[FFmpeg-trac] #7221(ffmpeg:new): V4l2 fails when attempting a second capture

FFmpeg trac at avcodec.org
Sat May 19 22:23:42 EEST 2018


#7221: V4l2 fails when attempting a second capture
----------------------------------+---------------------------------------
             Reporter:  andrelcm  |                     Type:  defect
               Status:  new       |                 Priority:  normal
            Component:  ffmpeg    |                  Version:  unspecified
             Keywords:            |               Blocked By:
             Blocking:            |  Reproduced by developer:  0
Analyzed by developer:  0         |
----------------------------------+---------------------------------------
 I am trying to capture video using this card: https://www.ebay.com/itm
 /1080P-60FPS-USB-3-0-HD-HDMI-Video-Capture-Card-Box-for-Windows-Mac-
 Linux-/263257786337?hash=item3d4b6307e1

 The kernel driver is uvcvideo. The first capture is ok, everything works
 fine, but the second attempt fails with this information: Dequeued v4l2
 buffer contains corrupted data (0 bytes). Then, only audio is captured.

 Using VLC, I can watch video from it no matter how many times I reopen the
 program.

 I can successfully capture video again if I reload the module with the
 command bellow:
 {{{
 sudo modprobe -v -r uvcvideo && sudo modprobe -v uvcvideo
 }}}
 Or if I reser the card with this:
 {{{
 echo 0 > /sys/bus/usb/devices/4-3/authorized
 echo 1 > /sys/bus/usb/devices/4-3/authorized
 }}}

 Here the output of ffmpeg:
 {{{
 ffmpeg version N-91127-g411f7141a3 Copyright (c) 2000-2018 the FFmpeg
 developers
   built with gcc 7 (Ubuntu 7.3.0-16ubuntu3)
   configuration: --enable-nonfree --disable-shared --enable-nvenc
 --enable-cuda --enable-cuvid --enable-pthreads --extra-
 cflags=-I/usr/local/cuda-9.0/include --extra-
 ldflags=-L/usr/local/cuda-9.0/lib64
   libavutil      56. 18.102 / 56. 18.102
   libavcodec     58. 19.102 / 58. 19.102
   libavformat    58. 15.100 / 58. 15.100
   libavdevice    58.  4.100 / 58.  4.100
   libavfilter     7. 24.100 /  7. 24.100
   libswscale      5.  2.100 /  5.  2.100
   libswresample   3.  2.100 /  3.  2.100
 Guessed Channel Layout for Input Stream #0.0 : stereo
 Input #0, alsa, from 'hw:2,0':
   Duration: N/A, start: 1526757005.217295, bitrate: 1536 kb/s
     Stream #0:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
 [video4linux2,v4l2 @ 0x5646abe4c400] Dequeued v4l2 buffer contains
 corrupted data (0 bytes).
 Input #1, video4linux2,v4l2, from '/dev/video0':
   Duration: N/A, start: 0.000000, bitrate: 995328 kb/s
     Stream #1:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 1920x1080,
 995328 kb/s, 30 fps, 30 tbr, 1000k tbn, 1000k tbc
 Stream mapping:
   Stream #1:0 -> #0:0 (rawvideo (native) -> h264 (h264_nvenc))
   Stream #0:0 -> #0:1 (pcm_s16le (native) -> aac (native))
 Press [q] to stop, [?] for help
 [video4linux2,v4l2 @ 0x5646abe4c400] Dequeued v4l2 buffer contains
 corrupted data (0 bytes).
     Last message repeated 30 times
 Output #0, mpegts, to '/tmp/out.ts':
   Metadata:
     encoder         : Lavf58.15.100
     Stream #0:0: Video: h264 (h264_nvenc) (High 4:4:4 Predictive),
 yuv444p(progressive), 1920x1080 [SAR 1:1 DAR 16:9], q=19-50, 8000 kb/s, 30
 fps, 90k tbn, 30 tbc
     Metadata:
       encoder         : Lavc58.19.102 h264_nvenc
     Side data:
       cpb: bitrate max/min/avg: 12000000/0/8000000 buffer size: 16000000
 vbv_delay: -1
     Stream #0:1: Audio: aac (LC), 48000 Hz, stereo, fltp, 128 kb/s
     Metadata:
       encoder         : Lavc58.19.102 aac
 frame=    3 fps=0.0 q=21.0 size=      10kB time=00:18:06.70 bitrate=
 0.1kbits/
 frame=    3 fps=3.0 q=21.0 size=      19kB time=00:18:06.70 bitrate=
 0.1kbits/
 frame=    3 fps=2.0 q=21.0 size=      28kB time=00:18:06.70 bitrate=
 0.2kbits/
 frame=    3 fps=2.0 q=21.0 Lsize=     182kB time=00:18:06.76 bitrate=
 1.4kbits/s speed= 709x
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/7221>
FFmpeg <https://ffmpeg.org>
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