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• How to read .mp4 files in opencv

  9 mai 2016, par Noah

  I am totally newbie in OpenCV, C++. Trying to read an mp4 video but found OpenCV does not support mp4, it only reads avi(I am not sure whether I am write or wrong). After an online research came to know ffmpeg is the best option to convert mp4 to avi for further processing.

  I am using OpenCV 3.0 with visual studio 2012. I saw there is a dll file, opencv_ffmpeg300.dll in OpenCV C:\opencv\build\x86\vc11\bin folder. Is there any way I can use this dll file to read and convert my video ?

  It will be really appreciating if someone can provide me some guidelines, I am lost in the OpenCV world totally.

  For video,

  Video I/O:
  
     Video for Windows:           YES
  
     DC1394 1.x:                  NO
  
     DC1394 2.x:                  NO
  
     FFMPEG:                      YES (prebuilt binaries)
  
       codec:                     YES (ver 55.18.102)
  
       format:                    YES (ver 55.12.100)
  
       util:                      YES (ver 52.38.100)
  
       swscale:                   YES (ver 2.3.100)
  
       resample:                  NO
  
       gentoo-style:              YES
  
     OpenNI:                      NO
  
     OpenNI PrimeSensor Modules:  NO
  
     OpenNI2:                     NO
  
     PvAPI:                       NO
  
     GigEVisionSDK:               NO
  
     DirectShow:                  YES
  
     Media Foundation:            NO
  
     XIMEA:                       NO
  
     Intel PerC:                  NO

• Getting 'av_interleaved_write_frame() : Broken pipe' error

  2 juillet 2016, par Poornan

  I am trying this blog post.I am new to python, numpy as well as FFMPEG. I could not figure out what causes this issue.

  http://zulko.github.io/blog/2013/09/27/read-and-write-video-frames-in-python-using-ffmpeg/

  here is the code :

  import subprocess as sp
  
  import numpy
  
  
  
  print ("Hello World!");
  
  FFMPEG_BIN = "ffmpeg" # on Linux ans Mac OS
  
  #FFMPEG_BIN = "ffmpeg.exe" # on Windows
  
  
  
  command = [ FFMPEG_BIN,
  
              '-i', '/Users/eananthaneshan/Movies/myvideo.mp4',
  
              '-f', 'image2pipe',
  
              '-pix_fmt', 'yuv444p',
  
              '-s', '420x360',
  
              '-r', '24',
  
              '-vcodec', 'h264', '-']
  
  pipe = sp.Popen(command, stdout = sp.PIPE, bufsize=-1)
  
  
  
  # read 420*360*3 bytes (= 1 frame)
  
  raw_image = pipe.stdout.read(420*360*3)
  
  # transform the byte read into a numpy array
  
  image =  numpy.fromstring(raw_image, dtype='uint8')
  
  image = image.reshape((360,420,3)   )
  
  # throw away the data in the pipe's buffer.
  
  pipe.stdout.flush()

  This is the output :

  ffmpeg version 2.8 Copyright (c) 2000-2015 the FFmpeg developers
  
    built with Apple LLVM version 7.0.0 (clang-700.0.72)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/2.8 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-opencl --enable-libx264 --enable-libmp3lame --enable-libvo-aacenc --enable-libxvid --enable-libfreetype --enable-libtheora --enable-libvorbis --enable-libvpx --enable-librtmp --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libass --enable-ffplay --enable-libspeex --enable-libschroedinger --enable-libfdk-aac --enable-libopus --enable-frei0r --enable-libopenjpeg --disable-decoder=jpeg2000 --extra-cflags='-I/usr/local/Cellar/openjpeg/1.5.2_1/include/openjpeg-1.5 ' --enable-nonfree --enable-vda
  
    libavutil      54. 31.100 / 54. 31.100
  
    libavcodec     56. 60.100 / 56. 60.100
  
    libavformat    56. 40.101 / 56. 40.101
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5. 40.101 /  5. 40.101
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  2.101 /  1.  2.101
  
    libpostproc    53.  3.100 / 53.  3.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/Users/eananthaneshan/Movies/myvideo.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 1
  
      compatible_brands: isom
  
      creation_time   : 2014-04-07 02:02:31
  
    Duration: 01:00:10.03, start: 0.000000, bitrate: 1024 kb/s
  
      Stream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 111 kb/s (default)
  
      Metadata:
  
        creation_time   : 2014-04-07 02:02:31
  
        handler_name    : GPAC ISO Audio Handler
  
      Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709/unknown/unknown), 720x404, 909 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 47.95 tbc (default)
  
      Metadata:
  
        creation_time   : 2014-04-07 01:14:58
  
        handler_name    : L-SMASH Video Media Handler
  
        encoder         : AVC Coding
  
  Output #0, image2pipe, to 'pipe:':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 1
  
      compatible_brands: isom
  
      encoder         : Lavf56.40.101
  
      Stream #0:0(und): Video: rawvideo (444P / 0x50343434), yuv444p, 420x360, q=2-31, 200 kb/s, 23.98 fps, 23.98 tbn, 23.98 tbc (default)
  
      Metadata:
  
        creation_time   : 2014-04-07 01:14:58
  
        handler_name    : L-SMASH Video Media Handler
  
        encoder         : Lavc56.60.100 rawvideo
  
  Stream mapping:
  
    Stream #0:1 -> #0:0 (h264 (native) -> rawvideo (native))
  
  Press [q] to stop, [?] for help
  
  av_interleaved_write_frame(): Broken pipe
  
  frame=    2 fps=0.0 q=-0.0 Lsize=     886kB time=00:00:00.08 bitrate=87003.8kbits/s    
  
  video:886kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.000000%
  
  Conversion failed!

• Capturing frames from an h264 stream with gst/ffmpeg

  17 août 2016, par Yuval.Sightec

  I want to save (as jpegs) or reach the data of the frames streaming from my usb camera.
  Meaning that I want to use the h.264 hardware encoding (I running it on nvdia jetson) in order to get a sequence of compressed files (I prefer not save it on the disc and get an array, if possible).
  Can I do that ?

  So far I tried this :

  gst-launch-1.0 -v v4l2src device=/dev/video0 ! video/x-h264,framerate=30/1,stream-format=byte-stream ! decodebin ! videorate ! video/x-raw,framerate=30/1 ! videoconvert ! jpegenc ! multifilesink location=img_%04d.jpg

  but I get an internal data flow error from v4l2src0 element, and an error from gst_base_src_loop() after the pipeline was set to PLAYING.

  Can anybody please help me ?

  b.t.w- It doesnt have to be neccecerly h.264 encoding, it also can be mpeg encoding or something else : I want to use the fact that it is pictures of a video, frames, in order to get smaller size frames.

  Thank you so much !