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• flutter_ffmpeg - how to access the path of the output ?

  7 août 2021, par Richardd

  I need to merge (concatenate) two audio files in a Flutter app.

  



  I am trying to use Flutter_ffmpeg package .

  



  https://pub.dev/packages/flutter_ffmpeg


  



  Ffmpeg is powerful tool for audio and video.

  



  flutter_cache_manager package to store the files that came from https

  



  https://pub.dev/packages/flutter_cache_manager


  



  And path provided to deal with the paths

  



  https://pub.dev/packages/path_provider


  



  For the part of caching I already made some successful tests,

  



  But, I need your help to understand how can I use ffmpeg package.
  
According to the readme I need to do something like

  



  import 'package:flutter_ffmpeg/flutter_ffmpeg.dart';

final FlutterFFmpeg _flutterFFmpeg = new FlutterFFmpeg(); 
var fileCached1 = await DefaultCacheManager().getSingleFile(url1);
var fileCached2 = await DefaultCacheManager().getSingleFile(url2);
var arguments = ["-i", "concat:fileCached1.wav|fileCached2.wav", "-c copy", "output.way"];
_flutterFFmpeg.executeWithArguments(arguments ).then((rc) => print("FFmpeg process exited with rc $rc"));


  



  How can I have access to the output.wav to play ? How can I use the path_provider ?

  



  I really need you help. :)
There is little information about flutter_ffmpeg. This question might be useful for someone else to.

  



  Thanks in advance,
Ricardo

  


• Is it possible using FFMPEG to replace one ".ts" file in a HLS ts file collection with another ".ts" file ?

  27 juillet 2019, par Vadim

  There is a video, actually an HLS stream (sequence of TS files)
  I would like to take out one TS chunk and replace it with another.
  Another chunk will be encoded using same FFMPEG encoding settings.

  In case you wonder why i need this :
  There is a five hours HLS stream. One of TS has a wrong title on the video. I need to change that TS without re-encoding the whole HLS stream.

  Currently i tried :

  1. Take TS and convet it using FFMPEG into mp4
  2. Edit mp4 video (change title) and save as new mp4
  3. Convert new mp4 into new TS (using FFMPEG, same settings as was used for original video)
  4. Replace original TS with the new TS.

  But it doesn’t work, player shows loading in progress icon. (in the network console i see that this new TS is loaded normally, with status 200)

  As soon as i replace new TS with original one, player plays it normally.

  Both TS files start with I-frame, both have audio. There’s only a slight difference in the sequence of P and B frames.

  old new
  
  I   I
  
  P   P
  
  B   B
  
  B   B
  
  P   P
  
  B   B
  
  B   B
  
  B   B
  
  P   P
  
  B   B
  
  B   P
  
  B   B
  
  P   B
  
  P   B
  
  B   P

  How can i get new TS chunk working in original TS sequence ?

  Update :

  As per szatmary advice (below) i tried to include "-copyts" flag during all ts>mp4>ts conversions. Also tried "-copytb" flag with all 3 options -1, 0, and 1. However result still the same - player doesn’t play HLS TS sequence (m3u8) with new TS chunk.

  Adding "#EXT-X-DISCONTINUITY" tag after replaced TS in the M3U8 list, doesn’t fix the situation.

  Without "#EXT-X-DISCONTINUITY" tag, player gives error :

  VIDEOJS: ERROR: (CODE:4 MEDIA_ERR_SRC_NOT_SUPPORTED) There appears to be a playback issue.
  
  
  
  code: 4
  
  message: "There appears to be a playback issue."
  
  
  
  __proto__:
  
  MEDIA_ERR_ABORTED: 1
  
  MEDIA_ERR_CUSTOM: 0
  
  MEDIA_ERR_DECODE: 3
  
  MEDIA_ERR_ENCRYPTED: 5
  
  MEDIA_ERR_NETWORK: 2
  
  MEDIA_ERR_SRC_NOT_SUPPORTED: 4
  
  code: 0
  
  message: ""
  
  status: null

  With "#EXT-X-DISCONTINUITY" tag, player gives error :

  VIDEOJS: ERROR: (CODE:3 MEDIA_ERR_DECODE) There appears to be a playback issue.
  
  
  
  code: 3
  
  message: "error"
  
  
  
  __proto__:
  
  MEDIA_ERR_ABORTED: 1
  
  MEDIA_ERR_CUSTOM: 0
  
  MEDIA_ERR_DECODE: 3
  
  MEDIA_ERR_ENCRYPTED: 5
  
  MEDIA_ERR_NETWORK: 2
  
  MEDIA_ERR_SRC_NOT_SUPPORTED: 4
  
  code: 0
  
  message: ""
  
  status: null

  Both TS files (old one and new one) have video and audio streams.

  Looks like something else should be done. I think solution will be similar to ad insertion.

• Revision faff6ed0fb : Skip duplicate block encoding in the rd loop This speed feature allows the enco

  9 juillet 2013, par Jingning Han

  Changed Paths :
   Modify /vp9/encoder/vp9_block.h

  
   Modify /vp9/encoder/vp9_encodeframe.c

  
   Modify /vp9/encoder/vp9_encodeintra.c

  
   Modify /vp9/encoder/vp9_encodemb.c

  
   Modify /vp9/encoder/vp9_onyx_if.c

  
   Modify /vp9/encoder/vp9_onyx_int.h

  
   Modify /vp9/encoder/vp9_rdopt.c

  
   Modify /vp9/encoder/vp9_rdopt.h

  
  
  Skip duplicate block encoding in the rd loop

  This speed feature allows the encoder to largely remove the spatial
  dependency between blocks inside a 64x64 superblock, thereby removing
  the need to repeatedly encode superblocks per partition type in the
  rate-distortion optimization loop.

  A major challenge lies in the intra modes tested in the rate-distortion
  optimization loop. The subsequent blocks do not have access to the
  reconstructed boundary pixels without the intermediate coding steps.
  This was resolved by using the original pixels for intra prediction
  in the rd loop, followed by an appropriately designed distortion
  modeling on the quantization parameters. Experiments also suggested
  that the performance impact is more discernible at lower bit-rate/psnr
  settings. Hence a quantizer dependent threshold is applied to deactivate
  skip of block coding.

  For bus_cif at 2000 kbps,
  speed 0 : runtime 269854ms -> 237774ms (12% speed-up) at 0.05dB
  performance loss.

  speed 1 : runtime 65312ms -> 61536ms, (7% speed-up) at 0.04dB
  performance loss.

  This operation is currently turned on in settings of speed 1.

  Change-Id : Ib689741dfff8dd38365d8c1b92860a3e176f56ec