[FFmpeg-devel] [RFC] Request for pixdesc API review

Stefano Sabatini stefano.sabatini-lala
Fri Dec 4 02:03:34 CET 2009


On date Tuesday 2009-11-24 21:30:22 -0500, Ronald S. Bultje encoded:
> Hi,
>
> On Nov 24, 2009, at 8:11 PM, Stefano Sabatini 
> <stefano.sabatini-lala at poste.it> wrote:
>> On date Tuesday 2009-11-24 19:02:17 -0500, Ronald S. Bultje encoded:
>>> Hi,
>>>
>>> On Nov, 2009, at 6:28 PM, Stefano Sabatini
>>> <stefano.sabatini-lala at poste.it> wrote:
>>>> On date Monday 2009-11-23 22:44:57 +0100, Michael Niedermayer  
>>>> encoded:
>>>>> On Mon, Nov 23, 2009 at 09:48:49PM +0100, Stefano Sabatini wrote:
>>>> [...]
>>>>>> Index: ffmpeg/libavutil/pixdesc.h
>>>>>> === 
>>>>>> ================================================================
>>>>>> --- ffmpeg.orig/libavutil/pixdesc.h    2009-11-23
>>>>>> 21:05:53.000000000 +0100
>>>>>> +++ ffmpeg/libavutil/pixdesc.h    2009-11-23 21:21:39.000000000
>>>>>> +0100
>>>>>> @@ -86,7 +86,11 @@
>>>>>>
>>>>>> #define PIX_FMT_BE        1 ///< Pixel format is big-endian.
>>>>>> #define PIX_FMT_PAL       2 ///< Pixel format has a palette in  
>>>>>> data
>>>>>> [1], values are indexes in this palette.
>>>>>> -#define PIX_FMT_BITSTREAM 4 ///< All values of a component are
>>>>>> bit-wise packed end to end.
>>>>>> +/**
>>>>>> + * All values of a component are bit-wise packed end to end, that
>>>>>> is,
>>>>>> + * the bits of the component values are not byte-aligned.
>>>>>
>>>>> i for one dont consider this better
>>>>
>>>> Well then I'd say patch dropped, unless someone else wants to  
>>>> suggest
>>>> something better.
>>>
>>> Data is not byte-aligned per pixel?
>>
>> Yes per pixel they are, but not per pixel component.
>
> There you go, add that and you're done. In fact, now I know what the  
> flag means w/o looking at the code.

Mmmh thinking again at it, saying that "for bitstream formats the bits
composing a pixel are byte-aligned, but the bits composing a component
are not" is neither correct (think at monow/monob) neither
particularly clear, since I can't find better words for describing it
I'll leave the docs as they are.

Regards.
-- 
FFmpeg = Foolish and Furious Mega Puritan Ecumenical Gospel



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