[FFmpeg-user] ffmpeg extremely high consumption

[Frans Gouverne]

You need to specify option -re before the input file to read input as
native frame rate. Otherwise ffmpeg will try to convert as fast as possible
(neglecting the input frame rate), using as much as CPU power as it can
get. As a result, you cannot view the output stream as well. So please use
something like:

ffmpeg -re -i video.mp4 [...]

I have a test system with much less CPU resources as your system but my CPU
power is not exceeding around 60%. But when I do not use option -re it goes
up to 175%!



2015-06-14 18:16 GMT+02:00 En Figureo Canal <figureo56.com at gmail.com>:

> On Sat, Jun 13, 2015 at 10:28 PM, Pavel Koshevoy <pkoshevoy at gmail.com>
> wrote:
>
> > On 6/13/15 17:49, En Figureo Canal wrote:
> >
> >> On Sat, Jun 13, 2015 at 8:24 PM, Moritz Barsnick <barsnick at gmx.net>
> >> wrote:
> >>
> >>  On Sat, Jun 13, 2015 at 19:17:51 -0400, En Figureo Canal wrote:
> >>>
> >>>> Noticed that, after Henk's reply, if I use -vcodec copy then the
> output
> >>>> will "copy" the source video's attribute (-vb, size, etc...), but, if
> I
> >>>> really need to set the video rate (-vb) then I need to specify the
> codec
> >>>> needed to encode the new video.
> >>>>
> >>> No, it does not copy the attributes (those are very had to duplicate),
> >>> it copies the stream without reencoding. You wouldn't even need libx264
> >>> for that.
> >>>
> >>>   <http://ffmpeg.org/mailman/listinfo/ffmpeg-user>
> >>>
> >>>  I understand I don't need libx264 but, when I tried it like this:
> >>
> >> ffmpeg -i video.mp4 -vcodec copy -vb 1024k -f flv rtmp://ip/live/test
> >>
> >> the output rate was the original video rate at 4M
> >>
> >> But, if I do this:
> >>
> >> ffmpeg -i video.mp4 -vcodec libx264 -vb 1024k  -f flv
> rtmp://ip/live/test
> >>
> >> the output rate is at 1M but video freezes.
> >>
> >
> > You either need a faster computer, or a hardware accelerated encoder
> > (nvenc if you have compatible NVIDIA card), or you can use a less
> demanding
> > libx264 preset -- "veryfast" might work, "ultrafast" is most likely to
> > work.  I believe the default is "medium".  The cheapest and quickest
> thing
> > you can try is adding -preset ultrafast after libx264.  If you don't like
> > the quality try -preset veryfast. If that fails consider using nvenc.
> >
> > Also, see here -- https://trac.ffmpeg.org/wiki/EncodingForStreamingSites
> > -- it appears to be relevant to what you are trying to do.
> >
> >     Pavel.
> >
> >
> > _______________________________________________
> > ffmpeg-user mailing list
> > ffmpeg-user at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-user
> >
>
>
> Pavel thanks for replying.
>
> I'm using ultrafast preset.
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>



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