Subtitle Workshop loses sync if time controls are used?

[Antaeus Feldspar]

I'm using Subtitle Workshop 2.51 to sync up subtitles with video files. (The video files are being ripped from DVDs created by a Funai DVD recorder; the subtitles are being created by using ccextractor on the MPEG2 video files. I've been using .srt format, primarily.)

Here's my problem -- If I load the subtitle and the video and let them play from the beginning without interference, they appear to sync up fairly well, with a few exceptions that I'd like to correct. However, if I try to move to anyplace else in the timeline, the sync is lost: Suddenly the subtitles that were matching up perfectly with the spoken dialogue are appearing a number of seconds after their corresponding dialogue.

Obviously this makes it all but impossible to use the program to adjust the timing of subtitles, if I can't see the result of choosing a particular time value except by starting the video from the very beginning and letting it play without interruption. Is there something I can do to keep the video preview from losing sync like this?

[fvisagie]

Hi, in my view this sounds more like a symptom of encoding format. Your video file probably has many P and B frames, and also few key frames. Linear decoding and play are straight-forward, but jumping non-linearly to some precise different time stamp becomes a big problem.

Since SW uses the system default player you can't do much there. You could watch the movie, subtitles and timing in a good external player (MPlayer might do the trick for you). A better way, if you want to continue working within SW, is to use a specially encoded version for working in SW with. If your video file and the SW version are encoded from the same source to the same frame rate etc., you'll have a very nicely working subtitle editing set-up.

Regards,
Francois

[Nelson37]

You are not alone, I and many others have had the same experience. You can't scrub forward or back without losing synch. You may, or may not, be able to do it ONCE or possibly begin playback at a certain point.

The same files authored and burned to a DVD-RW for testing play perfectly in a standalone player, the VOB files on the hard drive play perfectly on the PC, with FF and RW posing no problem.

Most who report this seem to be using real-time encoded MPG files, this may be the source of the problem.

I happen to also be using CC files converted to SRT, but the SRT files are fairly standard and I don't see how this could be a factor. Did not notice this CC conversion with other users having the same synch issue.

I have also experienced this with other subtitle programs and software players, whatever is causing it goes away once VOB files are created. Subtitle Workshop has worked very well, otherwise.

Somehow, both subtitle and audio synch are more "firm" once the files are authored. By that I mean rock-solid, compared to somewhat "loose" with the original MPG files. Unaltered playback is fine, but no FF or RW. Going back to definite findings from my SVCD days, the muxing and packetizing is where the problem lies.

[Antaeus Feldspar]

Okay -- can someone give me pointers on how to do this? I thought that recompressing the file using VirtualDubMod and AviSynth would do the trick but I spent several hours discovering that no, it really just gives the same results.

[fvisagie]

Hi Antaeus Feldspar,

See https://forum.videohelp.com/topic339661.html#1770415 for some more background and suggestions. The issue in your case is probably that, during recompressing with VirtualDubMod, you used some MPG-type encoding format (e.g. MPEG-4/XviD/DivX?) and didn't specify sufficient keyframes.

Kind regards,
Francois

[Antaeus Feldspar]

Francois --

Thank you!! I managed to get it exporting at 25% video quality but keyframes every 5 frames. I tried it out in Subtitle Workshop and this time I can move pretty freely in the file without losing sync!

-- AF

[pagali]

Francois --

Thank you!! I managed to get it exporting at 25% video quality but keyframes every 5 frames. I tried it out in Subtitle Workshop and this time I can move pretty freely in the file without losing sync!

-- AF

I've often had the same problem with SW. When I first read this thread, I tried the method of making a low-quality copy in VirtualDubMod with keyframes every 5 frames, and it worked great!

Now I want to do it again, with a foreign movie that needs the subtitles resynched... but every time I try it the "Force Keyframes" area in the "Select Video Compression" dialog is greyed out, both for Divx and Xvid codecs. I can't seem to find anyplace else to change that setting. Any suggestions?

[pagali]

^^ Anybody have a clue about changing the Force Keyframes setting?