[FFmpeg-devel] ffmpeg multithread decoding, the rate is not improved

[jiayaowang]

I am not know transcoding, I know decoding,
for MT decoding, there are two methods, slice level parallel and frame level parallel.
frame level is decoding multi-frames at the same time, each frame in one separate thread.
Transcoding maybe use the same flow, I am not sure.
Thanks.


2012-05-15 



jiayaowang 



发件人： Yong Dung Vu 
发送时间： 2012-05-15  02:25:19 
收件人： FFmpeg development discussions and patches 
抄送： 
主题： Re: [FFmpeg-devel] ffmpeg multithread decoding,the rate is not improved 
 
Hello,
I am also curious about transcoding with multithread. The decoding are
distributed to other threads, then encoding on the main thread ? Is that
true ?
Thanks
Dung Vu
On 05/14/2012 02:39 AM, jiayaowang wrote:
> Please make sure that the test.264 has multi-slices in one picture.
>
>
> 2012-05-14 
>
>
>
> jiayaowang 
>
>
>
> 发件人： 艾薇妮 
> 发送时间： 2012-04-28  16:02:49 
> 收件人： ffmpeg-devel 
> 抄送： 
> 主题： [FFmpeg-devel] ffmpeg multithread decoding, the rate is not improved 
>  
> Hi!
>  I'm trying to decode .264 file using ffmpeg with -threads option,i'm  using a dual-core computer and build ffmpeg using the pthread option,but   the rate is not improved,i wonder what is the reason.
>  my command line is:
>  time ./ffmpeg -y -threads 2  -thread_type slice -i test.264 test.yuv
>  and 
>  time ./ffmpeg -y -threads 1 -i test.264 test.yuv 
>  the time is close,i didn't see any improvement.
>  i tried to encode and transcode video using -threads option,i can see  great improvment about twice speed improvent ,why does the multithread  decode is not good?
>  i would be so much appreciated that if you  can answer me this question!
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