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• Video Conversion ? with ffmpeg

  10 août 2017, par Lee Brindley

  I’m building a react native app for both Android and IOS, the back-end API is written with NodeJS.

  Users may upload video from their phones, once uploaded the user and their friends will be able to view the video - so the videos need to be stored in a format which is playable on both Android & IOS.

  My question relates to the conversion of video, uploaded by the user. I have developed a similar app a couple of years ago, I used the repo node-fluent-ffmpeg which provides a nice API to interact with ffmpeg.

  In the previous project (which was a web app), I converted the uploaded videos into two files, one .mp4 and one .webm - if a user uploaded a mp4, then I would skip the mp4 step, likewise if they uploaded a .webm.

  This was kind of slow. Now i’ve come across the same requirement years later, after some research I think I was wrong to convert the videos in the last project.

  I’ve read that I can simply use ffmpeg to change the container format of the videos, which is a much faster process than converting them from scratch.

  The video conversion code I used last time went something along the lines of :

  var convertVideo = function (source, format, output, success, failure, progress) {
  
  
  
      var converter = ffmpeg(source);
  
  
  
      var audioCodec = "libvorbis";
  
  
  
      if (format.indexOf("mp4") != -1) {
  
          audioCodec = "aac";
  
      }
  
  
  
      converter.format(format)
  
          .withVideoBitrate(1024)
  
          .withAudioCodec(audioCodec)
  
          .on('end', success)
  
          .on('progress', progress)
  
          .on('error', failure);
  
  
  
      converter.save(output);
  
  };

  Usage :

  Convert to mp4 :

  convertVideo("PATH_TO_VIDEO", "mp4", "foo.mp4", () => {console.log("success");});

  Convert to webm :

  convertVideo("PATH_TO_VIDEO", "webm", "foo.webm", () => {console.log("success");});

  Can anyone point out a code smell here regarding performance of this operation ? Is this code doing a lot more than it should to achieve cross platform compatibility between IOS and Android ?

  Might be worth mentioning that support for older OS versions is not such a big deal in this project.

• Video conversion with ffmpeg to target Android and iOS mobile devices

  17 novembre 2017, par Lee Brindley

  I’m building a react native app for both Android and IOS, the back-end API is written with NodeJS.

  Users may upload video from their phones, once uploaded the user and their friends will be able to view the video - so the videos need to be stored in a format which is playable on both Android & IOS.

  My question relates to the conversion of video, uploaded by the user. I developed a similar app a couple of years ago ; I used the repo node-fluent-ffmpeg which provides a nice API to interact with FFmpeg.

  In the previous project (which was a web app), I converted the uploaded videos into two files, one .mp4 and one .webm - if a user uploaded an mp4, then I would skip the mp4 step, likewise if they uploaded a .webm.

  This was kind of slow. Now I’ve come across the same requirement years later, after some research I think I was wrong to convert the videos to the last project.

  I’ve read that I can simply use FFmpeg to change the container format of the videos, which is a much faster process than converting them from scratch.

  The video conversion code I used last time went something along the lines of :

  var convertVideo = function (source, format, output, success, failure, progress) {
  
  
  
      var converter = ffmpeg(source);
  
  
  
      var audioCodec = "libvorbis";
  
  
  
      if (format.indexOf("mp4") != -1) {
  
          audioCodec = "aac";
  
      }
  
  
  
      converter.format(format)
  
          .withVideoBitrate(1024)
  
          .withAudioCodec(audioCodec)
  
          .on('end', success)
  
          .on('progress', progress)
  
          .on('error', failure);
  
  
  
      converter.save(output);
  
  };

  Usage :

  Convert to mp4 :

  convertVideo("PATH_TO_VIDEO", "mp4", "foo.mp4", () => {console.log("success");});

  Convert to webm :

  convertVideo("PATH_TO_VIDEO", "webm", "foo.webm", () => {console.log("success");});

  Can anyone point out a code smell here regarding the performance of this operation ? Is this code doing a lot more than it should achieve cross-platform compatibility between IOS and Android ?

  Might be worth mentioning that support for older OS versions is not such a big deal in this project.

• ffmpeg progress is freezing frames when scene change

  19 août 2017, par Karol

  I’m capturing data from IP camera with RTSP protocol with ffmpeg with command :

  ffmpeg -rtsp_transport tcp -progress /media/kamip/stats.txt -i rtsp://192.168.1.220:554/live/h264/ch0 
  
  -c:v copy -c:a copy -strict 1 -map 0 -f segment -strftime 1 
  
  -segment_time 1800 /media/kamip/cam_%d_%m_%Y_%H_%M_%S.mkv

  I’m using this for 5 cameras. One is different type and it is in different location.
  Because ffmpeg does not support reconnect I’m writing status to /media/kamip/stats.txt file. In another script I’m parsing this output and every 30 seconds I’m checking if frame number changed, if yes - it is ok, if not, I’m restarting above command.

  The problem is only in the night. When is quite dark and suddenly lights on, for example when car is parking, the /media/kamip/stats.txt is showing the same frame number, so my script is recognizing this as a lost connection (video freeze)

  I tried "-strict 1" option and I think it is better (one false alarm per day instead of 10 per day), so I think this may be related to ffmpeg, not camera/video source, especially because the video is fine even frame number reported by ffmpeg is still the same. Also VLC does not have this kind of problem (but I cannot use it currently for this camera)

  I found that ffmpeg has build-in scene change detector, but it should works only when encoding video (I’m using "copy" option for audio and video) ?

  I’m thinking about different way of analyzing the video capturing, but this "-progress" in ffmpeg should works fine - and it is working fine for other cameras for few years).

  I also do not see any errors,
  when I encoded one cutted file with "-loglevel debug" I saw only information like below :

  [libx264 @ 0x25d77a0] scene cut at 174 Icost:2049115 Pcost:2006553 
  
  ratio:0.0208 bias:0.1387 gop:54 (imb:3186 pmb:168)

  ffmpeg in latest version

  ffmpeg version 3.3.3-1ubuntu1~16.04.york0 Copyright (c) 2000-2017 the FFmpeg developers
built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.4) 20160609

  any help will be appreciated