[Bug 725374] New: Uvch264src fails with multiple cameras

[GStreamer (bugzilla.gnome.org)]

https://bugzilla.gnome.org/show_bug.cgi?id=725374
  GStreamer | gst-plugins-bad | 1.2.3

           Summary: Uvch264src fails with multiple cameras
    Classification: Platform
           Product: GStreamer
           Version: 1.2.3
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: major
          Priority: Normal
         Component: gst-plugins-bad
        AssignedTo: gstreamer-bugs at lists.freedesktop.org
        ReportedBy: mark at markscudder.com
         QAContact: gstreamer-bugs at lists.freedesktop.org
     GNOME version: ---


I have GStreamer 1.2.3 built and working on a Linux Mint 16 system following
Alex Csete's instructions on his wiki (so it's built in my home directory,
~/gst/runtime).

I have three Logitech c920s I would like to record from, and since the camera
has a built-in h.264 encoder, my Linux box has enough power to record multiple
cameras at once, because it's not doing three realtime h.264 encodes on the
CPU, just writing 3mbit/sec streams to disk. I did some experimenting with
v4l2src, and verified I could access and write the h.264 stream from all three
c920s at once. But some issues with v4l2src led me to want to try uvch264src
instead.

Following the examples on Alex's blog, I open a terminal window, run the
set_env.sh script, and issue the following command (based on his example but
using a filesink instead of videosink, to save the video):

~/gst/runtime/bin/gst-launch-1.0 -v -e uvch264src device=/dev/video0 name=src
auto-start=true src.vfsrc ! queue !
video/x-raw,format=\(string\)YUY2,width=320,height=240,framerate=10/1 !
xvimagesink sync=false src.vidsrc ! queue !
video/x-h264,width=1280,height=720,framerate=30/1 ! filesink
location=/home/mark/test1.mp4

This works. A small preview window is displayed on the screen, and the h.264
stream is recorded to test1.mp4, though it has to be run through ffmpeg -i
test1.mp4 -vocdec copy fixed.mp4 before it's usable in non-GStreamer-based
players. (I don't mind that, if there's no way to properly mux it into a
compatible mp4 file in the pipeline.)

I then open another terminal window, run the set_env.sh script, and change the
command to connect to the next camera, and write a different file:

~/gst/runtime/bin/gst-launch-1.0 -v -e uvch264src device=/dev/video1 name=src
auto-start=true src.vfsrc ! queue !
video/x-raw,format=\(string\)YUY2,width=320,height=240,framerate=10/1 !
xvimagesink sync=false src.vidsrc ! queue !
video/x-h264,width=1280,height=720,framerate=30/1 ! filesink
location=/home/mark/test2.mp4

And it doesn't work. GStreamer displays the following in the terminal window:

Setting pipeline to PAUSED ...
/GstPipeline:pipeline0/GstUvcH264Src:src/GstV4l2Src:v4l2src0: num-buffers = -1
/GstPipeline:pipeline0/GstUvcH264Src:src/GstV4l2Src:v4l2src0: device =
/dev/video1
/GstPipeline:pipeline0/GstUvcH264Src:src/GstV4l2Src:v4l2src0: num-buffers = -1
/GstPipeline:pipeline0/GstUvcH264Src:src/GstV4l2Src:v4l2src0: device =
/dev/video1
/GstPipeline:pipeline0/GstUvcH264Src:src/GstCapsFilter:capsfilter2: caps =
video/x-raw, format=(string)YUY2, width=(int)320, height=(int)240,
framerate=(fraction)10/1
/GstPipeline:pipeline0/GstUvcH264Src:src: ready-for-capture = false
/GstPipeline:pipeline0/GstUvcH264Src:src/GstV4l2Src:v4l2src0: num-buffers = -1
/GstPipeline:pipeline0/GstUvcH264Src:src/GstV4l2Src:v4l2src0: device =
/dev/video1
/GstPipeline:pipeline0/GstUvcH264Src:src/GstCapsFilter:capsfilter3: caps =
video/x-h264, width=(int)1280, height=(int)720, framerate=(fraction)30/1
/GstPipeline:pipeline0/GstUvcH264Src:src/GstCapsFilter:capsfilter4: caps =
video/x-raw, format=(string)YUY2, width=(int)320, height=(int)240,
framerate=(fraction)10/1
/GstPipeline:pipeline0/GstUvcH264Src:src/GstUvcH264MjpgDemux:uvch264mjpgdemux0:
num-clock-samples = 0
/GstPipeline:pipeline0/GstUvcH264Src:src/GstUvcH264MjpgDemux:uvch264mjpgdemux0:
device-fd = 12
/GstPipeline:pipeline0/GstUvcH264Src:src/GstCapsFilter:capsfilter5: caps =
image/jpeg, width=(int)320, height=(int)240, framerate=(fraction)30/1
Pipeline is live and does not need PREROLL ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
/GstPipeline:pipeline0/GstUvcH264Src:src/GstV4l2Src:v4l2src0.GstPad:src: caps =
image/jpeg, width=(int)320, height=(int)240, pixel-aspect-ratio=(fraction)1/1,
framerate=(fraction)30/1
/GstPipeline:pipeline0/GstUvcH264Src:src/GstCapsFilter:capsfilter5.GstPad:src:
caps = image/jpeg, width=(int)320, height=(int)240,
pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1
/GstPipeline:pipeline0/GstUvcH264Src:src/GstUvcH264MjpgDemux:uvch264mjpgdemux0.GstPad:jpeg:
caps = image/jpeg, width=(int)320, height=(int)240,
pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1
/GstPipeline:pipeline0/GstUvcH264Src:src/GstUvcH264MjpgDemux:uvch264mjpgdemux0.GstPad:sink:
caps = image/jpeg, width=(int)320, height=(int)240,
pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1
/GstPipeline:pipeline0/GstUvcH264Src:src/GstCapsFilter:capsfilter5.GstPad:sink:
caps = image/jpeg, width=(int)320, height=(int)240,
pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1
ERROR: from element
/GstPipeline:pipeline0/GstUvcH264Src:src/GstV4l2Src:v4l2src0: Internal data
flow error.
Additional debug info:
gstbasesrc.c(2865): gst_base_src_loop ():
/GstPipeline:pipeline0/GstUvcH264Src:src/GstV4l2Src:v4l2src0:
streaming task paused, reason not-negotiated (-4)
EOS on shutdown enabled -- waiting for EOS after Error
Waiting for EOS…

And does nothing until I Ctrl-C it.

If the first pipeline is not running, this pipeline runs just fine, but they
won't run in parallel. I don't feel that GStreamer is being clear about
what/where the problem is, but I understand since it's in development I have to
dig and experiment.  I also don't see a reason it wouldn't work, since Linux
seems to enumerate the cameras as separate entities, and any binary should be
able to run multiple times on the same box if it's opening different devices. I
just don't know where to start. Can someone help me get these working in
parallel? Like I said, even though c920 support isn't perfect in v4l2src, I was
able to record three cameras in parallel.

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