[FFmpeg-devel] [PATCH] libavfilter-soc: Make overlay handle still images

Vitor Sessak vitor1001
Tue May 12 18:43:37 CEST 2009

Vitor Sessak wrote:
> Martin Storsj? wrote:
>> On Fri, 8 May 2009, Vitor Sessak wrote:
>>>> Actually, there's a use for them. Imagine that there's a frame 
>>>> available in
>>>> input 0, but none at all in input 1. 
>>> Is there any way the if (!over->pics[0][0] || !over->pics[1][0]) can be
>>> triggered other than in the first time request_frame() is called? If no,
>>> "!over->pics[1][0]" and "!over->pics[0][0]" are always true.
>>> Note that if one of the inputs each EOF, it will stay at EOF. Note 
>>> also that the poll_frame mechanism guarantees that there is either an 
>>> available frame or EOF for each input.
>> I guess that's true in principle, but what if request_frame() still is 
>> called (for some unknown reason, haven't checked through the rest of 
>> the framework to see if there's something stopping this from 
>> happening) after the first call which returned EOF?
> Indeed, and indeed there is at least one filter that call 
> request_frame() repeatedly even after EOF: overlay. I am not sure if the 
> API should forbid calling request_frame() after EOF or not (comments 
> welcome). Another possibility would be to make avfilter_request_frame() 
> handle that by not calling filter->request_frame() anymore after the 
> first time it returns EOF. Anyway, this discussion goes beyond your 
> patch and I will apply it in a couple of days if nobody else comments on 
> it.

Thanks for the patch, applied.


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