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

Yong Dung Vu dvu at csusb.edu
Tue May 15 14:43:36 CEST 2012


Thanks a lot,
Dung Vu


On 05/14/2012 07:18 PM, jiayaowang wrote:
> 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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