I have video and audio files of a movie.
the audio file is 10 seconds longer than the video file. When I merge files with "megui muxer", synchronization does not hold. I think I have to cut 10 seconds from the end of the audio file. How do i do that?
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Well, if you just cut 10 seconds at the end, it will surely not solve the synchronization issue...
You put the audio and video into your NLE. Decouple the audio so it can be moved along the timeline independently from the video. At the beginning of the video find a place where you can see the audio/video sync (a person talking; a scene change; a loud noise, etc.). Sync that point. Go to a spot near the end of the video and do the same thing. The amount that you have to move the second point shows how slow or fast the audio is compared to the video (if the problem is caused by having one of them run at a different speed. Stretch or compress the audio by that time, using a tool that does not alter the pitch. However, if you suspect the problem was caused by a speed change that didn't change the pitch, such as 24-->25 fps speed up for showing film on PAL video, then don't do any pitch correction.
Last edited by Anotia; 12th Aug 2019 at 15:10.
There is indeed a small duration discrepancy, but the reports above seem to have been made from already remuxed or recompressed files (it's unlikely that a video stream available for download would be muxed with mkvmerge, or an audio stream encoded with Nero AAC, those files were most likely made using MeGUI which includes both), which makes it difficult to diagnose. What does MediaInfo say about the streams as they were downloaded ? And what did you use to download them ?
Perhaps a link to the web page where those streams can be found would be more helpful. Perhaps a simple ffmpeg or youtube-dl command would do the trick.
I'm not sure what “FPS” means for an audio stream.
EDIT : MeGUI is just a convenient all-in-one GUI (graphic user interface) for a bunch of individual tools, which can be used independently. For instance, it includes mkvmerge, which can mux video/audio streams into a Matroska / MKV container ; mkvmerge is also included with MKVToolNix, which offers more control over the process, and it can be used as a command line tool as well (commonly referred to as “CLI” = command line interface). MeGUI also includes mp4box, which can mux video/audio streams into a MP4 container (more restricted than MKV with regards to the format and number of streams, but should work fine with 1 H.264 video stream + 1 AAC audio stream), and can also be used as a command line tool, or with a dedicated GUI like YAMB (but those generally offer less control than the command line interface).
Another command line tool, ffmpeg (also included in MeGUI and in many conversion softwares – including some commercial ones, despite being an open-source project), is (much) more versatile and can directly mux and/or transcode video and audio into pretty much any existing format and container, with a gazillion of switches and options to accomodate any possible requirement.
Last edited by abolibibelot; 13th Aug 2019 at 12:48.