[FFmpeg-devel] [PATCH] grayalpha pixfmt + support in pngdec

Michael Niedermayer michaelni
Thu Jun 3 23:16:51 CEST 2010

On Thu, Jun 03, 2010 at 12:14:58PM -0700, Baptiste Coudurier wrote:
> On 06/03/2010 03:45 AM, Michael Niedermayer wrote:
>> On Wed, Jun 02, 2010 at 05:37:36PM -0700, Baptiste Coudurier wrote:
>>> On 04/18/2010 03:57 PM, Michael Niedermayer wrote:
>>>> On Sun, Apr 18, 2010 at 09:36:22PM +0200, Stefano Sabatini wrote:
>>>>> On date Tuesday 2010-04-13 12:21:47 +0200, Michael Niedermayer encoded:
>>>>>> On Tue, Apr 13, 2010 at 10:34:48AM +0200, Andreas ?man wrote:
>>>>>>> Kostya wrote:
>>>>>>>> On Tue, Apr 13, 2010 at 09:33:51AM +0200, Andreas ?man wrote:
>>>>>>>>> Michael Niedermayer wrote:
>>>>>>>>>> On Mon, Apr 12, 2010 at 09:40:03PM +0200, Andreas ?man wrote:
>>>>>>>>>>> Michael Niedermayer wrote:
>>>>>>>>>>>> On Mon, Apr 12, 2010 at 10:43:02AM +0200, Andreas ?man wrote:
>>>>>>>>>>>>> Hi
>>>>>>>>>>>>> +    [PIX_FMT_GRAYALPHA] = {
>>>>>>>>>>>>> +        .name = "grayalpha",
>>>>>>>>>>>> where does the name grayalpha come from?
>>>>>>>>>>> I just didn't come up with anything better.
>>>>>>>>>>> Ideas are most welcome.
>>>>>>>>>> something that is consistent with existing formats would
>>>>>>>>>> be better also what is it calld in the png docs?
>>>>>>>>> PNG docs seems to call it "Grayscale with alpha" or "ya".
>>>>>>>>> Perhaps "ya" would be a good name then?
>>>>>>>> Nej, it obviously stands for "Y(aka luma) + A(alpha)"
>>>>>>>> i.e. not so good acronym.
>>>>>>> Kostya suggested "Y400A" on IRC.
>>>>> I'm not very happy with this name, "4XX" notation only makes sense
>>>>> when we have three components, in this case I would have preferred
>>>>> something of the kind GRAY8ALPHA8 or GRAYALPHA8 (consistent with
>>>>> GRAY8), even YA was not that bad.
>>>> GRAY*ALPHA* is inconsistent with the existing naming and gray8 is quite
>>>> alone and the exception, not a good example to copy.
>>>>> Not that I consider this a big issue, we will eventually fix the names
>>>>> at the next major bump.
>>>> The naming is good and reasonable consistent. To change it at the next 
>>>> maj
>>>> ver
>>>> bump there needs to be a problem in the existing naming and a better
>>>> naming and
>>>> consensus amongth the devels that the new is better and not just the
>>>> yearly
>>>> bikeshed style. Because every such change means everyone will have to
>>>> update
>>>> their applications and this is a lot of work when one considers how many
>>>> applications there are. Not to mention the ones that try to support
>>>> differnent
>>>> lav* versions
>>> I need to revive this thread since I've come up with a file that I want
>>> supported.
>>> I disagree, Y400A is a very bad name since the gray plane is coded using
>>> 0-255 and IMHO is not really similar to a Y plane IMHO in the YUV sense, 
>>> if
>>> you want to call it Y then YJ400A at least.
>> the luma range, really is indicated by AVCodecContext.color_range
>> the J pixel formats are deprecated.
> Then mark them as so,


> and start changing the code, because I would 
> personally not remove something that has been in the code so long ;)

changing lavc is not hard but applications need to be changed too
and i just now marked it as deprecated ...
maybe we can add YJ400A as an intermediate workaround because the other
formats where not correctly marked as deprecated as i thought they where


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Many that live deserve death. And some that die deserve life. Can you give
it to them? Then do not be too eager to deal out death in judgement. For
even the very wise cannot see all ends. -- Gandalf
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