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• HTML5 video after FFmpeg compress set currentTime behavior defferent in browsers

  5 novembre 2019, par Qyellow

  i have a mp4 video(oceans.mp4), and i use ffmpeg compress itffmpeg -i oceans.mp4 output.mp4(output.mp4).

  then i open the origin in the chrome and safari, in the console, i write :

  var video = document.querySelector('video')
  
  video.currentTime = 4.68

  the video locate the same frame(at least looks the same)

  but i open the output, it looks different !

  so i do many test :

  1. it might be the broswers difference ?
     may be not. the origin video looks totally the same
  2. it might be the some props of video ?
     i use ffprobe -show_streams -select_streams v:0  output.mp4to show and compare two videos, only has_b_frames(0 and 2) and bitrates are different

  3. it might be had_b_frames ?
     ffmpeg -i oceans.mp4 -bf 0 output.mp4
     then i use the command to set it to 0, but it do not work...(sad

  4. it might be the ffmpeg’s error !(i have no idea...)

     ffmpeg -i oceans.mp4 -vcodec copy -an output_file.mp4
     i use the command only get video but delete audio...the video is corrent

  so i have no idea why the video show different... please help me

• HTML5 video - frame accurate seeking on Android devices ?

  27 mai 2015, par GFoley83

  I’m working on an app that requires frame accurate seeking on video in the browser, across desktop and mobile devices (including packaged apps with Cordova).

  Desktop browsers work fine as do iOS devices (both as a packaged app and through Safari) but Android devices only seem to show key frames (aka intra frames or i-frames) in the video.

  I’ve setup a test page on jsfiddle to help demo my problem.

  The video has been encoded with ZenCoder. It has a frame rate of 23.976 and key frames every 250 frames. The video itself shows the current frame index so you can easily see that only the frames at 0, 250 and 500 frames are being displayed on Android devices, regardless of where you seek to.

  At this stage I’d be happy with a solution that works in Android browsers or as a packaged app with Cordova (I’ve also tried using the Crosswalk WebView but to no avail).

• Looking to play back non-encoded video upload then export gif from selection point via FFMPEG

  10 novembre 2019, par Christopher Neil

  We’ve been trying to crack this code all week, reaching out to everyone to see if you have any solutions ?

  1. We want the user to upload a video and in the next step he will select a small 5 second loop of the video which will be made as a gif.
  2. Old developer was able to do this by splicing the video at 10 seconds instead of 5 but not re-encoding it meant that it would sometimes be beyond 12 seconds and in some cases less than 7.
  3. We changed the code to force keyframes with re encoding so that it splices the video at exactly 5 seconds to show the loop.
  4. These slices are shown to the user using html5 video player.
  5. Upon selection of the loop that sliced video is converted to gif.

  Everything is working in the vice order. The issue is when the user uploads a large sized and length video this slicing and re-encoding takes forever and that cause the user to feel the site is not working properly.

  What we want is very simple :

  1. Show 5 second portion of the video on loop.
  2. If user wants to select another loop he/she clicks the next button and is taken to the next 5 second loop which would be either at 25% of the video or some other
  3. On selection of that portion it converts it into gif.