[FFmpeg-user] Can I speed up transcoding?
Henk D. Schoneveld
belcampo at zonnet.nl
Tue Jan 8 11:02:04 CET 2013
In your 1st posting, ffmpeg cli output, can be seen that the file is encode with threads=1, that suggests on EC2 only 1 cpu core is presented to ffmpeg. So if more cores are available to you on EC2 you probably have to specifically have to ask for more cores with the threads 2 after c:v. Like ffmpeg -y -i some file.ext -c:v libx264 -threads 2 etc.
On Jan 8, 2013, at 10:02 AM, Henk D. Schoneveld <belcampo at zonnet.nl> wrote:
> On Jan 8, 2013, at 4:56 AM, Leo Papadopoulos <leo at telecomcto.com> wrote:
>> Thanks for replying.
>> I have tried ultrafast but it uses almost 2x the disk space. I may still go
>> with this option. I need to see how much more disk costs on Amazon's EC2. I
>> was hoping maybe there were other ways. I see a 'threads' option in the
>> ffmpeg command, but I don't know if this would help.
> AFAIK and just tested on OSX threads is enabled by default. It takes the cores it finds available. I don't know how EC2 presents it's recourses. You can try -threads 2 or 3 depending what the system else is supposed to do. On a i5 2500k/4-cores I get fps=150 from an arbitrary file to 640x480 output in mp4 container.
>> The reason I use -vsync 1 is because someone suggested this from this
>> mailing list when I was having trouble with lip sync in the video. However,
>> re-encoding the H.264 (I think fixes lip sync). Do you think it would help
>> to either remove or play with -vsync?
>> Leo P.
>> Leo Papadopoulos (leo at telecomcto.com)
>> TelecomCTO, LLC <http://telecomcto.com>
>> Virtual Number: +1(203)539-0448
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