[FFmpeg-devel] Some footage for H264 on kdenlive.org

Loren Merritt lorenm
Wed Feb 25 04:52:46 CET 2009

On Tue, 24 Feb 2009, Carl Eugen Hoyos wrote:

> I tested a few random videos (all with B-Frames) today on different hardware,
> and I always saw more than 50% speed improvement (= less than half needed
> processor time) for skiploopfilter=all:skipframe=nonref
> I severely doubt there is any processor where multithreaded h264 decoding will
> make the difference between usable and non-usable, except that the user may then
> use deblocking on B-frames while editing in real-time where he has to live with
> P frames without loop-filter currently.

You doubt there's a processor that gets more than 2x speedup from multithreaded
h264 decoding? On the contrary, if you don't get nearly 4x on a quadcore,
you're doing something wrong. Because h264 decoding does have 4x parallelism
possible, and it does not require duplicating any computations.
Granted, any quadcore is probably also fast enough that it doesn't need
multithreading in order to decode in realtime, is that the question?

--Loren Merritt

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