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

Michael Niedermayer michaelni
Thu Jun 3 23:25:05 CEST 2010

On Thu, Jun 03, 2010 at 02:22:48PM -0700, Baptiste Coudurier wrote:
> On 06/03/2010 02:16 PM, Michael Niedermayer wrote:
>> 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,
>> done
>>> 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
> Whatever, I'm against this name, stefano as well.
> Shall we start a vote ?

yes of course ;)
but first we should wait 48h for people to propose options

currently we have


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Into a blind darkness they enter who follow after the Ignorance,
they as if into a greater darkness enter who devote themselves
to the Knowledge alone. -- Isha Upanishad
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