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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.

• How build ffmpeg optimized for iOS, using hardware decoding probably ?

  9 décembre 2013, par jAckOdE

  I make a FFMPEG-based player for ios. It works fine on simulator, but on real-device (iPhone 4) the frame rate is low and make my audio and video out of sync. the player works fine on iPhone 4s, so I guess it's just problem about device's computing power.

  So, is there anyway to build FFMPEG optimized for iOS device (armv7, arvm7s arch) ? or is there anyway to utilize ios device hardware to decode video stream ?

  My video stream is encode in H264/AAC.

• ffmpeg convert mp4 video for phones

  23 avril 2015, par Ar Megatox

  I need to make a video which will play on iPhone and Android but the problem is when I click play on the phone it needs minimum 7 seconds to start.

  So maybe I need to fix something in this code to make the video play on phones (maybe another format is needed) :

  ffmpeg -i VIDEO -c:v libx264 -s 640x480 -strict experimental -c:a aac VIDEO.MP4 

  There must be something to make the video play faster without a delay on start.

  I tried a FLV file and it worked fine on Android but the iPhone can’t play it.