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• Programmatically creating mpd stream using Python

  3 février 2021, par mifol68042

  I have a live feed using RTSP from an IP camera that is captured using OpenCV in my python code. I capture every frame run some object detection on it and then need to show this in my angular front end.

  


  Initially I had thought to create an RTMP stream in my code and then use that in angular app but then realised that RTMP support is EOL on browsers. Now the alternative to this is that I am planning to create a stream using MPEG Dash. When researching about this, found this link to create a manifest mpd file however the examples there have no mention of the frames or video file. On researching more, I realised we could do something like this :

  


  ffmpeg -i $INPUT.mp4 \
-map 0:v:0 -map 0:a:0 -map 0:v:0 -map 0:a:0 \
-b:v:0 250k -filter:v:0 "scale=-2:240" -profile:v:0 baseline \ 
-b:v:1 750k -filter:v:1 "scale=-2:480" -profile:v:1 main \    
-use_timeline 1 -use_template 1 -window_size 5 \
-adaptation_sets "id=0,streams=v id=1,streams=a" -f dash $OUTPUT.mpd


  


  This is from command line but how can I achieve this programmatically ??? Also how do I keep updating the mp4 to get a live stream ??

  


  In short, I want to understand how to create live feed using frames via MPEG Dash.

  


• Optimizing Adaptive Streaming with FFMPEG

  25 octobre 2018, par Ramesh Navi

  I am working on a video on demand website, I am using laravel 5.7, FFMPEG and DASH player from (dashif.org). Got some questions.

  Extracting audio like :

  ffmpeg -i original.mp4 -vn -acodec libvorbis -ab 128k -dash 1 my_audio.webm

  Converting video like :

  ffmpeg -i original.mp4 -c:v libvpx-vp9 -keyint_min 150 \
  
  -g 150 -tile-columns 4 -frame-parallel 1  -f webm -dash 1 \
  
  -an -vf scale=160:190 -b:v 250k -dash 1 video_160x90_250k.webm \
  
  -an -vf scale=320:180 -b:v 500k -dash 1 video_320x180_500k.webm \
  
  -an -vf scale=640:360 -b:v 750k -dash 1 video_640x360_750k.webm \
  
  -an -vf scale=1280:720 -b:v 1500k -dash 1 video_1280x720_1500k.webm

  Creating manifest like :

  ffmpeg \
  
  -f webm_dash_manifest -i video_160x90_250k.webm \
  
  -f webm_dash_manifest -i video_320x180_500k.webm \
  
  -f webm_dash_manifest -i video_640x360_750k.webm \
  
  -f webm_dash_manifest -i video_1280x720_1500k.webm \
  
  -f webm_dash_manifest -i my_audio.webm \
  
  -c copy \
  
  -map 0 -map 1 -map 2 -map 3 -map 4 \
  
  -f webm_dash_manifest \
  
  -adaptation_sets "id=0,streams=0,1,2,3 id=1,streams=4" \
  
  my_video_manifest.mpd

  Now the problems :

  1. Video conversion takes a lot of time on the latest i5 8gb
     think-pad running Ubuntu 18. 4minute mp4 took more than 30minute. 10minute, 720p MP4 took forever, had to kill the process. Is
     that normal ? Any idea to optimize ?
  2. Need to find out original
     video’s dimension so that I can avoid dimension conversion more than
     the original. ffprob looks fine in command but produces too much of
     information than required, is there any simple function ?
  3. Converted webm file is bigger in size than original mp4, original
     mp4 of 720p was 33MB, but 640p webm is 76MB. Is that normal or
     something wrong ?

  Any suggestions to optimize the process are welcome.

• play video using ffplay remotely

  3 juin 2014, par Pavan K

  I am able to play videos with ffplay on the terminal of the computer using

  ffplay video.mp4

  But if I ssh into the computer via a different computer and call the command on the ssh terminal I get the following error.

  Could not initialize SDL - Unable to open a console terminal

  How can I invoke the video on the screen remotely ?