[vlc-devel] [PATCH 2/2] avcodec: va: wait indefinitely until a surface is available
robux4 at ycbcr.xyz
Thu Jul 9 17:24:25 CEST 2020
On 2020-07-09 16:31, Rémi Denis-Courmont wrote:
> Le jeudi 9 juillet 2020, 12:56:30 EEST Steve Lhomme a écrit :
>> If there's no surface available the decoder should wait for one to be
>> available, not get an error and not try to decode anymore. When pictures
>> (and thus surfaces) were coming from the display a picture_pool_Wait() was
>> used, so in the normal case we should do something similar.
> In theory, yes. In practice, unfortunately, dubious.
>> The infinite looping shouldn't be an issue as on Flush or Close the decoder
>> will release all the past pictures/surfaces. So there will be new surfaces
>> available for past calls.
> It will still deadlock if one of the following is true:
> - the loop is running on the main decoder thread, and thus will block flushing/
> closing, or
I just tried with --avcodec-threads=1 and it works fine. The calls are
done in the DecodeBlock() thread. Seeking works, even while paused.
> - the picture pool is too small even for the "few" allocations after flush, in
> particular if there is shortage of memory on the GPU.
If you mean the picture pool and not the surface pool, ie the dummy
pictures where surfaces are attached, I don't think the size matters.
The surfaces will be flushed eventually and thus the pictures they are
attached to. If one works, the other one works too.
> Not sure it's really safe yet.
I can't guarantee 100% either, but looking at our code, the lavc codec,
the MPV code and doing the worst tests I can think of, I think it's correct.
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