[Libva] Intel H264 decoding performance

[Christophe Oosterlynck]

Hi,

On the Intel Linux Graphics site, a summary of supported features is given (
http://intellinuxgraphics.org/vaapi.html). For H264, High profile is
supported "up to 40 Mbps". This 40Mbps, is this independent of the
complexity of the clip?

I have 3 H264 test clips at different bitrates. Using software decoding,
the different clips at the same bitrate will behave differently: some clips
decode fine @ 20mbps while others have severe frame drops @ 20mbps => the
complexity of the clip information is probably an issue here.
I don't see this behavior with my test clips when using VAAPI. All clips,
even the most complex ones, play fine even @ 40mbps. This is great, but I
wonder if bitrate is indeed the only factor that influences the video
decoding performance on Intel? So can I assume that any clip @ 40mbps will
play fine?

And what about playing multiple clips at the same time. I can play 2 40mbit
h264 clips fine, but 3 clips sometimes gives severe framedrops depending on
the clips I'm using. How should I interpret the 40 mbps limit mentioned on
the Intel page now? I can play multiple clips fine as long as the total
bitrate is <= 40 mbit? But 2 clips at 40 mbps seem to play fine here...

Btw, I'm using an Intel Huron River platform.

Best regards,

Christophe
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