High CPU usage decoding 4K 60fps video

[Nicolas Dufresne]

Le mardi 26 juillet 2022 à 09:36 +0200, Sergio González via gstreamer-devel a
écrit :
> Dear All,
> 
> I am having an issue when using gstreamer to decode 4K 60fps video in a custom
> app.
> 
> The pipeline's structure is as follows:
> 
> appsrc ! queue ! typefind ! h265parse ! capsfilter ! avdec_h265 ! queue !
> videoconvert ! queue ! appsink
> 
> What I am observing is that when I push buffers to the appsrc, if the decoding
> components are linked, there is a high surge of CPU consumption (as in, 12 of
> the 16 cores are at 100%). However, if on the same machine I just execute the
> same pipeline with gst-launch, the cpu usage is way more reasonable and the
> decoding goes smoothly.

Have you consider running this through a profiler ? (like perf or sysprof on
Linux). This would give you the high spot, and perhaps hint on the problem.

> 
> Adding a Probe to the sink and the source pads of the avdec_h265 tells me that
> the time between decoding buffers at the beginning is of about 200ms, but as
> app keeps decoding, it soon reaches 600ms.
> 
> Do you have some insight on what might cause this? Maybe I am missing some
> property in some of the components?
> 
> Any help would be much appreciated. Let me know if you need any more
> information.
> 
> Cheers,
> Sergio
>