I have an MP4 that is fine until the last hour when the audio suddenly becomes out of sync. After running it in VLC player I've found that it is -0.350s out in the last hour. Is there any way to correct this? I've only found programs to correct MP4's where the whole video is out of sync.
I'd convert it to MKV as MKVs seem to be easier to work with. MKVMergeGUI will open it and the remux it as an MKV. It also has as a split function which you can use to split it as close to possible to the point where the audio goes out of sync. Once you've done that and you have the MKV in two parts, you can open the second part with MKVMergeGUI and set the appropriate audio delay, then resave it. Finally you'd use MKVMergeGUI to join the first part to the new version of the second part and resave it once again as a complete MKV. There'll probably be a brief break or glitch in the audio where you originally split it, but there's not much you can do about that. If you really want to keep it as an MP4, a program such as YAMB or MyMP4BoxGUI should be able to resave the new MKV as an MP4 again. Chances are both those programs will also split the original file, set an audio delay and rejoin them as above, but I don't use either of them much.
lol didn't think it would be that complicated but thanks I'll give it a try. I keeps stuff as either MP4 or MKV so I can run them in iTunes so converting it to MKV will be fine.