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• VLC syntax to transcode and stream to stdout ?

  19 novembre 2016, par Will Tower

  Goal : I am trying to use VLC as a local server to expand the video capabilities of an app created with Adobe AIR, Flex and Actionscript. I am using VLC to stream to stdoutand reading that output from within my app.

  VLC Streaming capabilities
  VLC Flash Video
  Stream VLC to Website with asf and Flash

  Status : I am able to launch VLC as a background process and control it through its remote control interface (more detail). I can load, transcode and stream a local video file. The example app below is a barebones testbed demonstrating this.

  Issue : I am getting data in to my app but it is not rendering as video. I don’t know if it is a problem with my VLC commands or with writing to/reading from stdout. This technique of reading from stdout in AIR works (with ffmpeg for example).

  One of the various transcoding commands I have tried :

  -I rc  // remote control interface  
  
  -vvv   // verbose debuging  
  
  --sout  // transcode, stream to stdout 
  
  "#transcode{vcodec=FLV1}:std{access=file,mux=ffmpeg{mux=flv},dst=-}"

  This results in data coming into to my app but for some reason it is not rendering as video when using appendBytes with the NetStream instance.

  If instead I write the data to an .flv file, a valid file is created – so the broken part seems to be writing it to stdout. One thing I have noticed : I am not getting metadata through the stdout`method. If I play the file created with the command below, I do see metadata.

  // writing to a file
  
  var output:File = File.desktopDirectory.resolvePath("stream.flv");
  
  var outputPath:String = output.nativePath;
  
  "#transcode{vcodec=FLV1}:std{access=file,mux=ffmpeg{mux=flv},dst=" + outputPath + "}");

  ---

  Hoping someone sees where I am going wrong here.

  ---

  Update 1 : Just to add some more detail (!) – I took a look at the .flv file that is generated to examine the metadata. It appears at the head of the file as shown below. I have the correct onMetaData handler set up and see a trace of this data if I play the file from disk. I do not see this trace when reading from stdout and NetStream is in Data Generation mode. Is it possible that it isn’t getting sent to stdout for some reason ? I’ve tried generating my own header and appending that before the stream starts – I may not have the header format correct.

  

  ---

  Update 2 : So in my AIR app I was able to crudely parse the incoming stdout stream coming from VLC. I wanted to see if the FLV header data was being sent – and it appears that it is. I don’t know if it is in the correct format, etc. but as I mention above, if I write to an .flv file instead of stdout, a valid .flv file is created.

  Completely at a loss now – have tried everything I could think of and followed up every web link I could find on the issues involved. Alas – so close and it would have been so cool to leverage VLC from within AIR.

• Error decoding timecode using ffprobe

  16 novembre 2016, par Pablo Montilla

  I’m using ffprobe to get timecode from an mxf which has DF timecode but with a non DF frame rate. I’m getting the error Drop frame is only allowed with 30000/1001 or 60000/1001 FPS.

  I’m running ffprobe -i "IMX 10Bit.mxf" and getting the following :

    ffprobe version 3.2 Copyright (c) 2007-2016 the FFmpeg developers
  
      built with gcc 5.4.0 (GCC)
  
      configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-libebur128 --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-decklink --enable-zlib
  
      libavutil      55. 34.100 / 55. 34.100
  
      libavcodec     57. 64.100 / 57. 64.100
  
      libavformat    57. 56.100 / 57. 56.100
  
      libavdevice    57.  1.100 / 57.  1.100
  
      libavfilter     6. 65.100 /  6. 65.100
  
      libswscale      4.  2.100 /  4.  2.100
  
      libswresample   2.  3.100 /  2.  3.100
  
      libpostproc    54.  1.100 / 54.  1.100
  
    [mxf @ 00000000025a3660] Drop frame is only allowed with 30000/1001 or 60000/1001 FPS
  
    Input #0, mxf, from 'IMX 10Bit.mxf':
  
      Metadata:
  
        uid             : 2b3801ea-ec5e-4dc1-ab3a-dba9a2b30ce4
  
        generation_uid  : 2b3801ea-ec5e-4dc2-ab3a-dba9a2b30ce4
  
        product_uid     : 00000000-0000-0000-0000-000000000000
  
        modification_date: 2009-11-04T10:39:42.000000Z
  
        material_package_umid: 0x060A2B340101010501010D43130000005C91020063D700800210F3FFFE154618
  
      Duration: 00:00:19.52, start: 0.000000, bitrate: 62580 kb/s
  
        Stream #0:0: Video: mpeg2video (4:2:2), yuv422p(tv, top first), 720x608 [SAR 152:135 DAR 4:3], 50000 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
  
        Metadata:
  
          file_package_umid: 0x060A2B340101010501010D43130000005D91020063D700800210F3FFFE154618
  
        Stream #0:1: Audio: pcm_s24le, 48000 Hz, 4 channels, s32 (24 bit), 4608 kb/s
  
        Metadata:
  
          file_package_umid: 0x060A2B340101010501010D43130000005D91020063D700800210F3FFFE154618

• ffmpeg problem in ubuntu (libavcodec.so)

  7 décembre 2016, par lyuba

  I run Ubuntu and try to use the ffmpeg wrapper in Java from here :
  http://code.google.com/p/javacv/

  It seems to work fine on other systems, but in Ubuntu the project crashes
  with the following mistake :
  Exception in thread "main" java.lang.UnsatisfiedLinkError : Error looking up
  function ’avcodec_decode_video2’ : /usr/lib/i686/cmov/libavcodec.so :
  undefined symbol : avcodec_decode_video2

  ffmpeg is working great from the command line, though.

  JavaCV author recommended me to check this link :
  http://linux-tipps.blogspot.com/2009/05/pretending-package-is-installed-by.html

  Probably I’m doing something wrong, but it cannot reinstall libavcodec51
  like this.

  So the questions are :
  1. Is those solution above a good one so I should bring it to success
  somehow ?
  2. What are the other ways to solve the problem ?

  Thank you for your suggestions in advance !