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• AVPlayer currentTime not match with the displayed frame after many seeking. (HLS Stream)

  26 août 2022, par D.Bence

  I have a m3u8 file which i want to use with HLS.
link to m3u8 file

  


  My problem is that when i seek many times, the currentTime not match with the displayed frame. I experience that, the more seeking there is more difference. (it's like a constant +offset)

  


  Our use case is very timing sensitive, we need to stop the videos at specific positions. For this we use the following code :

  


  [_player addBoundaryTimeObserverForTimes:times
      queue:dispatch_get_main_queue()
      usingBlock:^{
            weakSelf.player.rate = 0.0;
            // The time is correct here, but the displayed frame is not sync with this time
            CMTimeShow(weakSelf.player.currentTime);
      }
]   


  


  I read that AVURLAssetPreferPreciseDurationAndTimingKey can help, but the currentTime still wrong.

  


  NSDictionary<nsstring> *options = @{AVURLAssetPreferPreciseDurationAndTimingKey:@YES};&#xA;AVURLAsset *urlAsset = [AVURLAsset URLAssetWithURL:url options:options];&#xA;AVPlayerItem *item = [AVPlayerItem playerItemWithAsset:urlAsset];&#xA;</nsstring>

  


  I also read that there is a problem with the m3u8 itself. (for example wrong GOP size.)

  


  What is the reason for the incorrect currentTime, and how can i fix this ?

  


  ffprobe m3u8 :

  


  ffprobe https://mrkresz-content-bucket.s3.eu-central-1.amazonaws.com/applicationData/extended-path-videos/4b0046fd-0be7-4a07-bc7c-c1a0069116b1/released/50816bc9-6118-4dd1-a90e-fb72652bb06f-final-from-anonymized.m3u8
ffprobe version 5.1 Copyright (c) 2007-2022 the FFmpeg developers
  built with Apple clang version 13.1.6 (clang-1316.0.21.2.5)
  configuration: --prefix=/opt/homebrew/Cellar/ffmpeg/5.1 --enable-shared --enable-pthreads --enable-version3 --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libdav1d --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librist --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libspeex --enable-libsoxr --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox --enable-neon
  libavutil      57. 28.100 / 57. 28.100
  libavcodec     59. 37.100 / 59. 37.100
  libavformat    59. 27.100 / 59. 27.100
  libavdevice    59.  7.100 / 59.  7.100
  libavfilter     8. 44.100 /  8. 44.100
  libswscale      6.  7.100 /  6.  7.100
  libswresample   4.  7.100 /  4.  7.100
  libpostproc    56.  6.100 / 56.  6.100
[hls @ 0x152f04280] Skip ('#EXT-X-VERSION:3')
[hls @ 0x152f04280] Skip ('#EXT-X-INDEPENDENT-SEGMENTS')
[hls @ 0x152f04280] Opening 'https://mrkresz-content-bucket.s3.eu-central-1.amazonaws.com/applicationData/extended-path-videos/4b0046fd-0be7-4a07-bc7c-c1a0069116b1/released/50816bc9-6118-4dd1-a90e-fb72652bb06f-final-from-anonymized1080p_6000000bitrate.m3u8' for reading
[hls @ 0x152f04280] Skip ('#EXT-X-VERSION:3')
[https @ 0x154045000] Opening 'https://mrkresz-content-bucket.s3.eu-central-1.amazonaws.com/applicationData/extended-path-videos/4b0046fd-0be7-4a07-bc7c-c1a0069116b1/released/50816bc9-6118-4dd1-a90e-fb72652bb06f-final-from-anonymized1080p_15000000bitrate.m3u8' for reading
[hls @ 0x152f04280] Skip ('#EXT-X-VERSION:3')
[https @ 0x154045000] Opening 'https://mrkresz-content-bucket.s3.eu-central-1.amazonaws.com/applicationData/extended-path-videos/4b0046fd-0be7-4a07-bc7c-c1a0069116b1/released/50816bc9-6118-4dd1-a90e-fb72652bb06f-final-from-anonymized1520p_33000000bitrate.m3u8' for reading
[hls @ 0x152f04280] Skip ('#EXT-X-VERSION:3')
[hls @ 0x152f04280] Opening 'https://mrkresz-content-bucket.s3.eu-central-1.amazonaws.com/applicationData/extended-path-videos/4b0046fd-0be7-4a07-bc7c-c1a0069116b1/released/50816bc9-6118-4dd1-a90e-fb72652bb06f-final-from-anonymized1080p_6000000bitrate_00001.ts' for reading
[hls @ 0x152f04280] Opening 'https://mrkresz-content-bucket.s3.eu-central-1.amazonaws.com/applicationData/extended-path-videos/4b0046fd-0be7-4a07-bc7c-c1a0069116b1/released/50816bc9-6118-4dd1-a90e-fb72652bb06f-final-from-anonymized1080p_6000000bitrate_00002.ts' for reading
[hls @ 0x152f04280] Opening 'https://mrkresz-content-bucket.s3.eu-central-1.amazonaws.com/applicationData/extended-path-videos/4b0046fd-0be7-4a07-bc7c-c1a0069116b1/released/50816bc9-6118-4dd1-a90e-fb72652bb06f-final-from-anonymized1080p_15000000bitrate_00001.ts' for reading
[hls @ 0x152f04280] Opening 'https://mrkresz-content-bucket.s3.eu-central-1.amazonaws.com/applicationData/extended-path-videos/4b0046fd-0be7-4a07-bc7c-c1a0069116b1/released/50816bc9-6118-4dd1-a90e-fb72652bb06f-final-from-anonymized1080p_15000000bitrate_00002.ts' for reading
[hls @ 0x152f04280] Opening 'https://mrkresz-content-bucket.s3.eu-central-1.amazonaws.com/applicationData/extended-path-videos/4b0046fd-0be7-4a07-bc7c-c1a0069116b1/released/50816bc9-6118-4dd1-a90e-fb72652bb06f-final-from-anonymized1520p_33000000bitrate_00001.ts' for reading
[hls @ 0x152f04280] Opening 'https://mrkresz-content-bucket.s3.eu-central-1.amazonaws.com/applicationData/extended-path-videos/4b0046fd-0be7-4a07-bc7c-c1a0069116b1/released/50816bc9-6118-4dd1-a90e-fb72652bb06f-final-from-anonymized1520p_33000000bitrate_00002.ts' for reading
Input #0, hls, from 'https://mrkresz-content-bucket.s3.eu-central-1.amazonaws.com/applicationData/extended-path-videos/4b0046fd-0be7-4a07-bc7c-c1a0069116b1/released/50816bc9-6118-4dd1-a90e-fb72652bb06f-final-from-anonymized.m3u8':
  Duration: 00:49:43.00, start: 2.033367, bitrate: 0 kb/s
  Program 0
    Metadata:
      variant_bitrate : 8133826
  Stream #0:0: Video: h264 (Main) ([27][0][0][0] / 0x001B), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 29.97 fps, 29.97 tbr, 90k tbn
    Metadata:
      variant_bitrate : 8133826
  Program 1
    Metadata:
      variant_bitrate : 18870392
  Stream #0:1: Video: h264 (Main) ([27][0][0][0] / 0x001B), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 29.97 fps, 29.97 tbr, 90k tbn
    Metadata:
      variant_bitrate : 18870392
  Program 2
    Metadata:
      variant_bitrate : 40776144
  Stream #0:2: Video: h264 (Main) ([27][0][0][0] / 0x001B), yuv420p, 2704x1520 [SAR 1:1 DAR 169:95], 29.97 fps, 29.97 tbr, 90k tbn
    Metadata:
      variant_bitrate : 40776144


  


  ffprobe original mp4 :

  


  ffprobe https://mrkresz-content-bucket.s3.eu-central-1.amazonaws.com/applicationData/extended-path-videos/4b0046fd-0be7-4a07-bc7c-c1a0069116b1/finalized/50816bc9-6118-4dd1-a90e-fb72652bb06f-final-from-anonymized.mp4
ffprobe version 5.1 Copyright (c) 2007-2022 the FFmpeg developers
  built with Apple clang version 13.1.6 (clang-1316.0.21.2.5)
  configuration: --prefix=/opt/homebrew/Cellar/ffmpeg/5.1 --enable-shared --enable-pthreads --enable-version3 --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libdav1d --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librist --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libspeex --enable-libsoxr --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox --enable-neon
  libavutil      57. 28.100 / 57. 28.100
  libavcodec     59. 37.100 / 59. 37.100
  libavformat    59. 27.100 / 59. 27.100
  libavdevice    59.  7.100 / 59.  7.100
  libavfilter     8. 44.100 /  8. 44.100
  libswscale      6.  7.100 /  6.  7.100
  libswresample   4.  7.100 /  4.  7.100
  libpostproc    56.  6.100 / 56.  6.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'https://mrkresz-content-bucket.s3.eu-central-1.amazonaws.com/applicationData/extended-path-videos/4b0046fd-0be7-4a07-bc7c-c1a0069116b1/finalized/50816bc9-6118-4dd1-a90e-fb72652bb06f-final-from-anonymized.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.76.100
  Duration: 00:49:42.81, start: 0.000000, bitrate: 36142 kb/s
  Stream #0:0[0x1](und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(progressive), 2486x1398, 36138 kb/s, 29.97 fps, 29.97 tbr, 30k tbn (default)
    Metadata:
      handler_name    : VideoHandler
      vendor_id       : [0][0][0][0]


  


• How convert High bitrate mp3 to lower rate using ffmpeg in android

  23 mars 2018, par Android Team

  We want to convert 320kbps mp3 file to 128kbps mp3 so currently we are using below ffmpeg command but its not working.

  ffmpeg -i input.mp3 -codec:a libmp3lame -qscale:a 5 output.mp3

  Result :-the output bitrate same as input mp3.

  And we are following the FFmpeg Encoding guideline for that here is the link :- https://trac.ffmpeg.org/wiki/Encode/MP3

  so please suggest any solution.

• doc : delete viterbi.txt

  10 novembre 2013, par Timothy Gu

  doc : delete viterbi.txt
  The description has been moved to the FFmpeg wiki :
  
  https://trac.ffmpeg.org/wiki/ViterbiAlgorithm
  Signed-off-by : Timothy Gu <timothygu99@gmail.com>
  

  • [DH] doc/viterbi.txt