[Kdenlive-devel] [Mlt-devel] h264 AVCHD and MLT multi-treaded decoding

[Dan Dennedy]

Jean-Michel Pouré wrote:
> Dear Dave and friends,
>
> Thank you for this answer about MLT libavformat multi-threaded decoding.
> I just tested MLT and Kdenlive with Canon HG10 h264 AVCHD files.
>
> Decoding works but is *** very *** slow, even with real_time=1.
> The first core of my Athlon AMD64x2 is floded.
> And the second core stands nearly idle.
>
>   
I have a Core 2 Duo. HDV is playing poorly for me as well. Furthermore, 
neither CPU is being utilized anywhere near its fullest. This means 
there is a "bottle neck" somewhere. I want to look into this first so I 
can be sure to observe any multi-threaded usage of ffmpeg.
> Could someone look at consumer_avformat.c to see 
> if multi-threaded decoding could be enabled.
>
>   
I took a look at ffmpeg to see how to integrate multi-threading, and it 
looks easy.
> Kind regards,
> Jean-Michel
>
> P.S. This is a month old message from Dan:
>
>   
>> When using Kdenlive, the activity of by AMDx2 processor sometimes
>> reaches 50%. Is MLT multi-threaded?
>>     
>
> Yes, but only in a trivial sense because there is no parallel
> processing. It just uses the threading for latency between the consumer
> and all the processing ahead of it. For example, while one thread in the
> the SDL consumer is updating the display, another thread is preparing
> the next or additional frames in a serial fashion. This is what the
> generic consumer property "real_time" controls. When set to 1, there is
> a queue that can fill causing it to skip processing frame to maintain
> "realtime." When set to 0, the framework consumer multithreading is
> disabled.
>
>   
>> Can it take advantage of ffmpeg AVCHD multi-threaded decoding?
>>     
> Maybe just by setting some options in consumer_avformat.c.
>
>
>