[FFmpeg-soc] [soc]: r1932 - libavfilter/vf_scale.c

[Vitor Sessak]

Hi

Bobby Bingham wrote:
> On Sun, 02 Mar 2008 15:00:34 +0100
> Vitor Sessak <vitor1001 at gmail.com> wrote:
>> Bobby Bingham wrote:
>>> On Thu, 28 Feb 2008 00:18:59 +0100 (CET)
>>> koorogi <subversion at mplayerhq.hu> wrote:
>>>
>>>> Author: koorogi
>>>> Date: Thu Feb 28 00:18:58 2008
>>>> New Revision: 1932
>>>>
>>>> Log:
>>>> Slice support for vf_scale.
>>>>
>>>>
>>>> Modified:
>>>>    libavfilter/vf_scale.c
>>>>
>> [...]
>>
>>> After some more testing, it seems this doesn't work right with
>>> --enable-swscaler. I'll take a closer look at it later tonight.
>> I was wondering one thing: imagine doing a 200x200 -> 400x400 linear 
>> interpolation resizing.
>>
>> The filter gets as input a (for ex.) 4x100 slice. It can then 
>> interpolate the line numbers (1,2,3,4,5,6,7) of the output. For the
>> next slice, it would be able to output the lines
>> (9,10,11,12,13,14,15). But to evaluate the output line 8, it'll need
>> both the input line 4 and 5. So to do slice-based resizing, it would
>> be necessary a complicated, resize algorithm dependent, caching. Also
>> it would require some kind of memcpy.
>>
>> So my opinion is that implementing slices in resizing is hard and
>> maybe not worth the effort. In the other hand, colospace conversion
>> should be pretty simple. Or am I missing something?
>>
> 
> I believe that this caching is already implemented by libswscale.

Does imgresample.c also support this?

-Vitor