:
>>>> 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/
>>>>>> _______________________________________________
>>>>>> 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/
>>>>> _______________________________________________
>>>>> ffmpeg-devel mailing list
>>>>> ffmpeg-devel at ffmpeg.org
>>>>> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>>>
>>>> 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.
>>>
>>> we didnt invent ASUS video 1 and 2 nor huffyuv
>>>
>>> which codec with a non-palette global header puts 40 there ?
>>>
>>> the ms specs just says the color table & mask isnt part of biSize
>>> it doesnt say the global header isnt, or iam looking at the wrong text
>>> or location in the text/spec
>>>
>>> [...]
>>
>> Again, only one I know of is HuffYUV, and the specs define a custom
>> BITMAPINFOHEADER that includes the Huffman tables. The "global data"
>> in ASUS is only 8 bytes. Do they regard the BITMAPINFOHEADER as being
>> part of this global data as well? And should we? A BITMAPINFOHEADER is
>> a BITMAPINFOHEADER is a BITMAPINFOHEADER...
>>
>> Mats
>>
>
> Do you have a sample file with asv1/asv2 *created by ASUS* where biSize
> isn't 40?
>
> Mts
>

I got the asv1/asv2 samples from the MPlayer sample directory. Are they 
from ASUS? They all use a biSize of 48.

Mats

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