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• CMTimeGetSeconds doesn't get the right video duration

  26 février 2015, par JLCastillo

  some users don’t get the right duration of videos they capture with their own device. The funny thing is others do actually see it right, using the same device models and OS version. Anyway, we observed it in a iPhone 5c 7.1.2 and an iPhone 5s 8.1.3.

  This code works for most users, but not all :

  ALAssetRepresentation *representation = [mediaObject.asset defaultRepresentation];
  
  NSURL *url = [representation url];
  
  NSDictionary *options = @{ AVURLAssetPreferPreciseDurationAndTimingKey : @YES };
  
  AVAsset *avAsset = [AVURLAsset URLAssetWithURL:url options:options];
  
  videoDurationTime = CMTimeGetSeconds(avAsset.duration);

  I asked them to send the input videos, and this is the output from "ffmpeg -i"

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'bug_duration1.MOV':
  
    Metadata:
  
      major_brand     : qt
  
      minor_version   : 0
  
      compatible_brands: qt
  
      creation_time   : 2015-02-23 08:30:01
  
      encoder         : 8.1.3
  
      encoder-eng     : 8.1.3
  
      date            : 2015-02-23T16:30:01+0800
  
      date-eng        : 2015-02-23T16:30:01+0800
  
      model           : iPhone 5s
  
      model-eng       : iPhone 5s
  
      make            : Apple
  
      make-eng        : Apple
  
    Duration: 00:00:03.67, start: 0.000000, bitrate: 16793 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080, 16719 kb/s, 29.99 fps, 29.97 tbr, 600 tbn, 1200 tbc (default)
  
      Metadata:
  
        creation_time   : 2015-02-23 08:30:01
  
        handler_name    : Core Media Data Handler
  
        encoder         : H.264
  
      Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 61 kb/s (default)
  
      Metadata:
  
        creation_time   : 2015-02-23 08:30:01
  
        handler_name    : Core Media Data Handler

  The video is detected with a duration of several minutes. Did anybody face this problem before ?

  Thanks in advance.

• error : No accelerated colorspace conversion found., vision_opencv stack in ros,avi video file processing

  4 août 2017, par rajat

  When i try to run some custom node to process some .avi video i have this error : i guess this error is related to opencv , i have tried all the sloutions , even recompiled vision_opencv with FFMPEG flag on , and urgraded ffmped with —enable-shared —enable-gpl —enable-swscale , but still no luck .

  [swscaler @ 0x842fa20]No accelerated colorspace conversion found.
  
  [swscaler @ 0x848aa80]No accelerated colorspace conversion found.
  
  Last message repeated 10 times 
  
  [swscaler @ 0x8497c80]No accelerated colorspace conversion found.  
  
  [swscaler @ 0x848aa80]No accelerated colorspace conversion found. 
  
  Last message repeated 10 times 
  
  [swscaler @ 0x8497c60]No accelerated colorspace conversion found. 
  
  [swscaler @ 0x848aa80]No accelerated colorspace conversion found.
  
  Last message repeated 10 times 
  
  [swscaler @ 0x8495730]No accelerated colorspace conversion found. 
  
  [swscaler @ 0x848aa80]No accelerated colorspace conversion found.
  
  Last message repeated 10 times 
  
  [swscaler @ 0x8492ae0]No accelerated colorspace conversion found.
  
  [swscaler @ 0x848aa80]No accelerated colorspace conversion found. 
  
  Last message repeated 10 times 
  
  [swscaler @ 0x8492d00]No accelerated colorspace conversion found.
  
  [swscaler @ 0x848aa80]No accelerated colorspace conversion found. 
  
  Last message repeated 10 times
  
  [swscaler @ 0x8491c70]No accelerated colorspace conversion found. 
  
  [swscaler @ 0x848aa80]No accelerated colorspace conversion found

  i can’t proceed with my project , until i sort this out and i already have wasted more than 10hrs on this problem , so if you guys think of any solution i would be glad to try it out .

• ffmpeg / video processing : make video repeat itself without duplicating content ?

  31 mars 2022, par RocketNuts

  Suppose I have a video file that is 20 MB in size and lasts 30 seconds.

  


  I want to create a new video file that basically consists of the existing video, repeated 10 times. So the new video should last 300 seconds (5 minutes) and contain the same content every 30 seconds.

  


  I could of course append this video to itself 10 times, resulting in a file of approximately 200 MB. But this seems very redundant, since obviously the same content is in there tenfold. I was hoping for a somewhat more intelligent approach, where the same 30 seconds of video is somehow 'referenced' 10 times over.

  


  Do common encoders or container formats (say h.264 in a .mp4 or .mkv container) support this ? And by any chance is there a way to pull this off with ffmpeg ?