Adam, I have a strong feeling that the "videorate" there is useless if you don't force a framerate downstream. This is why I put the capsfilter *after* the videorate. You can check this page<http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-base-plugins/html/gst-plugins-base-plugins-videorate.html>, which seems to confirm my theory.
Also, we had a real big problem with the frames dropped, and we only solved it when we forced a certain rate after the videorate element. I believe that if you try to force a certain frame rate directly after the v4l2src, which is not supported by the webcam, that framerate is ignored, so the videorate afterwards, with not additional caps filter afterwards, does nothing but keep the rate the webcam can provide, instead of correcting it to the expected value. Does this make sense? If I'm correct, and we still want to force a frame size *with the jpeg images* rather than the decoded stream, we can maybe add two caps filters: one before the jpegdec (image/jpeg; width=...; height=...) and other after the videorate (video/x-raw-yuv; framerate=30/1), to set the correct rate. What do you think? Best regards Rubén 2011/10/31 McKenzie, Adam <[email protected]> > Hi Edmore, > > If you would like to test it out from the command line you can use: > gst-launch -e v4l2src device=/dev/video0 ! image/jpeg, width=1920, > height=1080, framerate=30/1 ! queue ! jpegdec ! videorate ! > ffmpegcolorspace ! ffenc_mpeg2video ! mpegpsmux ! filesink > location=video.mpg > > This will keep running until you hit a ctrl+c to stop it. The -e is to > make sure that it closes the file correctly so that you end up with good > media. > > I've changed Ruben's "video/x-raw-yuv" to a "image/jpeg". I'm afraid > those c910 cannot do 1080p in raw format, only in motion jpeg. > > If you want to find out exactly what frame rates your webcam can support > at what resolutions the best way is to run: > export GST_DEBUG=3 > Then run: > gst-launch -vvvve v4l2src device=/dev/video0 ! fakesink > > This will spit out a giant list of all the possible settings for that > device that will look something like this: > http://pastebin.com/52NeNkvy > > With each possibility ending with a ";" > > So for example my webcam has this possible caps: > video/x-raw-yuv, format=(fourcc)YUY2, width=(int)1280, height=(int)800, > framerate=(fraction){ 10/1 }; > > So if I use the resolution 1280x800 I can only use a framerate of 10/1 > (aka 10 fps). The next one shows: > > video/x-raw-yuv, format=(fourcc)YUY2, width=(int)1280, height=(int)720, > framerate=(fraction){ 10/1, 15/2 }; > > That if I use 1280x720 I can either use 10/1 or 15/2 (10 FPS or 7.5 FPS) > as options. > > Hope this helps! > Adam > > Adam McKenzie > ITS, University of Saskatchewan > Rm 61 Physics, 116 Science Place > Saskatoon SK S7N 5E2 Canada > (306) 966-2453 > ------------------------------ > *From:* [email protected] [ > [email protected]] on behalf of Edmore Moyo [ > [email protected]] > *Sent:* Monday, October 31, 2011 6:53 AM > *To:* [email protected] > *Subject:* Re: [Matterhorn-users] duration issue? problem with > audio/video sync > > Hello, > > Thank you Rubén Pérez we will give it a try and let you know how it goes. > > Regards, > > Edmore Moyo > > UCT > > >>> Edmore Moyo 10/24/2011 9:24 AM >>> > > Good day, > > > I am a newbie to the Matterhorn community. We are experiencing a similar > issue as the one stated here : * > http://opencast.3480289.n2.nabble.com/Matterhorn-users-duration-issue-problem-with-audio-video-sync-tt6355528.html > * > > *Was this issue ever resolved?* We have tried encoding our presenter file > with *ffmpeg* 0.6, 0.7.6 and 0.8.2 but the duration of the presenter file > is always significantly less than before encoding. This is not the case > with the other files though their duration remains the same. > > This has led us to suspect that this is an issue to do with the source > file generated or some sort of camera incompatibility. We are using a > logitech c910 camera and the following config settings: > > > > capture.device.Presenter.customProducer=v4l2src device=/dev/video0 ! > image/jpeg,width=1920,height=1080,framerate=30/1,rate=30 ! queue ! jpegdec ! > queue ! ffmpegcolorspace > > > > > capture.device.Presenter.flavor=presenter/source > > capture.device.Presenter.outputfile=Presenter.mpg > > capture.device.Presenter.src=/dev/video0 > > capture.device.Presenter.type=CUSTOM_VIDEO_SRC > > > > We were initially using : > > > capture.device.Presenter.customProducer=v4l2src device=/dev/video0 ! > image/jpeg,width=1920,height=1080,*framerate=15/1,rate=15* ! queue ! jpegdec > ! queue ! ffmpegcolorspace > > > but on viewing the source file using *mediainfo *it was not showing a > duration and the frames per second were 0.00fps > > > Regards, > > > Edmore Moyo > > UCT > > > > > ### > > UNIVERSITY OF CAPE TOWN > > This e-mail is subject to the UCT ICT policies and e-mail disclaimer > published on our website at > http://www.uct.ac.za/about/policies/emaildisclaimer/ or obtainable from > +27 21 650 9111. This e-mail is intended only for the person(s) to whom it > is addressed. If the e-mail has reached you in error, please notify the > author. If you are not the intended recipient of the e-mail you may not > use, disclose, copy, redirect or print the content. If this e-mail is not > related to the business of UCT it is sent by the sender in the sender's > individual capacity. > > ### > > _______________________________________________ > Matterhorn-users mailing list > [email protected] > http://lists.opencastproject.org/mailman/listinfo/matterhorn-users > >
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