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• Getting ffserver && ffmpeg to work of Debian with Logitech C270 [closed]

  14 mars 2013, par Joseph Baldwin Roberts

  I'm having real trouble getting my webcam to work and I wonder if anyone can help. Im running Raspian on a raspberry pi.

  When I run lsusb I get :

  pi@raspberrycar ~ $ lsusb
  
  Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp.
  
  Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
  
  Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
  
  Bus 001 Device 004: ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB
  
  Bus 001 Device 005: ID 0bda:8176 Realtek Semiconductor Corp. RTL8188CUS 802.11n WLAN Adapter
  
  Bus 001 Device 006: ID 046d:0825 Logitech, Inc. Webcam C270

  When I run v412-ctl —all I get :

  pi@raspberrycar ~ $ v4l2-ctl --all
  
  Driver Info (not using libv4l2):
  
          Driver name   : uvcvideo
  
          Card type     : UVC Camera (046d:0825)
  
          Bus info      : usb-bcm2708_usb-1.2.4
  
          Driver version: 3.6.11
  
          Capabilities  : 0x04000001
  
                  Video Capture
  
                  Streaming
  
  Format Video Capture:
  
          Width/Height  : 640/480
  
          Pixel Format  : 'YUYV'
  
          Field         : None
  
          Bytes per Line: 1280
  
          Size Image    : 614400
  
          Colorspace    : SRGB
  
  Crop Capability Video Capture:
  
          Bounds      : Left 0, Top 0, Width 640, Height 480
  
          Default     : Left 0, Top 0, Width 640, Height 480
  
          Pixel Aspect: 1/1
  
  Video input : 0 (Camera 1: ok)
  
  Streaming Parameters Video Capture:
  
          Capabilities     : timeperframe
  
          Frames per second: 5.000 (5/1)
  
          Read buffers     : 0

  When I run v412-ctl —list-formats I get :

  pi@raspberrycar ~ $ v4l2-ctl --list-formats
  
  ioctl: VIDIOC_ENUM_FMT
  
          Index       : 0
  
          Type        : Video Capture
  
          Pixel Format: 'YUYV'
  
          Name        : YUV 4:2:2 (YUYV)
  
  
  
          Index       : 1
  
          Type        : Video Capture
  
          Pixel Format: 'MJPG' (compressed)
  
          Name        : MJPEG

  My ffserver settings file is /etc/ffserver.conf

  Port 80
  
  BindAddress 0.0.0.0
  
  MaxClients 10
  
  MaxBandwidth 50000
  
  NoDaemon
  
  
  
  <feed>
  
  file /tmp/webcam.ffm
  
  FileMaxSize 10M
  
  </feed>
  
  
  
  <stream>
  
  Feed webcam.ffm
  
  Format mpeg
  
  VideoSize 640x480
  
  VideoFrameRate 10
  
  VideoBitRate 2000
  
  VideoQMin 1
  
  VideoQMax 10
  
  </stream>
  
  
  
  <stream>
  
  Format status
  
  
  
  ACL allow 192.168.2.0 192.168.2.255
  
  </stream>

  My ffmpeg run string is /usr/sbin/webcam.sh

  ffserver -f /etc/ffserver.conf & ffmpeg -v verbose -r 5 -s 640x480 -f video4linux2 -i /dev/video0 http://localhost/webcam.ffm

  When I run this is the output :

  pi@raspberrycar ~ $ sudo /usr/sbin/webcam.sh
  
  ffmpeg version 1.0.5ffserver version 1.0.5 Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Mar 14 2013 18:37:40 with gcc 4.6 (Debian 4.6.3-14+rpi1)
  
   Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Mar 14 2013 18:37:40 with gcc 4.6 (Debian 4.6.3-14+rpi1)
  
    configuration:
  
    libavutil      51. 73.101 / 51. 73.101
  
    configuration:
  
    libavutil      51. 73.101 / 51. 73.101
  
    libavcodec     54. 59.100 / 54. 59.100
  
    libavformat    54. 29.104 / 54. 29.104
  
    libavdevice    54.  2.101 / 54.  2.101
  
    libavfilter     3. 17.100 /  3. 17.100
  
    libswscale      2.  1.101 /  2.  1.101
  
    libavcodec     54. 59.100 / 54. 59.100
  
    libavformat    54. 29.104 / 54. 29.104
  
    libavdevice    54.  2.101 / 54.  2.101
  
    libavfilter     3. 17.100 /  3. 17.100
  
    libswscale      2.  1.101 /  2.  1.101
  
    libswresample   0. 15.100 /  0. 15.100
  
    libswresample   0. 15.100 /  0. 15.100
  
  [video4linux2,v4l2 @ 0xfa5620] [3]Capabilities: 4000001

  I can see the stream on the status page and my webcam light is on but it never loads. Does anyone know what I am doing wrong ?

  Thanks in advance

  Joe

• Call to avformat_find_stream_info prevents decoding of simple PNG image ?

  10 avril 2014, par kloffy

  I am running into a problem decoding a simple PNG image with libav. The decode_ok flag after the call to avcodec_decode_video2 is set to 0, even though the packet contains the entire image. Through some experimentation, I have managed to pinpoint the issue and it seems related to calling avformat_find_stream_info. If the call is removed, the example runs successfully. However, I would like to use the same code for other media, and calling avformat_find_stream_info is recommended in the documentation.

  The following minimal example illustrates the behavior (unfortunately still a bit lengthy) :

  #include <iostream>
  
  
  
  extern "C"
  
  {
  
  #include <libavformat></libavformat>avformat.h>
  
  #include <libavcodec></libavcodec>avcodec.h>
  
  }
  
  
  
  // Nothing to see here, it&#39;s just a helper function
  
  AVCodecContext* open(AVMediaType mediaType, AVFormatContext* formatContext)
  
  {
  
      auto ret = 0;
  
      if ((ret = av_find_best_stream(formatContext, mediaType, -1, -1, nullptr, 0)) &lt; 0)
  
      {
  
          std::cerr &lt;&lt; "Failed to find video stream." &lt;&lt; std::endl;
  
          return nullptr;
  
      }
  
  
  
      auto codecContext = formatContext->streams[ret]->codec;
  
      auto codec = avcodec_find_decoder(codecContext->codec_id);
  
      if (!codec)
  
      {
  
          std::cerr &lt;&lt; "Failed to find codec." &lt;&lt; std::endl;
  
          return nullptr;
  
      }
  
  
  
      if ((ret = avcodec_open2(codecContext, codec, nullptr)) != 0)
  
      {
  
          std::cerr &lt;&lt; "Failed to open codec context." &lt;&lt; std::endl;
  
          return nullptr;
  
      }
  
  
  
      return codecContext;
  
  }
  
  
  
  // All the interesting bits are here
  
  int main(int argc, char* argv[])
  
  {
  
      auto path = "/path/to/test.png"; // Replace with valid path to PNG
  
      auto ret = 0;
  
  
  
      av_log_set_level(AV_LOG_DEBUG);
  
  
  
      av_register_all();
  
      avcodec_register_all();
  
  
  
      auto formatContext = avformat_alloc_context();
  
      if ((ret = avformat_open_input(&amp;formatContext, path, NULL, NULL)) != 0)
  
      {
  
          std::cerr &lt;&lt; "Failed to open input." &lt;&lt; std::endl;
  
          return -1;
  
      }
  
      av_dump_format(formatContext, 0, path, 0);
  
  
  
  //*/ Info is successfully found, but interferes with decoding
  
      if((ret = avformat_find_stream_info(formatContext, nullptr)) &lt; 0)
  
      {
  
          std::cerr &lt;&lt; "Failed to find stream info." &lt;&lt; std::endl;
  
          return -1;
  
      }
  
      av_dump_format(formatContext, 0, path, 0);
  
  //*/
  
  
  
      auto codecContext = open(AVMEDIA_TYPE_VIDEO, formatContext);
  
  
  
      AVPacket packet;
  
      av_init_packet(&amp;packet);
  
  
  
      if ((ret = av_read_frame(formatContext, &amp;packet)) &lt; 0)
  
      {
  
          std::cerr &lt;&lt; "Failed to read frame." &lt;&lt; std::endl;
  
          return -1;
  
      }
  
  
  
      auto frame = av_frame_alloc();
  
      auto decode_ok = 0;
  
      if ((ret = avcodec_decode_video2(codecContext, frame, &amp;decode_ok, &amp;packet)) &lt; 0 || !decode_ok)
  
      {
  
          std::cerr &lt;&lt; "Failed to decode frame." &lt;&lt; std::endl;
  
          return -1;
  
      }
  
  
  
      av_frame_free(&amp;frame);
  
      av_free_packet(&amp;packet);
  
  
  
      avcodec_close(codecContext);
  
  
  
      avformat_close_input(&amp;formatContext);
  
      av_free(formatContext);
  
  
  
      return 0;
  
  }
  
  </iostream>

  The format dump before avformat_find_stream_info prints :

  Input #0, image2, from '/path/to/test.png' :
    Duration : N/A, bitrate : N/A
      Stream #0:0, 0, 1/25 : Video : png, 25 tbn

  The format dump after avformat_find_stream_info prints :

  Input #0, image2, from '/path/to/test.png' :
    Duration : 00:00:00.04, start : 0.000000, bitrate : N/A
      Stream #0:0, 1, 1/25 : Video : png, rgba, 512x512 [SAR 3780:3780 DAR 1:1], 1/25, 25 tbr, 25 tbn, 25 tbc

  So it looks like the search yields potentially useful information. Can anybody shed some light on this problem ? Other image formats seem to work fine. I assume that this is a simple user error rather than a bug.

  Edit : Debug logging was already enabled, but the PNG decoder does not produce a lot of output. I have also tried setting a custom logging callback.

  Here is what I get without the call to avformat_find_stream_info, when decoding succeeds :

  Statistics : 52125 bytes read, 0 seeks

  And here is what I get with the call to avformat_find_stream_info, when decoding fails :

  Statistics : 52125 bytes read, 0 seeks
  detected 8 logical cores
  

  The image is 52125 bytes, so the whole file is read. I am not sure what the logical cores are referring to.

• ffmpeg Sound going out of sync with -concat or -ss

  6 août 2012, par Jared Glass

  I have a tool that spits out video from a 3D application and then concats the individual videos to make a sequence. But the sound seems to go out of sync in the sequence (the inividual files are fine) and it stutters in VLC and Quicktime. Windows media player seems to handle it bes to my supprise, yet it still goes out of sync. I have two senarios, one works and one doesn't but i need both working :

  Working :
  get already created out movs...

  convert to avi :
  os.system( ffmpeg + " -i C:\clip.mov -sameq -r 24 -y C:\clip.avi")

  concat to avi sequence :
  os.system( ffmpeg + ''' -i concat: C:\clip.avi|C:\clip1.avi|C:\clip2.avi -sameq -r 24 -y C:\sequence.avi''' )

  convert sequence to mov :
  os.system( ffmpeg + " -i C:\sequence.avi -sameq -r 24 -y C:\sequence.mov")

  Not Working :
  create individual avi's from 3D program...

  cut down to correct length :
  os.system(ffmpeg + " -i C:\clip.avi -sameq -r 24 -ss " + startTime + " -vframes " + totalFrames + " -y C:\clip.avi" )

  concat to avi sequence :
  os.system( ffmpeg + ''' -i concat: C:\clip.avi|C:\clip1.avi|C:\clip2.avi -sameq -r 24 -y C:\sequence.avi''' )

  convert sequence to mov :
  os.system( ffmpeg + " -i C:\sequence.avi -sameq -r 24 -y C:\sequence.mov")

  convert individual avi's to mov :
  os.system( ffmpeg + " -i C:\clip.avi-sameq -r 24 -y C:\clip.mov")

  Please let me know where I've gone wrong ?