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• Android ffmpeg simple JNI wrapper

  12 octobre 2012, par user1504495

  I've been trying to use an ffmpeg binary with command line access for a while now and getting nowhere (Using runtime.exec)
  It looks like the only way I'll be able to get it to work is using a wrapper in C to access the built ffmpeg libraries using JNI...
  Main problem : I haven't coded C for more than one and a half decades now and wouldn't know where to begin...

  I just need 3 operations, I need to add audio to a video file, I need to concatenate two video files and if possible I need to rotate a clip by 90 degrees (but I could do without this)...

  Does anyone have any example code that could work for me, or some good places to start (I've already exhausted much of the first pages of various google results to no avail)...

  Any help would be greatly appreciated !

• accurate cutting of video (+ audio) with ffmpeg [migrated]

  4 novembre 2012, par Pete Oakey

  I want my website to allow users to accurately create their own clips from a source video I provide.

  I have a source video file that I first want to convert to something suitable for a website :

  Input #0, matroska,webm, from 'source.mkv': 
  
  Duration: 00:28:18.57, start: 0.000000, bitrate: 10183 kb/s 
  
  Stream #0:0: Video: h264 (Constrained Baseline), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn, 48 tbc (default)
  
  Stream #0:1: Audio: mp3, 44100 Hz, stereo, s16, 128 kb/s (default)

  So I use ffmpeg to convert it like so :

  ffmpeg -i source.mkv -c:v libx264 -c:a aac -strict experimental -vf scale="960:-1" source.mp4

  Watching this video back it is good enough quality and small enough file size for my needs, and loads/plays on my website.

  So I have a webpage that lets users select a start and endpoint on this video - and create a clip. Here's an example of the ffmpeg command that I use for that :

  -ss 577.920 -i source.mp4 -t 011.980 -codec:v copy -codec:a copy -vf scale="960:-1" clip1.mp4

  The problem is the clip is not always time-accurate enough. Usually the audio is accurate enough but the video stops half a second early or something.

  Is there any way to make this accurate and in-sync to say, 0.2 of a second ?

  EDIT :
  Adding -force_key_frames 00:00:00.2 didn't help.

• ffmpeg, video Conversion

  7 novembre 2012, par user1805414

  I have 2 video.
  Metadata files :

  Seems stream 0 codec frame rate differs from container frame rate: 2000.00 (2000/1) -> 30.00 (30/1)
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '89.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 0
  
      compatible_brands: mp41isom
  
      creation_time   : 2012-10-23 08:10:51
  
    Duration: 00:00:08.96, start: 0.000000, bitrate: 2017 kb/s
  
      Stream #0.0(eng): Video: h264 (Baseline), yuv420p, 640x480, 2006 kb/s, 28.53 fps, 30 tbr, 1k tbn, 2k tbc
  
      Metadata:
  
        creation_time   : 2012-10-23 08:10:51
  
      Stream #0.1(eng): Audio: aac, 48000 Hz, stereo, s16, 48 kb/s
  
      Metadata:
  
        creation_time   : 2012-10-23 08:10:51
  
  At least one output file must be specified.
  
  //--------------------------------------------------------------------------------------------------------------//
  
  Seems stream 1 codec frame rate differs from container frame rate: 180000.00 (180000/1) -> 90000.00 (180000/2)
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '56_1.mp4':
  
    Metadata:
  
      major_brand     : 3gp4
  
      minor_version   : 0
  
      compatible_brands: isom3gp4
  
      creation_time   : 1946-11-02 07:14:31
  
    Duration: 00:00:05.23, start: 0.000000, bitrate: 239 kb/s
  
      Stream #0.0(eng): Audio: amrnb, 8000 Hz, 1 channels, flt, 5 kb/s
  
      Metadata:
  
        creation_time   : 1946-11-02 07:14:31
  
      Stream #0.1(eng): Video: h264 (Baseline), yuv420p, 480x320, 240 kb/s, PAR 65536:65536 DAR 3:2, 17.63 fps, 90k tbr, 90k tbn, 180k tbc
  
      Metadata:
  
        creation_time   : 1946-11-02 07:14:31
  
  At least one output file must be specified.

  They do not play on my website.
  How to bring them to a form ?

  Seems stream 0 codec frame rate differs from container frame rate: 47.95 (5994/125) -> 23.98 (24000/1001)
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'oceans-clip.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 1
  
      compatible_brands: isomavc1
  
      creation_time   : 2010-05-18 04:24:00
  
    Duration: 00:00:46.54, start: 0.000000, bitrate: 3342 kb/s
  
      Stream #0.0(und): Video: h264 (Constrained Baseline), yuv420p, 640x264 [PAR 132:133 DAR 320:133], 3195 kb/s, PAR 127:128 DAR 635:264, 23.98 fps, 23.98 tbr, 24k tbn, 47.95 tbc
  
      Metadata:
  
        creation_time   : 2010-05-18 04:24:00
  
      Stream #0.1(und): Audio: aac, 44100 Hz, stereo, s16, 144 kb/s
  
      Metadata:
  
        creation_time   : 2010-05-18 04:24:01
  
  At least one output file must be specified

  I get the video to android and vinfone devices, and must play it on your site, but the player does not want to play. Metadata files that I get see the beginnings. The latter belongs to the metadata file that correctly reproduced on the site.