Hi,

On Sun, Oct 14, 2012 at 1:39 PM, Luca Barbato <[email protected]> wrote:
> On 10/14/2012 09:54 PM, Ronald S. Bultje wrote:
>> Hi,
>>
>> On Sun, Oct 14, 2012 at 12:53 PM, Ronald S. Bultje <[email protected]> 
>> wrote:
>>> Hi,
>>>
>>> On Sat, Oct 13, 2012 at 11:13 PM, Ronald S. Bultje <[email protected]> 
>>> wrote:
>>>> Hi,
>>>>
>>>> On Sat, Oct 13, 2012 at 11:06 PM, Luca Barbato <[email protected]> wrote:
>>>>> ---
>>>>>
>>>>> Here an initial patch to support many yuva, apparently either I botched
>>>>> adding them (since I did lots of cut and paste) or they manage the expose 
>>>>> some
>>>>> flaws in swscale. valgrind manages to spot something and might be nice if
>>>>> other people try this and see if the values for the fate-lavfi change 
>>>>> after
>>>>> each round.
>>>>
>>>> If this is what I think it is, search for YUVA420P in swscale and
>>>> replace it with a generic alpha check.
>>>
>>> Oh I see now.
>>>
>>> swscale.c:661
>>>     if (isPlanar(dstFormat) && isALPHA(dstFormat) && !alpPixBuf)
>>>         fillPlane(dst[3], dstStride[3], dstW, dstY - lastDstY, lastDstY, 
>>> 255);
>>> This only works for 8bit. For 9bit, you need a word fill with a value
>>> of (1 << numbits) - 1.
>>
>> Which actually leads to a question: does any of this exist in the real
>> world? I've never, ever, ever seen an image with non-8bpc alpha
>> planes. I hate to invent stuff that has no utility but does carry
>> implementation burden.
>
> You asked me to add those ^^;

Uhm, ok, maybe I meant something else? I mean, there really isn't much
use for 9-15bpp alpha channels as far as I know. 8bpp is obvious and I
can sort of see 16bpp being useful (although I don't think I've ever
seen it used).

> BTW while I was investigating I noticed
> all the previous 9 and 10 formats look strange, if you have time we
> could have a look.

Can you elaborate?

Ronald
_______________________________________________
libav-devel mailing list
[email protected]
https://lists.libav.org/mailman/listinfo/libav-devel

Reply via email to