v4l2loopback and v4l2sink do not play nice with ffmpeg.

[umlaeute]

v4l2loopback and v4l2sink do not play nice with ffmpeg.

[umlaeute]

should be fixed now (in experimental)
please report, whether i can close it

btw, whats the "10.04" src?

[quackking]

Built experimental branch on 10.10. Looks good! "Critical error" on launch is no longer there, and rtmp ffmpeg now works! However Cheese now looks ugly - continuing to investigate. For now I would have to say you rule!! Excellent, thank you! THis is a giant step for anybody who wants to link gstreamer to Flash Media Servers via rtmp, which is a big deal!

If we uncover additional bugs we will post.

One question, how can we create more than one /dev/videoX? The documentation is not all that clear. At modprobe time what parameter do we pass?

(sorry I meant to say 'as pulled from 11.04 not 10.04 before, brain freeze)

[umlaeute]

ah "11.04" is a date; brain freeze on my side....

as for videoX: try the "devices" parms:

modprobe v4l2loopback devices=10

should give you /dev/video0 .. /dev/video9

for the ugliness of cheese, pleae open another ticket (when you have more info)

[quackking]

For completeness I should mention that we had to install gstreamer0.10-plugins-good version 0.10.27-1~maverick1 from https://launchpad.net/~gstreamer-developers/+archive/ppa in order to make this work. The debs in Ubuntu 10.10 Maverick do not work correctly, you must install this upstream gstreamer or you will get teh Critical Error on gstreamer launch.

Thank you for the tip re: device= - and we will open a new ticket when we investigate the Cheese ugliness further.

[umlaeute]

thanks for the hints on the required gstreamer version

[quackking]

With the new source compiled and modprobed I now see this:

gst-launch-0.10 [ourvideoSrouce] ! queue ! videoscale ! videorate ! video/x-raw-yuv,width=640,height=360,framerate=30/1,format=(fourcc)UYVY ! v4l2sink device=/dev/video0
Setting pipeline to PAUSED ...
libv4l2: error getting pixformat: Invalid argument
Pipeline is live and does not need PREROLL ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
.
.
.

libv4l2: error getting pixformat: Invalid argument is new.

Although I can open Cheese and see the stream, and ffmpeg seems to work, I am not sure what to do about this error. Changing to xvmiagesink eliminates it of course. Adding ffmpegcolorspace element has no effect.

Any iideas?

[quackking]

More information.

$ sudo insmod v4l2loopback devices=2

Check to see, sure enough /dev/video0 and /dev/video1 are created.

$ gst-launch-0.10 [ourvideoSrouce] ! queue ! videoscale ! videorate ! video/x-raw-yuv,width=640,height=360,framerate=30/1,format=(fourcc)UYVY ! v4l2sink device=/dev/video0

(we get the pixformat error)

(in another terminal window)
$ cheese

Cheese shows video fine.
Stop cheese

cntl-c to kill the gst-launch, then change the output device to /dev/video1, eg,

$ gst-launch-0.10 [ourvideoSrouce] ! queue ! videoscale ! videorate ! video/x-raw-yuv,width=640,height=360,framerate=30/1,format=(fourcc)UYVY ! v4l2sink device=/dev/video1

Repeat cheese tests, all ok. So far we have demonstrated that the driver lets you write to the /dev/video device of your choice.

However, after a variable number of executions of

$ gst--launch-0.10 [ourvideoSrouce] ! queue ! videoscale ! videorate ! video/x-raw-yuv,width=640,height=360,framerate=30/1,format=(fourcc)UYVY ! v4l2sink device=/dev/video0

and killing it with cntl-c, the /dev/video0 device gets 'stuck' - eventually you see a message which indicates that it is not available (I will try to get that for you but for now, let's move on)

At that point you can STILL

$ gst--launch-0.10 [ourvideoSrouce] ! queue ! videoscale ! videorate ! video/x-raw-yuv,width=640,height=360,framerate=30/1,format=(fourcc)UYVY ! v4l2sink device=/dev/video1 (the other device is ok)

Kill that and try to

$ sudo rmmod v4l2loopback

You cant! It is still in use by vdeodev (and v4l2_compat_ioctl32)
You can't even

$ sudo rmmmod -f (any or all of those devices)

Uh oh.