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• i am using ffmpeg library API to record camera stream in to mp file, working with one camera but throwing an error if more than one camera connected

  11 avril 2018, par RAngadi

  using ffmpeg API to record AV stream in to mp4 file for multiple cameras using multiple threads, but it is working with single camera connected, but if we connect more than 2 camera and try to record AV stream of both the camera streams in respected mp4 files seperately it is throwing an error ("Error Muxing Packet") ;
  could you please provide and solution or answer for this..

• How to record video from old webcam using ffmpeg on Linux ?

  5 février 2015, par Moomin

  After couple of hours I finally accepted my absolute lack of knowledge and decided to post this question here.
  I’m trying to record video from an old external USB webcam (Media-Tech MT400 -> 0c45:6029) with ffmpeg but without much success.

  First thing I’ve tried was to run to try something that works for the built-in webcam) :

  ffmpeg -f v4l2 -i /dev/video1 test.avi

  But that returned a following error :

  Cannot find a proper format for codec 'none' (id 0), pixel format 'none' (id -1)

  Here is what I get from v4l2-ctl -d /dev/video1/ --all --list-formats-ext

  Driver Info (not using libv4l2):
  
          Driver name   : sonixb
  
          Card type     : USB camera
  
          Bus info      : usb-0000:04:00.0-1
  
          Driver version: 3.10.17
  
          Capabilities  : 0x85000001
  
                  Video Capture
  
                  Read/Write
  
                  Streaming
  
                  Device Capabilities
  
          Device Caps   : 0x05000001
  
                  Video Capture
  
                  Read/Write
  
                  Streaming
  
  Priority: 2
  
  Video input : 0 (sonixb: ok)
  
  Format Video Capture:
  
          Width/Height  : 352/288
  
          Pixel Format  : 'S910'
  
          Field         : None
  
          Bytes per Line: 352
  
          Size Image    : 126720
  
          Colorspace    : SRGB
  
  Streaming Parameters Video Capture:
  
          Frames per second: invalid (0/0)
  
          Read buffers     : 2
  
  
  
  
  
  
  
  ioctl: VIDIOC_ENUM_FMT
  
      Index       : 0
  
      Type        : Video Capture
  
      Pixel Format: 'S910'
  
      Name        : S910
  
              Size: Discrete 160x120
  
              Size: Discrete 176x144
  
              Size: Discrete 320x240
  
              Size: Discrete 352x288
  
  
  
      Index       : 1
  
      Type        : Video Capture
  
      Pixel Format: 'BA81'
  
      Name        : BA81
  
              Size: Discrete 160x120
  
              Size: Discrete 176x144

  Unfortunately that was not of much help to me, but I tried capturing webcam output with VLC and recording it which.... WORKED !

  I tried ffmpeg -i vlc-record[...].avi on VLC recording which returned following information :

  Input #0, avi, from 'vlc-record-2015-02-05-05h22m52s-v4l2____dev_video1-.avi':
  
    Duration: 00:00:01.58, start: 0.000000, bitrate: 26937 kb/s
  
      Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 352x288, 27671 kb/s, 22.10 tbr, 22.10 tbn, 22.10 tbc

  I thought that was enough information (rawvideo and yuv420p) led to run ffmpeg with following arguments (I have found yuv4 using ffmpeg -formats)

  ffmpeg -f rawvideo -vcodec yuv4 -i /dev/video1 test.avi

  The result was only slightly better than one that I saw after my first attempt :

  [IMGUTILS @ 0x7fff497d3920] Picture size 0x0 is invalid
  
  [rawvideo @ 0x9c4720] Could not find codec parameters for stream 0 (Video: yuv4, yuv420p, -4 kb/s): unspecified size
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  /dev/video1: could not find codec parameters

  Again after some searching and several tries I added ’-video_size cif` option and.... it WORKED !!!!

  Well, not really...

  Input #0, rawvideo, from '/dev/video1':
  
    Duration: N/A, start: 0.000000, bitrate: 30412 kb/s
  
      Stream #0:0: Video: yuv4, yuv420p, 352x288, 30412 kb/s, 25 tbr, 25 tbn, 25 tbc
  
  Output #0, avi, to 'test.avi':
  
    Metadata:
  
      ISFT            : Lavf55.19.104
  
      Stream #0:0: Video: mpeg4 (FMP4 / 0x34504D46), yuv420p, 352x288, q=2-31, 200 kb/s, 25 tbn, 25 tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (yuv4 -> mpeg4)
  
  Press [q] to stop, [?] for help
  
  frame=   13 fps=6.3 q=24.8 Lsize=    1064kB time=00:00:00.52 bitrate=16759.3kbits/s    
  
  video:1058kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.554114%

  LED on webcam turned on as during capturing video with VLC but all that was recorded was TV-like noise.

  So here I am after 7 hours - still without work solution - asking for your help.

  Thanks in advance.

• Can I use FFMPEG to record ultra sonic ?

  23 février 2018, par OtakuFitness

  I use av_dump_format() to check information and I get

  Stream #0:0: Audio: pcm_s16le, 48000Hz, 2 channels, s16, 1536kb/s

  Now I can record music, it’s working well(I generated a pcm file to listen). However, in terms of ultra sonic, I can’t record any useful audio information, so can I use FFmpeg to record ultra sonic ?