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• Live stream multi-bitrate video

  2 septembre 2017, par Rishabh

  Preface

  I have read this two part tutorial (Part-1 and Part-2) by Steamroot on MPEG-DASH, and below is my understanding (please correct me if I am wrong) :

  • The video needs to be encoded into multiple bit-rates using FFmpeg.
  • The encoded videos need to be transcoded (dashified) using MP4Box.
  • The dashified videos can be served using a web server.

  Problem

  I intend to live-stream an event and I need help to understand the following :

  1. Can I club the FFmpeg and MP4Box commands into a single step ? Maybe through a wrapper program so that I do not have to run them separately ? Is there any other or better solution ?
  2. How do I send the dashified content to the web server ? FTP ? Would any vanilla web server do ?
  3. Lastly, a friend had hinted that I could also use GStreamer to achieve my objective. But, I could not find any good resource on the internet for the same. So, where (and how) does GStreamer fit in the above process ?

• libdash mpd parser integration with custom player

  19 novembre 2016, par Raj

  I have written a multimedia player using ffmpeg and qt-framework. And currently I support local file playback and progressive download playback in my player. Now I want to add support for mpeg-dash vod stream playback. I thought of using libdash opensource dash library. But after so much of googling I couldn’t find any API or developer documentation regarding the same.

  Also another issue is libdash has integrated network module. But I want only mpd parser to be integrated and I have my own network module for downloading. I couln’t find any doxygen and usage documentation for libdash.

  I need help in these :

  1. Can you anyone point me to any developer documentation available for
     libdash ?
  2. Is there any alternative library for libdash ?

• How to not add AdaptationSet for audio in cmd file if audio stream is not present in input video file

  15 juin 2019, par Saurabh

  I am using ffmpeg-dash to create mpd files. I am using following command to generate the same :

  ffmpeg -i input/video.mov \
  
          -map 0:v:0 -map 0:v:0 -map 0:v:0 -map 0:a\?:0 \
  
          -b:v:0 350k -c:v:0 libx264 -filter:v:0 "scale=320:-1" \
  
          -b:v:1 1000k -c:v:1 libx264 -filter:v:1 "scale=640:-1" \
  
          -b:v:2 3000k -c:v:2 libx264 -filter:v:2 "scale=1280:-1" \
  
          -use_timeline 1 -use_template 1 -window_size 6  -adaptation_sets "id=0,streams=v id=1,streams=a"  \
  
          -seg_duration 2 -threads 16 -hls_playlist true -f dash output/ffmpeg/output.mpd

  This works with video which has audio streams, but for the case there is no audio stream in the video file, I get empty entry for audio in mpd files like following, which is not valid and fails while playing in Exo Player in Android.

  <adaptationset contenttype="audio" segmentalignment="true" bitstreamswitching="true">
  
  </adaptationset>

  I tried adding ? in option adaptation_sets like : id=0,streams=v id=1,streams=a?, however that also adds above line.

  One solution is to run different commands for different videos by first checking whether there is audio stream or not, but would be better if there is some option which add audio adaptationSet only if audio stream is present in the input file.