[FFmpeg-devel] [PATCH] grayalpha pixfmt + support in pngdec
Michael Niedermayer
michaelni
Mon Jun 7 03:24:58 CEST 2010
On Sun, Jun 06, 2010 at 05:41:04PM -0700, Baptiste Coudurier wrote:
> On 6/6/10 5:33 PM, Michael Niedermayer wrote:
>> On Sun, Jun 06, 2010 at 05:30:57PM -0700, Baptiste Coudurier wrote:
>>> On 6/6/10 5:15 PM, Michael Niedermayer wrote:
>>>> On Sun, Jun 06, 2010 at 02:51:59PM -0700, Baptiste Coudurier wrote:
>>>>> On 6/3/10 2:25 PM, Michael Niedermayer wrote:
>>>>>> 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
>>>>>> YJ400A
>>>>>> GRAY8A
>>>>>> GRAY8ALPHA8
>>>>>> GRAYALPHA8
>>>>>
>>>>> GRAY8A input support in libswscale :)
>>>> [...]
>>>>
>>>>> @@ -1062,6 +1063,14 @@
>>>>> }
>>>>> }
>>>>>
>>>>> +static inline void gray8aToA(uint8_t *dst, const uint8_t *src, long
>>>>> width, uint32_t *unused)
>>>>> +{
>>>>> + int i;
>>>>> + for (i=0; i<width; i++) {
>>>>> + dst[i]= src[2*i];
>>>>> + }
>>>>> +}
>>>>
>>>> extract_even() or yuy2ToY() i think does this
>>>
>>> Indeed, nice :)
>>>
>>>> except that it looks ok, i assume its tested
>>>> swscale_example based testing would be ideal but hard if we only support
>>>> input
>>>> without output
>>>
>>> Ok, so can I rename to GRAY8A ? :)
>>
>> you cannot break ABI/API
>
> This is easy I belive:
> #define Y400A GRAY8A under if version < in pixfmt.h
> ABI is not changed, values are the same.
> Is this right ?
looks so, theres also:
libavutil/pixdesc.c: .name = "y400a",
though
>
>> beyond that i dont really care enough about the color
>
> :)
:)
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Good people do not need laws to tell them to act responsibly, while bad
people will find a way around the laws. -- Plato
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