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• ffmpeg audio stream retiming for infinite input

  26 février 2020, par Aeon

  I have a ffmpeg process that reads input data from stdout infinitely.
  Its input data are mkv (matroska) containers (sent to stdin by another process), each container contains 4 audio streams (without any video) - 3 ACC streams and 1 FLAC stream. The output of this process is dash muxer.

  ffmpeg -hide_banner -re -fflags +getpts -avoid_negative_ts make_non_negative -stream_loop -1 -f matroska -i pipe: -map 0 -c:a copy -strict -2 -f dash -use_timeline 1 -use_template 1 -seg_duration 5 -dash_segment_type mp4 manifest.mpd

  The problem occurs after the first muxing of obtained mkv file. When it’s time to mux the next one from pipe, I get following messages :

  [matroska,webm @ 000001d3050bba40] Found unknown-length element with ID 0x18538067 at pos. 0x54c766 for which no syntax for parsing is available.
  
  [matroska,webm @ 000001d3050bba40] Seek to desired resync point failed. Seeking to earliest point available instead.
  
  [dash @ 000001ac98349080] Non-monotonous DTS in output stream 0:0; previous: 881714, current: 51200; changing to 881715. This may result in incorrect timestamps in the output file.
  
  [dash @ 000001ac98349080] Non-monotonous DTS in output stream 0:1; previous: 881714, current: 51200; changing to 881715. This may result in incorrect timestamps in the output file.
  
  [dash @ 000001ac98349080] Non-monotonous DTS in output stream 0:2; previous: 881714, current: 51200; changing to 881715. This may result in incorrect timestamps in the output file.
  
  [dash @ 000001ac98349080] Non-monotonous DTS in output stream 0:3; previous: 884005, current: 51200; changing to 884006. This may result in incorrect timestamps in the output file.
  
  [dash @ 000001ac98349080] Non-monotonous DTS in output stream 0:3; previous: 884006, current: 51244; changing to 884007. This may result in incorrect timestamps in the output file.
  
  [dash @ 000001ac98349080] Non-monotonous DTS in output stream 0:3; previous: 884007, current: 51244; changing to 884008. This may result in incorrect timestamps in the output file.
  
  [dash @ 000001ac98349080] Non-monotonous DTS in output stream 0:3; previous: 884008, current: 51288; changing to 884009. This may result in incorrect timestamps in the output file.
  
  [dash @ 000001ac98349080] Non-monotonous DTS in output stream 0:3; previous: 884009, current: 51288; changing to 884010. This may result in incorrect timestamps in the output file.
  
  [dash @ 000001ac98349080] Non-monotonous DTS in output stream 0:3; previous: 884010, current: 51332; changing to 884011. This may result in incorrect timestamps in the output file.
  
  [dash @ 000001ac98349080] Non-monotonous DTS in output stream 0:3; previous: 884011, current: 51332; changing to 884012. This may resul
  
  ...

  and dash muxer simply stops generating new segments. I do understand that it’s an issue with timestamps, but I don’t know how to fix that.

  I’ve tried to use -fflags +getpts - no success.
  use_wallclock_as_timestamps 1 solves the "Non-monotonous DTS..." issue, but brings in a bunch of issues with playback, like freezing, breaking, etc., so the playback becomes completely unlistenable.
  Something strange also happens to the SegmentTemplate node of the manifest - its timescale attribute is set to 44100, although there should be 1000000 (-frag_duration 1 is ignored in this case)

  Question : I’m asking for your help in re-timing, i.e. generating the correct timestamps for dash muxing for each new incoming file in the pipe.

• How to make file .mpd for adaptive streaming supported on iOS device

  3 août 2020, par thxbox

  I would like to do DASH Adaptive Streaming in Ubuntu server. I used ffmpeg and MP4Box to convert video to .mpd file.

  


  Below is command that I use for convert and to generate a file

  


  ffmpeg -i myvideo.mp4 \
-vcodec libx264 \
-profile:v main -level 3.1 \
-preset medium \
-crf 23 \
-x264-params ref=4 \
-acodec copy \
-movflags +faststart myvideo-output.mp4


  


  MP4Box -dash 4000 \
-rap -bs-switching no 
-profile live \ 
-out myvideo-output.mpd \
-segment-name my_video_segment_ myvideo-output.mp4#audio myvideo-output.mp4#video


  


  in browser side, I implemented dash.js to video player.
the problem is it works on Chrome, Firefox and Safari on Desktop/iPad but it not works on some all iPhone.

  


  How to solve it ?

  


• How to split a 1 hour video .mp4 file into 5 seconds segments for Media Source Extension API

  15 avril 2018, par Harpreet Singh

  I’m designing a web media player with the Media Source Extension API. I really like the process of how dash.js distributes the media by having the original media split into number of small files and be played in the web. I have visited the source storage of the bbb_30fps at https://dash.akamaized.net/akamai/bbb_30fps. And I looked at the 720p video quality directory at https://dash.akamaized.net/akamai/bbb_30fps/bbb_30fps_1280x720_4000k and the audio directory at https://dash.akamaized.net/akamai/bbb_30fps/bbb_a64k. I saw that the original 10 min video has been split into small segments of 720p quality excluding the audio with the file type of .m4v and small segments of the audio excluding the video with the file type of m4a.

  I want to have my 1 hour .mp4 video split into 720p quality with separate segments of duration 5 seconds excluding the audio and with the file type of .m4v. I also want to split the audio into separate segments of 5 seconds excluding the video with the file type of .m4a. If someone can help me please comment below. Thanks

  So far I have visited http://www.instructables.com/id/Making-Your-Own-Simple-DASH-MPEG-Server-Windows-10/ but it want not able to help me with my needs. And I have tried number of other methods with MP4Box but I can’t get the result I want.