[FFmpeg-devel] Once again: Multithreaded H.264 decoding withffmpeg?

Måns Rullgård mans
Fri May 30 09:43:35 CEST 2008

Goga777 <goga777 at bk.ru> writes:

>> > Could it be realisitic to achieve lets say a speedup between 30% and 50%
>> > on a modern dual core CPU or are there limitations that make this a
>> > dream? What about using NVIDIA's CUDA or AMD's stream computing to make
>> > use of modern GPUs (given that the "native" acceleration APIs are not
>> > available under Linux)?
> yes, VAAPI under Linux doesn't finish yet. Nobody knows when VAAPI
> will finish http://www.freedesktop.org/wiki/Software/vaapi
>> There is definitively room for 50% decode speed improvement in
>> ffmpeg's h264 decoder but it would take some work. CUDA et al have
>> been discussed in the past (again see archives) but the kist of it is
>> that while very fast, the latency can be quite significant so you
>> would have to do some fancy coding to hide that. The h264 acceleration
>> 'featured' by most modern GPUs is actually a HW decoder and they are
>> generally limited to Level 4.1 decode 
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> what's mean ? with the HW decoding the pictures quality will not the best ?

It means that they are unable to decode streams using certain

M?ns Rullg?rd
mans at mansr.com

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