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• How to create video and audio files for the Media Source Extension API ?

  5 décembre 2018, par Aman

  I have created a video player from the Media Source Extension API. I have split the video and audio from the original.mp4 (1 minute duration). I have split the video and audio into small 5 second files (12 files in total). I’m getting each one of them and playing them together. But the video stops playing at around 45-47 seconds. I cannot understand to why the video is stopping/buffering. I cannot understand whether the problem is in the javascript code or the video files ?

  I have uploaded all the resources here (https://drive.google.com/file/d/1NHc_yNRU0tvaU18aohLy74Js3y7UHD4N/view?usp=sharing). And written the commands I used to construct my video and audio files below. I have also noticed that this problem only occurs with Google Chrome and works perfectly and smoothly on Microsoft Edge. Thanks

  Making the Media files:

  Extracting video from original.mp4: MP4Box -single 1 original.mp4

  Extracting audio from original.mp4: MP4Box -single 2 original.mp4

  Splitting the video and audio into 5 second parts: ffmpeg -ss starting-time -to end-time -i (video.mp4 OR audio.mp4) (video_part.mp4 OR audio_part.mp4)

  Fragmenting all the video and audio parts: MP4Box -dash 1000 -rap -frag-rap(video_part.mp4 OR audio_part.mp4)

  Then using the fragmented video and audio files to be played via the Media Source Extension API video player. e.g. (video_part_dashinit.mp4 OR audio_part_dashinit.mp4)

• Encoding and segmenting HD video for DASH [closed]

  13 mars 2013, par user2163937

  I am trying to encode video for implementing DASH, for encoding I am using this command line...

  ffmpeg -i sample.ts -f mpegts -acodec libfaac -ar 44100 -ab 64k -s 480x270
  
  -vcodec libx264 -b 500k -r 25 -flags +loop -partitions
  
  +parti4x4+partp8x8+partb8x8 -subq 5 -refs 6  -keyint_min 10 -i_qfactor 0.71 
  
  -maxrateD 500k -bufsize 500k -rc_eq 'blurCplx^(1-qComp)' -qmin 10 -qmax 51
  
  -qdiff 4 -level 30 -aspect 16:9 -g 30 -async 2 out.ts

  For segmentation I use this command line

  ffmpeg -i out.ts -c copy -map 0 -f ssegment -segment_time 4 -segment_list
  
  out.list seg%d.ts   

  And I use the various resolutions and parameters according to the table given in this link.

  Given resolutions and parameters are working fine for me, I can able to get smooth transition among various resolutions. But problem arises when I try to use HD resolution i.e 1280x720, there is a visible flicker when video switches from HD to other resolution or vice-versa. I cannot figure out the problem.

• ffmpeg scaled output resolution is off by 1px for non-standard inputs [duplicate]

  14 janvier 2023, par GROVER.

  I'm using the ffmpeg CLI to scale user-submitted videos :

  


  ffmpeg -i path/to/file -vf scale=1920:-2 -c:v libx264 -r 30 output.mp4


  


  The scaling works fine with standard video sizes, such as 1920×1080 and 720×480. However, once we start using videos that do not have conventional resolutions, the output begins to scale incorrectly.

  


  For example, a video that has a resolution of 3360×1882 will output to 1921×1076, when the expected resolution should theoretically be : 1920×1075.

  


  Now, obviously ffmpeg is attempting to account for that remaining .42857px on the height, but I'd prefer it just get cropped off instead (doesn't matter if it's from the top or bottom).

  


  How would I go about doing this safely for every video ?

  


  For bonus points, how do I make it swap scaling depending on if the height is greater than the width (and vice versa). For example, if the video has a ratio of 2:1, it scales using a height of 1080px instead of a width of 1920px.