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• Segmenting video into different parts and unique rendering on each part then concat afterwards

  2 mars 2016, par goudarziha

  I currently have a very poorly performing application that splits up a video, renders it and the concats all rendered videos on android using ffmpeg

  So I am running into issues with segmenting a video up into 5 parts at each different intervals/durations, rendering each video segment uniquely slowing up/speeding up and then finally concat all the segments back into one final video.

  Currently I am doing each part separately -

  Segmenting -
  example for one segment
  -y -i pathIn -ss 0.0 -t 2.0 -vcodec copy -acodec copy -an pathOut

  Rendering - example slowing down/speeding up
  
   y -i path -filter:v setpts=2.0*PTS pathOut

  Concat -
  
   f concat -i input1.mp4 -i input2.mp4 -i input3.mp4 -i input4.mp4 -i input5.mp4 -c copy output.mp4

  Right now I am running different separate thread for each editing of video, so 3, segment, rendering and concat.

  I am trying to get this all done on one command ffmpeg line if at all possible, if not just the segmenting and rendering of the videos and kick of the concat cmd line later.

  I am trying to emulate something similar to this https://trac.ffmpeg.org/wiki/Creating%20multiple%20outputs

• How to replace a snippet in a video without reencoding the whole video

  3 novembre 2022, par Simon Streicher

  I am trying to edit and replace a section of a video without reencoding the whole video.
Here are the steps I think I need to take :

  


  1. Find keyframes

  


  input :

  


  ffprobe -v error -select_streams v:0 -skip_frame nokey -show_entries frame=pkt_pts_time -of csv=p=0 'example.mkv'


  


  output :

  


  0.000000
1.001000
11.011000
13.430000
20.812000
30.822000
40.832000
50.842000
⋮


  


  2. Export relevant section

  


  For example, export the snippet 40.832000 → 50.842000.

  


  3. Edit and reencode

  


  After editing that section, I need to reencode it to the original codecs for compatibility with the surrounding video. For example, this is the original codecs :

  


  Stream #0:0: Video: hevc (Main 10), yuv420p10le(tv, bt2020nc/bt2020/smpte2084), 3840x1600 [SAR 1:1 DAR 12:5], 23.98 fps, 23.98 tbr, 1k tbn, 23.98 tbc (default)


  


  4. Inject edit back into the video stream

  


  Finally, I need to use FFmpeg somehow to retain everything from the original file (audio, subtitles, chapters, etc.) and to construct a new video stream (for example, Stream #0:0) that is exactly 0 → 40.832000 of the original, the whole edited section, and 50.842000 → end of the original section.

  


  My main questions are :

  


  

  • A. How do I trim the video stream in 2. without reencoding ?

  


  • B. Assuming that the edited video's resolution will remain the same, what is the command for FFmpeg to encode my edit to the codecs in 3. (and would the video be concatenable with the original video) ?

  


  • C. How should I go about glueing the sections together ? Should I simply trim Stream #0:0 into sections v1 = 0 → 40.832 and v2 = 50.842 → end and then concatenate a new stream as new = v1 + edited + v2 ?

  


  • D. How do I replace Stream #0:0 with new ?

  


  


  And probably the most important question : are my assumptions correct and can this be achieved ?

  


• ffmpeg converted mp4 video format is not playing on html5 video player

  15 août 2017, par alina

  i have converted a video via ffmpeg to mp4 but its playing on desktop pc player like Vlc but not on html5 player or wordpress player.

  Iam using this command while conversion :

  ffmpeg." -i ".$video_to_convert." -i watermark.png -filter_complex 'overlay=10:main_h-overlay_h-10' -c:v libx264 -crf 17 -preset slow -c:a libfaac -b:a 192k -ac 2 -b:a ".$quality." -acodec libmp3lame -ab 126000 -ar ".$audio." -ac 2 -s ".$size." ".$converted_vids.$name.".".$new_format."

  where :

  .$video_to_convert. = input.mp4

  .$converted_vids.$name. = output.mp4

  is there any syntax problem ??????????????????