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• Carrierwave-video "Process hung" error while encoding uncompressed video files

  28 avril 2014, par Cramps

  I have an API for a mobile app that accepts video uploads. This app is for both iOS and Android devices, so for video compatibility’s sake these videos are encoded to H.264 once uploaded to the server using carrierwave-video (ffmpeg wrapper gem for Ruby on Rails). Right now this seems to be working, and videos are uploaded and encoded and can be played in both Android and iOS devices. However, sometimes the process hangs while encoding heavy (uncompressed ?) video files, usually 10+ seconds long. This is the output of ffmpeg :

  Failed to transcode with FFmpeg.
  
  Check ffmpeg install and verify video is not corrupt or cut short.
  
  Original error: Process hung. Full output: 

  (That’s it, the full output seems empty.)

  These are the encoding parameters I’m using in my Carrierwave Uploader :

  encode_video(:mp4, custom: '-y -vcodec libx264 -acodec libfaac -vpre ultrafast 2> /home/user/log/ffmpeg.log, resolution: '640x640')

  According to the SuperUser question I linked above a solution would be to encode the video twice, once to AVI for compression(?) and then encode to MP4. I don’t know if that would work, but I don’t know how to do this either in my uploader. I would have to encode the output video file of my first (AVI) encoding process.

  Now that there’s some context, my question is : How can I solve this "Process hung" error ?

  In case the answer to that is to go with this double encoding method suggested, how can I achieve this using Carrierwave-video ?

  One last note is that if I try to encode these videos using ffmpeg straight from command-line the videos encode and playback successfully.

  Thank you for your time !

  PD : Wasn’t sure if I should add ruby-on-rails tag. I’ll remove it if necessary !

  Edit
  This is what I get from ffmpeg -i filename.mp4

  ffmpeg version 0.10.3 Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Apr 30 2013 11:26:53 with gcc 4.5.4
  
    configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --mandir=/usr/share/man --enable-shared --cc=x86_64-pc-linux-gnu-gcc --cxx=x86_64-pc-linux-gnu-g++ --ar=x86_64-pc-linux-gnu-ar --optflags='-O2 -march=athlon64 -pipe' --extra-cflags='-O2 -march=athlon64 -pipe' --extra-cxxflags='-O2 -march=athlon64 -pipe' --disable-static --enable-gpl --enable-version3 --enable-postproc --enable-avfilter --disable-stripping --disable-debug --disable-doc --disable-vaapi --disable-vdpau --disable-ffplay --enable-openssl --enable-nonfree --enable-libmp3lame --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --enable-libaacplus --enable-nonfree --enable-libfaac --enable-nonfree --disable-indev=v4l --disable-indev=v4l2 --disable-indev=alsa --disable-indev=oss --disable-indev=jack --disable-outdev=alsa --disable-outdev=oss --disable-outdev=sdl --enable-pthreads --enable-libopencore-amrwb --enable-libopencore-amrnb --enable-libvpx --enable-libope  libavutil      51. 35.100 / 51. 35.100
  
    libavcodec     53. 61.100 / 53. 61.100
  
    libavformat    53. 32.100 / 53. 32.100
  
    libavdevice    53.  4.100 / 53.  4.100
  
    libavfilter     2. 61.100 /  2. 61.100
  
    libswscale      2.  1.100 /  2.  1.100
  
    libswresample   0.  6.100 /  0.  6.100
  
    libpostproc    52.  0.100 / 52.  0.100
  
  
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/home/user/api/uploads/tmp/e54zfghzt9.mp4':
  
  
  
  
  
  Metadata:
  
      major_brand     : isom
  
      minor_version   : 0
  
      compatible_brands: isom3gp4
  
      creation_time   : 2014-04-23 14:56:19
  
    Duration: 00:00:14.27, start: 0.000000, bitrate: 20757 kb/s
  
      Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080, 20993 kb/s, SAR 65536:65536 DAR 16:9, 30 fps, 30 tbr, 90k tbn, 180k tbc
  
  
  
  
  
  Metadata:
  
        creation_time   : 2014-04-23 14:56:19
  
        handler_name    : VideoHandle
  
      Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, s16, 190 kb/s
  
  
  
  
  
  Metadata:
  
        creation_time   : 2014-04-23 14:56:19
  
        handler_name    : SoundHandle

  Then it just starts buffering as such :

  time=00:00:13.20 bitrate=2533.2kbits/s    
  
  frame=  405 fps=  7 q=24.0 size=    4083kB time=00:00:13.20 bitrate=2533.2kbits/s    
  
  frame=  407 fps=  7 q=24.0 size=    4083kB time=00:00:13.20 bitrate=2533.2kbits/s    
  
  frame=  409 fps=  7 q=24.0 size=    4083kB time=00:00:13.20 bitrate=2533.2kbits/s    
  
  frame=  412 fps=  7 q=24.0 size=    4083kB time=00:00:13.20 bitrate=2533.2kbits/s    
  
  frame=  417 fps=  7 q=24.0 size=    4083kB time=00:00:13.20 bitrate=2533.2kbits/s    
  
  frame=  417 fps=  7 q=24.0 Lsize=    4194kB time=00:00:13.90 bitrate=2471.5kbits/s    
  
  video:3957kB audio:223kB global headers:0kB muxing overhead 0.310939%
  
  [libx264 @ 0x7f28327ccc50] frame I:2     Avg QP:21.50  size: 25120
  
  [libx264 @ 0x7f28327ccc50] frame P:415   Avg QP:25.32  size:  9642
  
  [libx264 @ 0x7f28327ccc50] mb I  I16..4: 35.8%  0.0% 64.2%
  
  [libx264 @ 0x7f28327ccc50] mb P  I16..4:  8.4%  0.0%  3.2%  P16..4: 43.6% 19.0%  5.6%  0.0%  0.0%    skip:20.2%
  
  [libx264 @ 0x7f28327ccc50] coded y,uvDC,uvAC intra: 45.2% 53.6% 27.3% inter: 39.4% 27.6% 2.7%
  
  [libx264 @ 0x7f28327ccc50] i16 v,h,dc,p: 28% 57% 11%  5%
  
  [libx264 @ 0x7f28327ccc50] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 14% 66% 11%  1%  1%  1%  2%  1%  2%
  
  [libx264 @ 0x7f28327ccc50] i8c dc,h,v,p: 23% 58% 17%  3%
  
  [libx264 @ 0x7f28327ccc50] kb/s:2331.88

  `

• OpenCV and RTMP

  28 mai 2014, par user2723463

  I want to be able to create an application that can read and publish an RTMP stream.

  Using OpenCV i could read rtp due to it’s ffmpeg backend.

  Stream video from ffmpeg and capture with OpenCV

  C++ RTMP is another possibility, but this is an RTMP server so it mainly requests and sends files. Although open source, i am unsure how to build or integrate this into a Visual Studio application in such a way as to make the function calls available to my project.

  OTher sources indicate that OpenCV’s RTSP isn’t great.

  http://workingwithcomputervision.blogspot.co.nz/2012/06/issues-with-opencv-and-rtsp.html

  How can you run a streaming server, such as RTMP C++ and get the raw data out. OpenCV can encode and decode image data for streaming, but how can you link the two ?

  Could a C++ application pipe a stream together ? How could i interface with that stream to send it more images ? Also, for receiving images ?

  Regards,

• Missing reference frame, slice header decode error

  20 juin 2014, par AnilJ

  I split this (http://www.auby.no/files/video_tests/h264_720p_mp_3.1_3mbps_aac_shrinkage.mp4) video using mp4box command "MP4Box -split 1 shrinking.mp4" into slices of 1 second each. I have following questions :

  1. I got different sizes of the video although I sliced it evenly at 1 second. Not sure how this happened ?
  2. When I try to dump the information about the video slice file, I get the below message with an error. Can someone please help me understand what it is, and how possibly I can modify the command above to get rid of it ? This error occurs for every video slide generated. This error comes only on the sliced videos.

  Thanks,
  /anil.

  anilj@desk1:~/workspace/testprogs/shellscripts$ ffmpeg -i invideo/shrinking_01.mp4
  
  ffmpeg version N-36083-g2501f93-xuggle-5.5 Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Jun  3 2014 13:43:04 with gcc 4.6.4
  
    configuration: --prefix=/home/anilj/workspace/xugglehome --extra-version=xuggle-5.5 --extra-cflags=-I/home/anilj/workspace/xuggle-xuggler/build/native/x86_64-unknown-linux-gnu/captive/stage/home/anilj/workspace/xugglehome/include --extra-ldflags=-L/home/anilj/workspace/xuggle-xuggler/build/native/x86_64-unknown-linux-gnu/captive/stage/home/anilj/workspace/xugglehome/lib --disable-shared --enable-pic --enable-gpl --enable-nonfree --enable-libx264 --enable-version3 --enable-libmp3lame --enable-libvorbis --enable-libtheora --enable-libspeex --enable-libvo-aacenc --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-librtmp --enable-openssl --enable-zlib --enable-libvpx
  
    libavutil      51. 46.100 / 51. 46.100
  
    libavcodec     54. 14.101 / 54. 14.101
  
    libavformat    54.  3.100 / 54.  3.100
  
    libavdevice    53.  4.100 / 53.  4.100
  
    libavfilter     2. 67.101 /  2. 67.101
  
    libswscale      2.  1.100 /  2.  1.100
  
    libswresample   0. 10.100 /  0. 10.100
  
    libpostproc    52.  0.100 / 52.  0.100
  
  [h264 @ 0x1ddeac0] Missing reference picture
  
  [h264 @ 0x1ddeac0] decode_slice_header error
  
  [h264 @ 0x1ddeac0] Missing reference picture
  
  [h264 @ 0x1ddeac0] decode_slice_header error
  
  [h264 @ 0x1ddeac0] Missing reference picture
  
  [h264 @ 0x1ddeac0] decode_slice_header error
  
  [h264 @ 0x1ddeac0] Missing reference picture
  
  [h264 @ 0x1ddeac0] decode_slice_header error
  
  [h264 @ 0x1ddeac0] concealing 3600 DC, 3600 AC, 3600 MV errors
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'invideo/shrinking_01.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 1
  
      compatible_brands: isom
  
      creation_time   : 2014-06-19 20:21:02
  
    Duration: 00:00:00.90, start: 0.000000, bitrate: 38 kb/s
  
      Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 30 kb/s, 29.96 fps, 29.96 tbr, 29956 tbn, 59.92 tbc
  
      Metadata:
  
        creation_time   : 2011-05-05 18:09:35
  
        handler_name    : ?Apple Video Media Handler
  
  At least one output file must be specified