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• Merge commit ’4f03a77e52596cbe9ec179666ddb3e0345a8133a’

  29 juillet 2013, par Michael Niedermayer

  Merge commit ’4f03a77e52596cbe9ec179666ddb3e0345a8133a’
  * commit ’4f03a77e52596cbe9ec179666ddb3e0345a8133a’ :
  
    oma : refactor seek function
  Merged-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavformat/omadec.c

• Android MediaRecorder setCaptureRate() and video playback speed

  7 novembre 2013, par spitzanator

  I've got a MediaRecorder recording video, and I'm very confused by the effect of setCaptureRate().

  Specifically, I prepare my MediaRecorder as follows :

  mMediaRecorder = new MediaRecorder();
  
  mCamera.stopPreview();
  
  mCamera.unlock();
  
  mMediaRecorder.setCamera(mCamera);
  
  mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
  
  mMediaRecorder.setProfile(CamcorderProfile.QUALITY_TIME_LAPSE_480P);
  
  mMediaRecorder.setCaptureRate(30f);
  
  mMediaRecorder.setOrientationHint(270);
  
  mMediaRecorder.setOutputFile(...);
  
  mMediaRecorder.setPreviewDisplay(...);
  
  mMediaRecorder.prepare();

  I record for five seconds (with a CountDownTimer, but that's irrelevant), and this is the file that gets generated :

  $ ffmpeg -i ~/CaptureRate30fps.mp4 
  
  ...
  
  Seems stream 0 codec frame rate differs from container frame rate: 180000.00 (180000/1) -> 30.00 (30/1)
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/home/mspitz/CaptureRate30fps.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 0
  
      compatible_brands: isom3gp4
  
      creation_time   : 2013-06-04 00:52:00
  
    Duration: 00:00:02.59, start: 0.000000, bitrate: 5238 kb/s
  
      Stream #0.0(eng): Video: h264 (Baseline), yuv420p, 720x480, 5235 kb/s, PAR 65536:65536 DAR 3:2, 30 fps, 30 tbr, 90k tbn, 180k tbc
  
      Metadata:
  
        creation_time   : 2013-06-04 00:52:00

  Note that the Duration is just about 3 seconds. The video also plays much faster, as if it were 5 seconds of video crammed into 3.

  Now, if I record by preparing my mediaRecorder exactly as above, but subtracting the setCaptureRate(30f) line, I get a file like this :

  $ ffmpeg -i ~/NoSetCaptureRate.mp4 
  
  ...
  
  Seems stream 0 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 '/home/mspitz/NoSetCaptureRate.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 0
  
      compatible_brands: isom3gp4
  
      creation_time   : 2013-06-04 00:50:41
  
    Duration: 00:00:04.87, start: 0.000000, bitrate: 2803 kb/s
  
      Stream #0.0(eng): Video: h264 (Baseline), yuv420p, 720x480, 2801 kb/s, PAR 65536:65536 DAR 3:2, 16.01 fps, 90k tbr, 90k tbn, 180k tbc
  
      Metadata:
  
        creation_time   : 2013-06-04 00:50:41

  Note that the Duration is as expected, about 5 seconds. The video also plays at a normal speed.

  I'm using setCaptureRate(30f) because 30 frames per second is the value of my CamcorderProfile's videoFrameRate. On my Galaxy Nexus S2 (4.2.1), omitting setCaptureRate() is fine, but when I tested on a Galaxy Nexus S3 (4.1.1), omitting setCaptureRate() results in the ever-helpful "start failed -22" error when I called mMediaRecorder.start().

  So, what am I missing ? I thought that the capture rate and the video frame rate were independent, but it's clear that they're not. Is there a way to determine programmatically what I need to set the capture rate at in order to determine that my video plays back at 1x speed ?

• audio frame multi-threaded decoding

  3 juin 2013, par Paul B Mahol

  audio frame multi-threaded decoding
  Signed-off-by : Paul B Mahol <onemda@gmail.com>
  

  • [DH] libavcodec/options_table.h
  • [DH] libavcodec/pthread.c
  • [DH] libavcodec/utils.c
  • [DH] libavformat/utils.c