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

Baptiste Coudurier baptiste.coudurier
Thu Jun 3 23:22:48 CEST 2010

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 ?

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