[FFmpeg-user] Correct way to get preview stream with no encoding?

Dennis mediastream at gmail.com
Fri Oct 11 21:08:43 CEST 2013


I'd go with VLC live encoder and playback, vlc forum is a good place to
start.
UDP would be least overhead.


On Fri, Oct 11, 2013 at 1:37 PM, Jason Runta <jrunta at gmail.com> wrote:

> Not sure if this is the best way, but here's what I ended up doing:
>
> ffmpeg -y -f dshow -threads 3 -s 640x480 -i video="Microsoft LifeCam
> Cinema":audio="Desktop Microphone (Cinema - Mi" -c:v copy -an -f rawvideo
> udp://localhost:1234 -f flv -c:v libx264 -tune zerolatency -preset
> ultrafast -b:v 400k -pix_fmt yuv420p -c:a libmp3lame -q:a 2 -b:a 56k
> -maxrate 750k "myMovie.flv"
>
> and then viewing my video from ffplay:
> ffplay -s 640x480 -pix_fmt yuyv422 -f rawvideo -i udp://localhost:1234
>
> I'm processing everything off one ffmpeg call here instead of doing
> subsequent calls to ffmpeg, and specifying to use up to 3 threads to
> accomplish the raw video output (no audio) and then also encoding and
> saving the file out.
>
> Is there a better way? How about getting my stream to ffplay, is streaming
> point-to-point over UDP the best option?
>
>
> On Fri, Oct 11, 2013 at 10:15 AM, Dennis <mediastream at gmail.com> wrote:
>
> > I think you do both in one shot.
> > ffmpeg -i v4l -c:v libx264 -s 640x480 OUTPUT -c copy PREVIEW
> >
> >
> > On Wed, Oct 9, 2013 at 5:35 PM, Jason Runta <jrunta at gmail.com> wrote:
> >
> > > I'm trying to make a program that behaves similar to FMLE where I need
> to
> > > display a preview of the video from my webcam as well as a preview of
> the
> > > encoded output.
> > >
> > > I was wondering if anyone could suggest the proper way of getting a
> > preview
> > > stream without any encoding being done to it.
> > >
> > > Do I need to make one ffmpeg call that uses -vcodec copy -acodec copy
> and
> > > then redirect  the output from that into subsequent ffmpeg calls?
> > >
> > > If anyone has a good idea of how to get the preview stream into a C#
> app
> > > I'm all ears as well =) I'm pretty sure FMLE basically runs on top of
> > > ffmpeg so if they're doing it, I should be able to do it...
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