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• How to detect a surge of activity in a video ?

  22 mars 2019, par Alain Collins

  I’d like to automatically detect a surge of activity in a video, e.g. basketball jump shot, hockey face-off, sprinters starting, etc., preferably using ffmpeg.

  In these instances, there’s some motion as the players assume their positions, followed by a pause as they wait for the ref to throw the ball or drop the puck, followed by a lot of motion as all players begin to react. It’s also typical that the camera will be still during this period and begin moving as the ball or puck changes position.

  I’ve tried using the ’select’ filter select='gt(scene,0.4)', but that seems to be more concerned with scene changes (i.e., more dramatic changes) even with low thresholds.

  I also tried exporting the scene information and examining it manually, but couldn’t find a clear pattern that correlated with motion in the video.

  UPDATE : I ran a mestimate on the video. Processing took a long time, but there was definitely a change in activity before and at point of interest. Is there a way to export this information to a file, or otherwise detect the amount of motion seen my mestimate ?

• How to set specific minimal bitrate of video with light_compressor package in Flutter ?

  21 juin 2023, par Giant Brain

  I tried using flutter's light_compressor package to compress a video I shot with my phone or downloaded from YouTube.

  


  I refer to the article below.
https://morioh.com/p/ac6f0d2c176b
In this article, the minimum bit rate can be set and the default value is 2mbps.

  


  However, in the sample code, only the flag isMinBitrateCheckEnabled exists, and there is no parameter to set a specific bit rate.

  


  How do I compress the video to my desired bitrate ?

  


  Below is a part of the sample code.

  


  import 'package:light_compressor/light_compressor.dart';


final LightCompressor _lightCompressor = LightCompressor();
final dynamic response = await _lightCompressor.compressVideo(
  path: _sourcePath,
  destinationPath: _destinationPath,
  videoQuality: VideoQuality.medium,
  isMinBitrateCheckEnabled: false,
  frameRate: 24 /* or ignore it */);


  


• MP4 Videos on website embed with html5 does not play on iOS

  31 août 2012, par Sidner

  So I have a couple of videos on my website that I shot using the iPhone 4 and then converted to mp4, webm and ogg, so that I can use them with html5. Thing is, the video does not play at all on the 4 iOS devices that I tested and neither on Chrome for Android.

  The Chrome issue could be because some of the mp4 are actually m4v files, but still after encoding with handbrake a video to the iphone 4 presset and in mp4 format, it still does not play.

  What happens, you ask ? Well, it shows the play button crossed out with a diagonal bar, the debug console on Safari does not show any message untill I try to access the video directly. Then it says : QuickTime Movie could not be played.

  What can I do ? I have been trying to encode with ffmpeg, have tried a handful of different solutions, some even found here on stackoverlow, but to no avail. The videos do get shorter, both in display size and MBs, but nothing works to fix the issue at hand.

  I've been trying to get this corrected for a couple of weeks now. Any help and/or suggestions are welcome.

  Thank you.

  By the way, all the videos are on a registred users section of the website, but I have one for debugin on the main page, so feel free to test.

  https://sidnerwebsite.sytes.net