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• Missing audio and problems playing FLV video converted from 720p .mov file with FFMPEG

  18 novembre 2011, par undefined

  I have some .mov video files recorded from a JVC GC-FM1 HD video camera in 720p mode. I have FFMPEG running on a Linux box that I upload files to for encoding into FLV format. The video appears to be encoding ok, but there is no audio in the resulting FLV file. Also, when I play it back in Flash Player, in a browser or on Adobe Media Player, the video pauses at the start. It appears that Adobe Media Player waits for the progress bar to reach the end of the video before starting the playback - i.e. the video will load, the picture pauses, the progress bar seeks to the end as if the video were playing, then when it reaches the end the video picture starts. There is no audio on the video. I am noticing this in the video player I have built with Flash 8 using an FLVPlayback component and attached seekBar. The seek bar will start moving as if the video is playing but the picture remains paused.

  Here are some outputs from my FFMPEG log and the command I am using to encode the video.

  My FFMPEG command called from PHP :

  $cmd = 'ffmpeg -i ' . $sourcelocation.$filename.".".$fileext . '  -ab 96k -b 700k \
  
  -ar 44100 -s ' . $target['width'] . 'x' . $target['height'] . ' -ac 1 \
  
  -acodec libfaac ' . $destlocation.$filename.$ext_trans .' 2>&1';

  The output from my error log :

  FFmpeg version UNKNOWN, Copyright (c) 2000-2010 Fabrice Bellard, et al.
  
  built on Jan 22 2010 11:31:03 with gcc 4.1.2 20070925 (Red Hat 4.1.2-33)
  
  configuration: --prefix=/usr --enable-static --enable-shared --enable-gpl \
  
  --enable-nonfree --enable-postproc --enable-avfilter --enable-avfilter-lavf \
  
  --enable-libfaac --enable-libfaad --enable-libfaadbin --enable-libgsm \
  
  --enable-libmp3lame --enable-libvorbis --enable-libx264
  
  libavutil     50. 7. 0 / 50. 7. 0
  
  libavcodec    52.48. 0 / 52.48. 0
  
  libavformat   52.47. 0 / 52.47. 0
  
  libavdevice   52. 2. 0 / 52. 2. 0
  
  libavfilter    1.17. 0 /  1.17. 0
  
  libswscale     0. 9. 0 /  0. 9. 0
  
  libpostproc   51. 2. 0 / 51. 2. 0
  
  
  
  Seems stream 0 codec frame rate differs from container frame rate: 119.88 (120000/1001) -> 59.94 (60000/1001)
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'uploads/video/60974_v1.mov':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 0
  
      compatible_brands: qt  
  
      comment         : JVC GC-FM1
  
      comment-eng     : JVC GC-FM1
  
    Duration: 00:00:30.41, start: 0.000000, bitrate: 4158 kb/s
  
      Stream #0.0(eng): Video: h264, yuv420p, 640x480 [PAR 1:1 DAR 4:3], 4017 kb/s, 59.94 fps, 59.94 tbr, 90k tbn, 119.88 tbc
  
      Stream #0.1(eng): Audio: aac, 48000 Hz, stereo, s16, 128 kb/s
  
  Output #0, rawvideo, to 'uploads/video/60974_v1.jpg':
  
      Stream #0.0(eng): Video: mjpeg, yuvj420p, 320x240 [PAR 1:1 DAR 4:3], q=2-31, 200 kb/s, 90k tbn, 59.94 tbc
  
  Stream mapping:
  
    Stream #0.0 -> #0.0
  
  Press [q] to stop encoding
  
  [h264 @ 0x8e67930]B picture before any references, skipping
  
  [h264 @ 0x8e67930]decode_slice_header error
  
  [h264 @ 0x8e67930]no frame!
  
  Error while decoding stream #0.0
  
  [h264 @ 0x8e67930]B picture before any references, skipping
  
  [h264 @ 0x8e67930]decode_slice_header error
  
  [h264 @ 0x8e67930]no frame!
  
  Error while decoding stream #0.0
  
  frame=    1 fps=  0 q=3.8 Lsize=      15kB time=0.02 bitrate=7271.4kbits/s dup=482 drop=0    
  
  video:15kB audio:0kB global headers:0kB muxing overhead 0.000000%

  Which are the important errors here ?

  B picture before any references, skipping ?
  decode_slice_header error ?
  no frame ?
  or
  Seems stream 0 codec frame rate differs from container frame rate : 119.88 (120000/1001) -> 59.94 (60000/1001)

• How to create a youtube like preview of video ?

  11 juin 2012, par Udhay

  How to create a youtube like video preview ? That is in youtube, it is showing the preview of the video when we mouseover the progress bar ? How to do that kind of preview using ffmpeg or mencoder or is there any other way to do that ? Have a look at this image. Please go here for a live preview.

  http://www.youtube.com/watch?v=yto4_QFoLdA&feature=watch-now-button&wide=1

• Mixing a FLV audio stream with a WAV background track, and converting to MP3 with SoX and FFmpeg

  7 septembre 2012, par tubbo

  I'm building a Flash-based recording application for a contracted web site. It streams the recorded voice (via SWF) to a Red5 server, then uses a combination of FFmpeg and SoX to compile the vocal audio with a lower-in-volume background music track. This all has to happen on-demand, that is, when a user "saves" his or her vocal recording.

  Here is an example command I will be running. Names have been changed to protect the innocent. The filenames describe their role in the final file :

  sox --combine mix -p --no-show-progress --norm "|ffmpeg -i /usr/share/red5/webapps/audiorecorder/stream/SPOKEN_VOICE.flv -t wav pipe:1" /var/www/ufiles/music/BACKGROUND_MUSIC.wav - | ffmpeg -i pipe:1 /var/www/ufiles/recordings/COMPILED_AUDIO_RECORDING.mp3

  When I run this command in the shell, this is what happens :

  $ sox --combine mix -p --no-show-progress --norm "|ffmpeg -i audioStream_1321399534128_21.flv -ar 44100 -ac 2 -t wav pipe:1" wrong.wav - | ffmpeg -i pipe:1 ~/www/trauma101.com/compiled.mp3
  
  ffmpeg version N-34884-g7575980, Copyright (c) 2000-2011 the FFmpeg developers
  
    built on Nov 15 2011 14:06:49 with gcc 4.4.5
  
    configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-postproc --enable-libfaac --enable-libmp3lame --enable-libx264 --enable-x11grab --enable-libspeex
  
    libavutil    51. 25. 0 / 51. 25. 0
  
    libavcodec   53. 34. 0 / 53. 34. 0
  
    libavformat  53. 20. 0 / 53. 20. 0
  
    libavdevice  53.  4. 0 / 53.  4. 0
  
    libavfilter   2. 48. 1 /  2. 48. 1
  
    libswscale    2.  1. 0 /  2.  1. 0
  
    libpostproc  51.  2. 0 / 51.  2. 0
  
  ffmpeg version N-34884-g7575980, Copyright (c) 2000-2011 the FFmpeg developers
  
    built on Nov 15 2011 14:06:49 with gcc 4.4.5
  
    configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-postproc --enable-libfaac --enable-libmp3lame --enable-libx264 --enable-x11grab --enable-libspeex
  
    libavutil    51. 25. 0 / 51. 25. 0
  
    libavcodec   53. 34. 0 / 53. 34. 0
  
    libavformat  53. 20. 0 / 53. 20. 0
  
    libavdevice  53.  4. 0 / 53.  4. 0
  
    libavfilter   2. 48. 1 /  2. 48. 1
  
    libswscale    2.  1. 0 /  2.  1. 0
  
    libpostproc  51.  2. 0 / 51.  2. 0
  
  [libspeex @ 0x1e36b20] Missing Speex header, assuming defaults.
  
  Input #0, flv, from 'audioStream_1321399534128_21.flv':
  
    Metadata:
  
      novideocodec    : 0
  
      server          : Red5 Server 1.0.0 RC2 Rev: 4295
  
      creationdate    : Tue Nov 15 15:25:41 PST 2011
  
      canSeekToEnd    : true
  
    Duration: 00:00:06.77, start: 0.000000, bitrate: 43 kb/s
  
      Stream #0:0: Audio: speex, 16000 Hz, 1 channels, s16
  
  Invalid duration specification for t: wav
  
  sox FAIL formats: can't open input pipe `|ffmpeg -i audioStream_1321399534128_21.flv -ar 44100 -ac 2 -t wav pipe:1': premature EOF

  I think the issue is stemming from the conversion from FLV to WAV in FFmpeg, and since it's being piped in it causes the whole process to fail. I always get that duration warning, but when FFmpeg outputs to a .wav file and the SoX command is run separately, I can still get a WAV from SoX and convert that to MP3 manually. I'd like to do all this in one line, piping the data between applications.

  What do I do ?