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• 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.

• How can I capture low resolution video on Android reliably across a range of devices ?

  8 décembre 2017, par MisterMat

  Hello Android video experts :)

  I am developing an Android application which allows the user to capture video and upload it to a remote server (it’s more involved than that but the rest of the app is not important). Because of the upload requirement, it is important that the video is of a reasonable size, so not super high resolution. Let’s say a max of 680x480 or 10Mb/minute. This is no problem on Apple devices.

  I have had what can only be described as a complete nightmare trying to capture video at a reasonably low bitrate reliably across a range of Android devices.

  As I understand it there are two ways of capturing video on Android :

  1) Using the Media Recorder/Camera API

  2) Using an Intent to open the cameras video capture application

  Option 1) gives the most flexibility and allows us to easily change the capture resolution. However the Android Camera API is NOT reliable across a range of devices, and I have very good information (including from someone who liaised with Google on this issue) that if you capture video using this API then it will crash on a good 50% of the devices out there. There is a reason that Zoom Camera FX uses an Intent for video capture. Zoom Camera (different app) seems to use Media Recorder, but has lots of bad reviews for video crashing or not working.

  Option 2) works well across a range of devices, as it uses the in built application on the device. The trouble is you have no control whatsoever on the resolution, there is a quality hint on the Intent but the camera app will normally ignore this. My Samsung Galaxy S3 records video by default at about 2Mb/s. This is way too high resolution. The built in application can of course change the resolution, but this relies on action by the user which is difficult to control.

  I understand that I could use a library such as ffmpeg to change the resolution of the video after capture. However this requires me to compile the library for Android, and also I have been informed that in order to legally use the decode/encode codecs on the device you have to pay license fees that amount to about $1 per copy of the app. Since this app will be free to use, this is not an option.

  So that’s where I’m at. I’ve searched long and high for answers, but I can’t figure out how to capture low resolution video reliably using Android.

  Any help very much appreciated !

  Matthew

• FFmpeg get list of devices thought python

  2 octobre 2020, par kali_xyyali

  Wassup.

  
I have shell command.

  


  ffmpeg -list_devices true -f dshow -i dummy -hide_banner


  


  When i run that command i get output data(see text bellow)

  


  [dshow @ 00000281450fbdc0] DirectShow video devices (some may be both video and audio devices)
[dshow @ 00000281450fbdc0]  "HD WebCam"
[dshow @ 00000281450fbdc0]     Alternative name "@device_pnp_\\?\usb#vid_0408&pid_a060&mi_00#6&391c16c1&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global"
[dshow @ 00000281450fbdc0] DirectShow audio devices

[dshow @ 00000281450fbdc0]  "Microphone (Realtek High Definition Audio)"
[dshow @ 00000281450fbdc0]     Alternative name "@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\wave_{4727F33A-DE04-4706-8312-03696FACC791}"
[dshow @ 00000281450fbdc0]  "Stereo mix (Realtek High Definition Audio)"
[dshow @ 00000281450fbdc0]     Alternative name "@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\wave_{534A8FBC-6C02-4384-B51C-D0363BB7F8FD}"
[dshow @ 00000281450fbdc0]  "Microphone (Avsoft Virtual Audio Device)"
[dshow @ 00000281450fbdc0]     Alternative name "@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\wave_{5CE20B48-361E-4B96-B113-B3E02BA448EC}"
dummy: Immediate exit requested


  


  I have to get list of all audio devices.
And i don't want to parse that string, i will be hard.
How can i get list of all audio devices using ffmpeg-python module ?
Thank u.