This is a rather abstruse problem but I know UKC has a tendency to conceal unexpected sources of knowledge and expertise so here goes...
I have an MP4 video file, and a .srt subtitles file. Using VLC to play the video, it finds the .srt file and the subtitles are nicely in sync with the audio. However, the video playback apps on some of my devices can't use .srt files, so I'm trying to use Handbrake to embed the subtitles in the MP4 file. The trouble is that Handbrake seems to find a few seconds of additional video at the start of the MP4 file, which it includes in the output MP4 file, which then puts the embedded subtitles out of sync by the duration of the additional bit of video.
I've tried editing the extraneous video out of the MP4 file but somehow Handbrake keeps finding it and including it. It's as if the tools I'm using the edit it out don't actually remove the video, they just put a tag in the MP4 file saying "start here", which Handbrake then ignores.
Anyone have sufficient knowledge of this subject area to make any informed suggestions as to what might be going on and/or how to stop it happening?
Push comes to shove I suppose I could edit the .srt file to bump up the trigger times for the subtitles by the duration of the extraneous video - but that looks like it would be a fair old job for over two hours of video
