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• ios video after trimming then play on non ios device audio/video out of sync

  31 août 2015, par gavinHe

  trimming video,then I send the video trimmed to android device and play,I find audio/video out of sync, the audio is several seconds behind the video. but the video can play normal on iOS device.
  1.I trim video with codes like this :

   - (IBAction)showTrimmedVideo:(UIButton *)sender
  
  {
  
  [self deleteTmpFile];
  
  
  
  NSURL *videoFileUrl = [NSURL fileURLWithPath:self.originalVideoPath];
  
  
  
  AVAsset *anAsset = [[AVURLAsset alloc] initWithURL:videoFileUrl options:nil];
  
  NSArray *compatiblePresets = [AVAssetExportSession exportPresetsCompatibleWithAsset:anAsset];
  
  if ([compatiblePresets containsObject:AVAssetExportPresetMediumQuality]) {
  
  
  
      self.exportSession = [[AVAssetExportSession alloc]
  
                            initWithAsset:anAsset presetName:AVAssetExportPresetHighestQuality];
  
      // Implementation continues.
  
  
  
      NSURL *furl = [NSURL fileURLWithPath:self.tmpVideoPath];
  
  
  
      self.exportSession.outputURL = furl;
  
      self.exportSession.outputFileType = AVFileTypeMPEG4;
  
  
  
      CMTime start = CMTimeMakeWithSeconds(self.startTime, anAsset.duration.timescale);
  
      CMTime duration = CMTimeMakeWithSeconds(self.stopTime-self.startTime, anAsset.duration.timescale);
  
      CMTimeRange range = CMTimeRangeMake(start, duration);
  
      self.exportSession.timeRange = range;
  
  
  
      self.trimBtn.hidden = YES;
  
      self.myActivityIndicator.hidden = NO;
  
      [self.myActivityIndicator startAnimating];
  
      [self.exportSession exportAsynchronouslyWithCompletionHandler:^{
  
  
  
          switch ([self.exportSession status]) {
  
              case AVAssetExportSessionStatusFailed:
  
                  NSLog(@"Export failed: %@", [[self.exportSession error] localizedDescription]);
  
                  break;
  
              case AVAssetExportSessionStatusCancelled:
  
                  NSLog(@"Export canceled");
  
                  break;
  
              default:
  
                  NSLog(@"NONE");
  
                  dispatch_async(dispatch_get_main_queue(), ^{
  
                      [self.myActivityIndicator stopAnimating];
  
                      self.myActivityIndicator.hidden = YES;
  
                      self.trimBtn.hidden = NO;
  
                      [self playMovie:self.tmpVideoPath];
  
                  });
  
                  break;
  
          }
  
      }];
  
  }
  
  }

  2.I send the video trimmed to server,then android device get video from server,but they find audio/video out of sync,at first I consider of server do something wrong,so I just send video to android device with USB,the error still exist.

  3.so I analyze the trimmed video by ffmpeg tools :
  ffmpeg -i trimVideo.mp4
  then I find trimVideo.mp4 start is a negative number.
  here is what ffmpeg print :

  Metadata :
  major_brand : qt
  minor_version : 0
  compatible_brands : qt
  creation_time : 2015-08-29 12:22:13
  encoder : Lavf56.15.102
  Duration : 00:02:21.77, start : -4.692568, bitrate : 359 kb/s
  Stream #0:0(und) : Audio : aac (LC) (mp4a / 0x6134706D), 24000 Hz, stereo, fltp, 69 kb/s (default)
  Metadata :
  creation_time : 2015-08-29 12:22:13
  handler_name : Core Media Data Handler
  Stream #0:1(und) : Video : h264 (High) (avc1 / 0x31637661), yuv420p, 512x288 [SAR 1:1 DAR 16:9], 277 kb/s, 15.16 fps, 15.17 tbr, 12136 tbn, 30.34 tbc (default)
  Metadata :
  creation_time : 2015-08-29 12:22:13
  handler_name : Core Media Data Handler
  encoder : ’avc1’

  I have been puzzled by this bug for several days, I am sorry of my bad english and I really need your help,thanks.

• How to embed subtitles into an mp4 file using gstreamer

  27 août 2021, par Stephen

  My Goal

  


  I'm trying to embed subtitles into an mp4 file using the mp4mux gstreamer element.

  


  What I've tried

  


  The pipeline I would like to use is :

  


  GST_DEBUG=3 gst-launch-1.0 filesrc location=sample-nosub-avc.mp4 ! qtdemux ! queue ! video/x-h264 ! mp4mux name=mux reserved-moov-update-period=1000 ! filesink location=output.mp4 filesrc location=english.srt ! subparse ! queue ! text/x-raw,format=utf8 ! mux.subtitle_0


  


  It just demuxes a sample mp4 file for the h.264 stream and then muxes it together with an srt subtitle file.

  


  The error I get is :

  


  Setting pipeline to PAUSED ...&#xA;0:00:00.009958915 1324869 0x5624a8c7a0a0 WARN                 basesrc gstbasesrc.c:3600:gst_base_src_start_complete:<filesrc0> pad not activated yet&#xA;Pipeline is PREROLLING ...&#xA;0:00:00.010128080 1324869 0x5624a8c53de0 WARN                 basesrc gstbasesrc.c:3072:gst_base_src_loop:<filesrc1> error: Internal data stream error.&#xA;0:00:00.010129102 1324869 0x5624a8c53e40 WARN                 qtdemux qtdemux_types.c:239:qtdemux_type_get: unknown QuickTime node type pasp&#xA;0:00:00.010140810 1324869 0x5624a8c53de0 WARN                 basesrc gstbasesrc.c:3072:gst_base_src_loop:<filesrc1> error: streaming stopped, reason not-negotiated (-4)&#xA;0:00:00.010172990 1324869 0x5624a8c53e40 WARN                 qtdemux qtdemux.c:3237:qtdemux_parse_trex:<qtdemux0> failed to find fragment defaults for stream 1&#xA;ERROR: from element /GstPipeline:pipeline0/GstFileSrc:filesrc1: Internal data stream error.&#xA;Additional debug info:&#xA;gstbasesrc.c(3072): gst_base_src_loop (): /GstPipeline:pipeline0/GstFileSrc:filesrc1:&#xA;streaming stopped, reason not-negotiated (-4)&#xA;ERROR: pipeline doesn&#x27;t want to preroll.&#xA;Setting pipeline to NULL ...&#xA;Freeing pipeline ...&#xA;</qtdemux0></filesrc1></filesrc1></filesrc0>

  


  My Thoughts

  


  I believe the issue is not related to the above warning but rather mp4mux's incompatibility with srt subtitles.

  


  The reason I belive this is because, other debug logs hint at it, but also stealing the subititles from another mp4 file and muxing it back together does work.

  


  gst-launch-1.0  filesrc location=sample-nosub-avc.mp4 ! qtdemux ! mp4mux name=mux ! filesink location=output.mp4 filesrc location=sample-with-subs.mp4 ! qtdemux name=demux demux.subtitle_1 ! text/x-raw,format=utf8 ! queue ! mux.subtitle_0


  


  A major catch 22 I am having is that mp4 files don't typically support srt subtitles, but gstreamer's subparse element doesn't support parsing mp4 subtitle formats (tx3g, ttxt, etc.) so I'm not sure how I'm meant to put it all together.

  


  I'm very sorry for the lengthy question but I've tried many things so it was difficult to condense it. Any hints or help is appreciated. Thank you.

  


• How to encode multi audio streams with different options at the same time using ffmpeg

  20 mars 2012, par Luca Borrione

  I'm trying to encode a dvd using ffmpeg.

  $ffmpeg -i VTS_01_1.VOB
  
  Input #0, mpeg, from 'VTS_01_1.VOB':
  
  Duration: 00:38:06.52, start: 0.287267, bitrate: 3756 kb/s
  
  Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x576 [SAR 64:45 DAR 16:9], 9800 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
  
  Stream #0:1[0x80]: Audio: ac3, 48000 Hz, 5.1(side), s16, 384 kb/s
  
  Stream #0:2[0x81]: Audio: ac3, 48000 Hz, 5.1(side), s16, 384 kb/s
  
  Stream #0:3[0x82]: Audio: ac3, 48000 Hz, 5.1(side), s16, 384 kb/s
  
  Stream #0:4[0x83]: Audio: ac3, 48000 Hz, mono, s16, 96 kb/s
  
  Stream #0:5[0x28]: Subtitle: dvd_subtitle
  
  Stream #0:6[0x29]: Subtitle: dvd_subtitle
  
  Stream #0:7[0x23]: Subtitle: dvd_subtitle
  
  Stream #0:8[0x24]: Subtitle: dvd_subtitle
  
  Stream #0:9[0x26]: Subtitle: dvd_subtitle
  
  Stream #0:10[0x27]: Subtitle: dvd_subtitle

  From the above streams I'm interested in keeping two audio streams : number 1 and 4.
  As you can see the number 4 is already 96kbps so I tried to execute a command which could treat the two streams in a different way :

  cat VTS_01_1.VOB | nice ffmpeg -i - -s 640x368 -vcodec libtheora -r 25 -b:v 1200k -an -metadata title="My Title" -pass 1 -passlogfile "/media/data/outputlog" -f ogg -y /dev/null
  
  
  
  cat VTS_01_1.VOB | nice ffmpeg -i - -map 0:0 -s 640x368 -vcodec libtheora -r 25 -b:v 1200k -async 1 -metadata title="My Title" -map 0:1 -acodec libvorbis -ac 6 -ar 48000 -b:a 192k -metadata title="english" -map 0:4 -acodec libvorbis -ac 2 -ar 48000 -b:a 96k -metadata title="commented" -pass 2 -passlogfile "/media/data/outputlog" "/media/data/output.ogv"

  What I would like to obtain is :

  Input #0, ogg, from 'output.ogv':
  
  Duration: 00:38:07.20, start: 0.000000, bitrate: 1360 kb/s
  
  Stream #0:0: Video: theora, yuv420p, 640x368 [SAR 46:45 DAR 16:9], 25 fps, 25 tbr, 25 tbn, 25 tbc
  
  Stream #0:1: Audio: vorbis, 48000 Hz, stereo, s16, 192 kb/s
  
  Stream #0:2: Audio: vorbis, 48000 Hz, stereo, s16, 96 kb/s

  Instead with the above command I obtain :

  Input #0, ogg, from 'output.ogv':
  
  Duration: 00:38:07.20, start: 0.000000, bitrate: 1360 kb/s
  
  Stream #0:0: Video: theora, yuv420p, 640x368 [SAR 46:45 DAR 16:9], 25 fps, 25 tbr, 25 tbn, 25 tbc
  
  Stream #0:1: Audio: vorbis, 48000 Hz, stereo, s16, 96 kb/s
  
  Stream #0:2: Audio: vorbis, 48000 Hz, stereo, s16, 96 kb/s

  So how can I specify different params for multiple audio streams ?

  BTW : I'm on lubuntu oneiric with the latest ffmpeg from git

  ffmpeg version git-2012-03-05-1007a80 Copyright (c) 2000-2012 the FFmpeg developers
  
  built on Mar  5 2012 09:40:09 with gcc 4.6.1
  
  configuration: --enable-gpl --enable-libfaac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libx264 --enable-nonfree --enable-version3 --enable-x11grab --enable-libxvid --enable-libvpx
  
  libavutil      51. 41.100 / 51. 41.100
  
  libavcodec     54.  8.100 / 54.  8.100
  
  libavformat    54.  2.100 / 54.  2.100
  
  libavdevice    53.  4.100 / 53.  4.100
  
  libavfilter     2. 63.100 /  2. 63.100
  
  libswscale      2.  1.100 /  2.  1.100
  
  libswresample   0.  7.100 /  0.  7.100
  
  libpostproc    52.  0.100 / 52.  0.100

  Therefore the newaudio option is no more recognized