[FFmpeg-devel] probable dshow bug or strangeness

[Don Moir]

> ----- Original Message ----- 
> From: "Michael Niedermayer" <michaelni at gmx.at>
> To: "FFmpeg development discussions and patches" <ffmpeg-devel at ffmpeg.org>
> Sent: Thursday, March 13, 2014 1:33 PM
> Subject: Re: [FFmpeg-devel] probable dshow bug or strangeness
>
>>
>> I also wonder what this "i420" mentioned by VLC even is, maybe our
>> list_options output here is not verbose enough?
>>
>>
>> I still wonder what values VLC is getting back from
>> GetActualDataLength...or if it has a work around :)
>>
>>> 2 other things though. These don't have have anything to do with zero length
>>> problem.
>>>
>>> 1)
>>>
>>> static enum AVPixelFormat dshow_pixfmt(DWORD biCompression, WORD
>>> biBitCount)
>>> {
>>>     switch(biCompression) {
>>>     case BI_BITFIELDS:
>>>     case BI_RGB:
>>>         switch(biBitCount) { /* 1-8 are untested */
>>>             case 1:
>>>                 return AV_PIX_FMT_MONOWHITE;
>>>             case 4:
>>>                 return AV_PIX_FMT_RGB4;
>>>             case 8:
>>>                return AV_PIX_FMT_RGB8;
>>>             case 16:
>>>                return AV_PIX_FMT_RGB555;
>>>             case 24:
>>>                return AV_PIX_FMT_BGR24;
>>>             case 32:
>>> -                return AV_PIX_FMT_RGB32;
>>> +                return AV_PIX_FMT_0RGB32;
>>>         }
>>>     }
>>>     return avpriv_find_pix_fmt(ff_raw_pix_fmt_tags, biCompression); // all
>>> others
>>> }
>>>
>>> BI_RGB is assumed to opaque and not alpha. The alpha is hidden in
>>> AV_PIX_FMT_RGB32. It should have been named AV_PIX_FMT_ARGB32 and
>>> opaque should have been named AV_PIX_FMT_XRGB32 to avoid confusion.
>>
>>
>>LGTM.

>if theres some patch i should apply, please someone provide
>one with a commit message (for git am)

At least 3 patches are going to be needed to be applied for dshow code. 2 are straight forward and one(or more) is not determined 
yet. The 2 that are known need to put up properly of course. Just finding these things as we look into a more serious problem and so 
far just put up as notification as an aid for anyone trying to test the 3 problem that might run into these things.