Recherche avancée

Sur d’autres sites (10737)

• How to convert audio file using ffmpeg API ?

  5 novembre 2011, par zvoice

  How to convert PCM to flac using only ffmpeg API, but not the ffmpeg binary ? I am looking for the full explanation of the process, but not only a solution

• ffmpeg : convert audio-only flv to swf

  5 octobre 2011, par Michael Brewer-Davis

  My Flex application records audio-only FLV files using red5—I'd like to convert these to SWF files so I can embed them in other SWF files. (I could also convert to MP3 and then embed them into SWFs myself, but I'd prefer a one step solution.)

  Anyone have experience doing this ?

  What I've tried :

  The following naive ffmpeg command fails :

  > ffmpeg -i 3139747641.flv -vn movie.swf
  
  FFmpeg version SVN-r21751-snapshot, Copyright (c) 2000-2010 Fabrice Bellard, et al.
  
    built on Feb 11 2010 09:15:42 with gcc 4.2.1 (SUSE Linux)
  
    configuration: --enable-gpl --enable-nonfree
  
    libavutil     50. 9. 0 / 50. 9. 0
  
    libavcodec    52.53. 0 / 52.53. 0
  
    libavformat   52.52. 0 / 52.52. 0
  
    libavdevice   52. 2. 0 / 52. 2. 0
  
    libswscale     0.10. 0 /  0.10. 0
  
  [flv @ 0x8a5e3a0]Could not find codec parameters (Video: 0x0000)
  
  [flv @ 0x8a5e3a0]Estimating duration from bitrate, this may be inaccurate
  
  Input #0, flv, from '3139747641.flv':
  
    Metadata:
  
      audiocodecid    : -1
  
      duration        : 0
  
      videocodecid    : -1
  
      canSeekToEnd    : true
  
    Duration: 00:00:14.88, start: 0.000000, bitrate: N/A
  
      Stream #0.0: Video: 0x0000, 1k tbr, 1k tbn, 1k tbc
  
      Stream #0.1: Audio: nellymoser, 8000 Hz, mono, s16
  
  Output #0, swf, to 'movie.swf':
  
      Stream #0.0: Audio: 0x0000, 8000 Hz, mono, s16, 64 kb/s
  
  Stream mapping:
  
    Stream #0.1 -> #0.0
  
  Encoder (codec id 86017) not found for output stream #0.0

  I've tried adding a dummy video, but this also failed :

  > ffmpeg -i dummy.mov -i 3139747641.flv movie.swf
  
      
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'dummy.mov':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 512
  
      compatible_brands: qt  
  
      encoder         : Lavf52.52.0
  
      encoder-eng     : Lavf52.52.0
  
    Duration: 00:00:00.10, start: 0.000000, bitrate: 62 kb/s
  
      Stream #0.0(eng): Video: mpeg4, yuv420p, 10x10 [PAR 1:1 DAR 1:1], 1 kb/s, 10 fps, 10 tbr, 10 tbn, 10 tbc
  
  [flv @ 0x8a67fa0]Could not find codec parameters (Video: 0x0000)
  
  [flv @ 0x8a67fa0]Estimating duration from bitrate, this may be inaccurate
  
  Input #1, flv, from '3139747641.flv':
  
    Metadata:
  
      audiocodecid    : -1
  
      duration        : 0
  
      videocodecid    : -1
  
      canSeekToEnd    : true
  
    Duration: 00:00:14.88, start: 0.000000, bitrate: N/A
  
      Stream #1.0: Video: 0x0000, 1k tbr, 1k tbn, 1k tbc
  
      Stream #1.1: Audio: nellymoser, 8000 Hz, mono, s16
  
  picture size invalid (0x0)
  
  Cannot allocate temp picture, check pix fmt

• Streaming without Content-Length in response

  29 août 2011, par kain

  I'm using Node.js, Express (and connect), and fluent-ffmpeg.

  We want to stream audio files that are stored on Amazon S3 through http.

  We have all working, except that we would like to add a feature, the on-the-fly conversion of the stream through ffmpeg.

  This is working well, the problem is that some browsers checks in advance before actually getting the file.

  Incoming requests containing the Range header, for which we reply with a 206 with all the info from S3, have a fundamental problem : we need to know in advance the content-length of the file.

  We don't know that since it is going through ffmpeg.

  One solution might be to write out the resulting content-length directly on S3 when storing the file (in a special header), but this means we have to go through the pain of having queues to encode after upload just to know the size for future requests.
  It also means that if we change compressor or preset we have to go through all this over again, so it is not a viable solution.

  We also noticed big differencies in the way Chrome and Safari request the audio tag src, but this may be discussion for another topic.

  Fact is that without a proper content-length header in response everything seems to break or browsers goes in an infinite loop or restart the stream at pleasure.

  Ideas ?