Hello,
Bravo, congratulations for your fantastic tool. Before that, I managed to download separate 1080p video & audio files from You tuben but always failed to remux them correctly (I tried ffmpeg, mp4creator, mp4box). I guess your app does download both HD tracks (audio & video) separately as well, before remuxing them in a mp4 container, in a transparent way for the user. Well done.
BUT : Although I did succeed to download a 1h50' HD MP4 (1080p) concert from youtube, I notice that the picture and sound are not exactly in sync, especially at the end of the video (getting worse. So I guess it is particularily problematic for long videos like full concerts).
When downloading separately both tracks (before I knew your app, using KeepVid applet), I noticed that the audio file and the video file don't have exactly the same duration.
What could we do inside your app to ensure a perfect synchronization ?
All the best, keep up the good work.