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• 1 movie to 14 part video / 1 Subtitle [closed]

  10 avril 2020, par Tayfun Erbilen

  I just cut my one long movie to 14 piece with ffmpeg.

  



  And now, I don't know how to show subtitle.

  



  Subtitle was for full version, but now I have 14 pieces and I don't know how to fit subtitle to these parts. By the way, I want to show on web. I'm using jwplayer for videos, but still I didn't figure out subtitle issue.

  



  Is anyone suggestion ?

  


• created .webm from .mp4 with ffmpeg is async due to start_time>0 in video stream

  25 février 2015, par chuckice

  since a couple of days i’m trying to figure out a solution for syncronization issue, using ffmpeg as a transcoding application.

  i create a 1-fps .webm-preview of my .mp4-Video with the following ffmpeg command line :

  ffmpeg -i input.mp4 -vcodec libvpx -b:v 500k -ss 0 -qmin 10 -qmax 42 -maxrate 500k -bufsize 1000k -vf scale=768:576 -an -r 1 -g 0 -y output.webm

  after my .webm-format is transcoded, i realize that f.e. position 00:00:10.000 in both videos does not have the same image.

  after reading parts of the ffmpeg documentation, i found the parameter -vsync

  -vsync parameter

  0, passthrough : Each frame is passed with its timestamp from the demuxer to the muxer.

  1, cfr : Frames will be duplicated and dropped to achieve exactly the requested constant frame rate.

  2, vfr : Frames are passed through with their timestamp or dropped so as to prevent 2 frames from having the same timestamp.

  drop : As passthrough but destroys all timestamps, making the muxer generate fresh timestamps based on frame-rate.

  -1, auto : Chooses between 1 and 2 depending on muxer capabilities. This is the default method.

  As i’m kind of new to ffmpeg, i’d like to ask for help to spare my troubles.

  Anybody ?

  Update : Digging deeper i found out that my mp4-Source had an offset in the beginning.

  So i should solve this problem first.

  Documenting my work, i found out, that the video-Stream in my .mp4-Format has the following offset, defined as start_time.

  ffprobe -v quiet -show_streams -print_format json -i archiv.mp4 
  
  {
  
      "streams": [
  
          {
  
              "index": 0,
  
              "codec_name": "h264",
  
              "codec_long_name": "H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10",
  
              "profile": "High",
  
              "codec_type": "video",
  
              "codec_time_base": "1/100",
  
              "codec_tag_string": "avc1",
  
              [..]
  
              "start_time": "1.080000",
  
              [..]
  
      ]

  Is there a way, resetting this start_time of the stream by ffmpeg ? Right now, im using the following command-line :

  ffmpeg -i input.ts -vf yadif -c:v libx264 -crf 24 -c:a libmp3lame -y -strict -2 -b:v 4000k -copyts -start_at_zero archiv.mp4

• Is it possible to merge two or more videos in real-time like this ?

  25 février 2015, par Marko

  Is it possible to play video online that’s made of two or more video files ?

  Since my original post wasn’t clear enough, here’s expanded explanation and question.

  My site is hosted on Linux/Apache/PHP server. I have video files in FLV/F4V format. I can also convert them to other available formats if necessary. All videos have same aspect ratio and other parameters.

  What I want is to build (or use if exist) online video player that plays video composed of multiple video files concatenated together in real-time, i.e. when user clicks to see a video.

  For example, visitor comes to my site and sees video titled "Welcome" available to play. When he/she clicks to play that video, I take video files "Opening.f4v", "Welcome.f4v" and "Ending.f4v" and join/merge/concatenate them one after another to create one continuous video on the fly.

  Resulting video looks like one video, with no visual clues, lags or even smallest observable delay between video parts. Basically what is done is some form of on-the-fly editing or pre-editing, and user sees the result. This resulting video is not saved on the server, it’s just composed and played that way real-time.

  Also, if possible, user shouldn’t be made to wait for this merging to be over before he/she sees resulting video, but to be able to get first part of the video playing immediately, while merging is done simultaneously.

  Is this possible with flash/actionscript, ffmpeg, html5 or some other online technology ? I don’t need explanation how it’s possible, just a nod that it’s possible and some links to further investigate.

  Also, if one option is to use flash, what are alternatives for making this work when site is visited from iphone/ipad ?