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• Compressing videos from a smartphone

  9 novembre 2016, par fejesjoco

  I have a Nexus 6p with the stock camera. It’s set to record at 1080p, 30fps. Here’s a 5 second sample (11 MB).

  Videos from this phone come out at about 17 Mbps on average. I tried to compress it with ffmpeg with -c:v libx264 -crf 23 -preset veryslow, the result comes out at about 5.5 MB, which is about 9 Mbps.

  I think this bitrate is a bit too much. When I look at torrent file listings, I can see high quality videos at 3 GB in size on average, and if such a movie is 90 minutes long on average, that is about 4-5 Mbps which sounds okay.

  I’m wondering, why the big difference ? I can notice that my video is noisy/grainy (which is expected from a phone), and that might reduce compressibility. I tried a few ffmpeg filters, like hqdn3d and atadenoise, but the noise mostly remained (maybe I didn’t play with it enough). Then I figured, the video is also shaky (which is also expected), and that might reduce compressibility too (and even makes temporal noise filtering less effective). I tried to stabilize it with the deshake filter, but that didn’t help either.

  I know I could just limit the bandwidth to whatever I like, but there must be a reason why ffmpeg thinks it needs a high bandwidth to maintain a certain quality, and a lower bandwidth would just decrease the quality.

  Why do these videos have such a high bitrate ? What’s the best way to compress them more while keeping or even increasing their quality ?

• Android ffmpeg video cut

  20 octobre 2016, par Raupp

  I´m trying to edit some videos in my Android app using FFmpeg, but I´m facing some problems when I tried to take just a part of the video.

  I´m using this ffmpeg compilation/lib https://github.com/WritingMinds/ffmpeg-android-java

  I tried to use this command to trim/cut the video

  "-y -i input.mp4 -ss 00:00:01.00 -t 00:00:15.000 -c copy output.mp4"

  But with some videos I´m getting a black screen or the video just freezes. The sound works fine in all my tests.

  With this command

  "-y -i input.mp4 -ss 00:00:01.000 -t 00:00:15.000 -async 1 output.mp4"

  Everything works fine in all my tests (video/sound) but takes too much time to generate the output file, this 15s file takes more than 2 minutes to be generated.

  I tried other variations of these commands, but I always get problems with the video stream (with black screen or freezing) or takes too much time to generate the output (the user can only select 15s of the videos to send to my server)

  Thanks by the help !

  EDIT :

  this is the part of the code that is trimming the video

  String[] cmd = new String[]{"-y","-i",input,"-ss","00:00:05.000","-vcodec","copy",
  
              "-acodec","copy","-t","00:00:15.00","-strict","-2",output };
  
  
  
      final FFmpeg ffmpeg = FFmpeg.getInstance(this);
  
      try {
  
          ffmpeg.execute(cmd, new FFmpegExecuteResponseHandler() {
  
              @Override
  
              public void onSuccess(String message) {
  
                  Log.i("VideoEditActivity", "Success " + message);
  
                  is_video_generated_ = true;
  
              }
  
  
  
              @Override
  
              public void onProgress(String message) {
  
                  Log.i("VideoEditActivity", "Progress updated " + message);
  
              }
  
  
  
              @Override
  
              public void onFailure(String message) {
  
                  Log.e("VideoEditActivity", "ERROR! " + message);
  
              }
  
  
  
              @Override
  
              public void onStart() {
  
                  progress_dialog_.setMessage(getString(R.string.str_video_generating));
  
                  progress_dialog_.show();
  
              }
  
  
  
              @Override
  
              public void onFinish() {
  
                  Log.i("VideoEditActivity", "Finished");
  
                  progress_dialog_.hide();
  
  
  
                  Intent intent = new Intent(getApplicationContext(), VideoPlayActivity.class);
  
                  intent.putExtra("media", edited_video_path_);
  
                  startActivity(intent);
  
              }
  
          });
  
      } catch (FFmpegCommandAlreadyRunningException e) {
  
          e.printStackTrace();
  
      }

  This is the original file : [https://drive.google.com/file/d/0BzqJL_nNetbRYmxvcTljanJwR00/view?usp=sharing][1]

  And this the output : 0BzqJL_nNetbReENjRGMtVXQ5VHM/view ?usp=sharing (stack overflow does not allow me to add more than 2 links)

• ffmpeg - whatsapp : video format not supported

  31 décembre 2016, par Santhosh Yedidi

  I have two videos (.mp4) files. One uploads to whatsapp and another does not.

  using ffmpeg i checked their properties :

  a) Properties of video which uploads :

    Duration: 00:00:56.45, start: 0.148000, bitrate: 1404 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1080x1080, 1359 kb/s, 23.98 fps, 23.98 tbr, 90k tbn, 47.95 tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(eng): Audio: aac (HE-AACv2) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 47 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
  At least one output file must be specified

  b) video which does not upload to whatsapp (because its says format not supported)

    Duration: 00:00:56.10, start: 0.000000, bitrate: 543 kb/s
  
      Stream #0:0: Video: h264 (High) (H264 / 0x34363248), yuv420p, 1080x1080 [SAR 1:1 DAR 1:1], 464 kb/s, 23.98 fps, 23.98 tbr, 23.98 tbn, 47.95 tbc
  
      Stream #0:1: Audio: aac (LC) ([255][0][0][0] / 0x00FF), 48000 Hz, stereo, fltp, 56 kb/s

  The difference in video I noticed :

  (avc1 / 0x31637661) vs (H264 / 0x34363248)

  1359 kb/s vs 464 kb/s

  90k tbn vs 23.98 tbn

  What can be the reason

  Also the second video is not being played in Android.

  The link for the video is

  https://drive.google.com/open?id=0B4UM6vTHw4pyMExQQ1lxZGp0N2c