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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)

• Split video file from 'n' th frame to end of video in Linux

  17 novembre 2011, par Skkard

  I need to split a video file using frames as the measure, e.g. I need to save the part of the video from the 34th frame to the end of the video in Linux( specifically fedora 16, xfce, 64bit ).

  I've tried using ffmpeg, using the '-vframes' option to specify how many frames to save, but it starts from the beginning, so is not that useful. How can I start from a certain frame in between the video and save the video from there to the end in a new file.

  I know about the '-ss' option, but while converting number of frames to the specified time, there might be errors( or so I believe. Please correct me if I'm wrong ) due to rounding.

  Could you please suggest a method ? Thanks !

• HTML5 Video FFMPEG Shell Script

  18 novembre 2011, par Schermy

  I wrote this quick and dirty shell script to run ffmpeg over a bunch of files to generate webm/ogg/h.264 videos for a HTML5 site.

  #!/bin/bash
  
  
  
  ext=$1
  
  enc=$2
  
  
  
  #!/bin/bash
  
  for file in *.$ext; do
  
          while pidof /usr/local/bin/ffmpeg; do sleep 10; done >/dev/null
  
  
  
          ffmpeg -i "$file" -s 1280x720 -b 500k  "${file/%$ext/$enc}"   
  
  done

  It works great for my purposes but I've noticed that each video now takes a lot longe to convert and ffmpeg is not taking advantage of my multi-core setup.

  I would like to improve this script when I have some time and make it available for use by others but I'd like to solve this issue first.

  Thanks in advance for all of your help.

  P.S. This is setup to use the ffmpeg installation from brew on the Mac (and yes I would like to make this script more platform agnostic later on).