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• 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.

• drawtext video transition is not smooth

  7 juin 2020, par Sterpu Mihai

  Edit : it seems that youtube displays the 00:05 transition smoothly ; however, my local VLC doesn't so I think this must be a VLC issue of some kind.

  



  Take a look at this video : https://youtu.be/47JJnrH_LyM

  



  It's created from a bigger video and it's composed of 3 parts :

  



  part 1: 00:00 - 00:05 original.mp4
part 2: 00:05 - 00:10 original_with_caption.mp4
part 3: 00:10 - 00:15 original.mp4


  



  The caption snippet was created using the following command :

  



  ffmpeg -ss 00:05 -t 5 -i original.MP4 -vf drawtext="fontfile=C\\:/Windows/Fonts/arial.ttf:fontsize=100:fontcolor=white:x=(w-text_w)/2:y=(h-th-100):text='some random text here'" original_with_caption.MP4


  



  The cuts from the original video were made with the following commands :

  



  ffmpeg -y -i D:\temp\0706\caption\original.MP4 -ss 0 -t 5 -c copy D:\temp\0706\caption\ws\original_split_0_5.MP4
ffmpeg -y -i D:\temp\0706\caption\original.MP4 -ss 10 -t 5 -c copy D:\temp\0706\caption\ws\original_split_10_15.MP4


  



  Finally, all 3 have been merged together by creating a concat.txt file containing the following :

  



  file D:\\temp\\0706\\caption\\ws\\original_split_0_5.MP4
file D:\\temp\\0706\\caption\\original_with_caption.MP4
file D:\\temp\\0706\\caption\\ws\\original_split_10_15.MP4


  



  and then executing the command :

  



  ffmpeg -f concat -safe 0 -i D:\temp\0706\caption\ws\concat.txt -c copy D:\temp\0706\caption\ws\output.MP4


  



  The problem I'm facing is that the transition from 00:05 is not smooth whereas the one from 00:10 is.
What do I need to adapt so the transition is smooth ?

  


• How to use ffmpeg filter to remove a frame every 12 seconds [closed]

  28 juin 2024, par YOURSELF BEST

  I want to delete 1 frame every 12 frames of the video. The original video has a frame rate of 30, so after deleting it, it becomes 28. How should I write this operation using ffmpeg ?

  


  I used the following command, but there is a problem, the new video generated will be shorter than the original video

  


  ffmpeg -y -r 28 -vsync 0 -i demo.mp4 -vf "select='mod(n+4,12)',setpts='N/28/TB'" "demo_2.mp4"

  


  Please help me how should I do it, thanks