[FFmpeg-user] ffmpeg multi threading
shacky83 at gmail.com
Wed Apr 27 09:39:58 CEST 2011
I solved the problem on the x264 preset.
I made a benchmark between the x264 with -threads 0 option and the flv
codec with the command I specified in my first message, but the flv
codec is faster than the x264 one.
How is it possible?
2011/4/27 shacky <shacky83 at gmail.com>:
> Thank you very much for your answer.
> I've never used the libx264 codec, so I'm looking to its options.
> I tried your command but I got the "Unrecognized option 'preset'" error.
> I tried to remove the -presets parameter but I got this error:
> Stream mapping:
> Stream #0.0 -> #0.0
> Stream #0.1 -> #0.1
> Error while opening encoder for output stream #0.0 - maybe incorrect parameters
> such as bit_rate, rate, width or height
> Could you help me please?
> 2011/4/26 Lou <lou at fakeoutdoorsman.com>:
>> On Tue, 26 Apr 2011 16:52:27 +0200
>> shacky <shacky83 at gmail.com> wrote:
>>> I'm using ffmpeg on my Windows machine to convert some videos from TS
>>> to FLV. I have a quadcore processor and I'm making some benchmark to
>>> have the conversion process as fast as possible.
>>> I'm using the binary win32 static version of ffmpeg from
>> Newer Windows builds are located here:
>>> The command I use to convert from TS to FLV is the following:
>>> C:\Record\tv>c:\utils\ffmpeg-r26400\bin\ffmpeg.exe -i myfile.ts -y -f
>>> flv -s 320x240 -b 464k -ac 2 -ar 22050 -ab 48k myfile.flv
>>> But if I try to add the -threads 2 or -threads 4 parameter I get this
>>> Error while opening encoder for output stream #0.0 - maybe incorrect
>>> parameters such as bit_rate, rate, width or height
>>> so I'm thinking that ffmpeg is not using all available cores of my
>>> Could you help me please?
>>> Thank you very much!
>> flv (the encoder, not the container) does not support multithreaded
>> Use libx264 if you want to output to flv and have multithreaded
>> encoding. Example:
>> ffmpeg -i input -vcodec libx264 -preset medium -crf 24 -threads 0 \
>> -vf scale=320:-1 -acodec libmp3lame -ar 44100 -aq 5 output.flv
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>> ffmpeg-user at ffmpeg.org
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