I have two video files. One is in mkv and contains an audio stream I want. The other is an mp4 and contains the video stream I want. I used MKVextract on the mkv and I used MP4Box on the mp4. I then mux them MKVmerge and I receive no errors. When I try watching the output file there are synchronization issues. I've tried adjusting the audio delay, but that doesn't really help. I can adjust the audio stream so that it synchronizes perfect with a certain spot in the video, but it still is unsynchronized with many parts of the video stream. It's like the video stream lags at certain parts. I've looked around and haven't really seen anything relating to my problem. I've tried a handful of other tools, but I'm receiving the same results. I'm not sure what other info you need from me as I am completely new to all of this. Thanks for your time!
No the video is slightly longer. Before I've extracted both streams they are the same length, but once I've extracted the video, it is longer then it should be. I've looked at it more and I've see the spot that is lagging in the video, it is in the opening credits.
If the audio is shorter than the video, it has to be stretched to the same length. It could be demuxed from the video and loaded into the likes of Audacity as a wav. An alternative is to run Audacity and click 'Edit' > 'Preferences' > 'Libraries' and install the suggested downloads. It may now be possible to simply drag the video file containing the audio directly onto the window without demuxing. Adjust the length of the audio then 'File' > 'Export' the new audio and mux it with the video. http://www.afterdawn.com/software/audio_video/audio_editing/audacity.cfm
Well I tried what you suggested, but I'm still having the same problem. I can even take on of the videos, demux the audio and video streams, remux them, and the output ends with the exact same problem : \
