VSFilter and frame-based textual formats

[dr.Prozac]

Hi !
I've been encoding movies for a quite long time but just now I've noticed one thing. I'm talking about using VSFilter in TextSub mode for textual subs support. Ssa, ass, srt - all are supported correctly. The problem refers to MicroDVD frame-based format with .txt or .sub extensions. If the movie has 25 fps the synchronization is proper but when loading 23,976 or 29.97 fps clips subtitles get out of sync. I used the following simple script to check the results
LoadPlugin("x:\VSFilter.dll")
AVISource("x:\y.avi")
TextSub("x:\MicroDVD_subs.txt")

Does anyone know the reason of this ?

[lamer_de]

srt and ssa are time based (=display subtitle at 00:01), microdvd frame based (=display sub at frame 24). So it's obvious that the microdvd sub will get out of sync when you use a source with another framerate.

Solution: Use a framerate converter if you want to keep the microdvd format or convert it to a timebased one.

CU,
lamer_de

[dr.Prozac]

srt and ssa are time based (=display subtitle at 00:01), microdvd frame based (=display sub at frame 24). So it's obvious that the microdvd sub will get out of sync when you use a source with another framerate.
Yes I know. The subtitles were properly converted to a framerate relative to the movie. They were all fully synchronized (checked by MPC, ffdshow & VobSub). It is just something wrong with VSFilter when executing such avs srcript. After I had discovered that I tried to use different versions of the filter but it didn't help.

[Raziel6969]

Hello,

Frame based subtitles are evil, avoid at all cost!
convert to Time based, there are many easy tool for the job!
There is nothing wrong with VSfilter, at least in that case;
I did have problems playing subs in CD, or DVD backup that plays
fine at HD, and some weird 'diagional green lines', but to me are
the only troubles that i ever had.

Bye.

:sly:

[dr.Prozac]

The thing is that I don't need subs for my own use. I prefer Advanced SubStation Alpha scripts when encoding video. This is only theoretical deliberation. I have just created the soft based on AviSynth and VSFilter and one of the features of this app is adding MicroDVD subs to the movie via avs scripts and VSFilter. This is why I have noticed it doesn't work as it should. Look at AutoGK for exaple. There is also an option to add external subtitles. You can choose txt and other formats but it also doesn't work when loading MicroDVD subs and they are out of sync. Maybe not so many users use this hidden option (activated by ctrl+F8) and also nobody writes about it.

[lamer_de]

So vobsub (meaning the on-the-fly-version, not vobsub as in loading idx/sub files) works and textsub doesn't? How is this possible, it's the same dll (vsfilter.dll)?

CU,
lamer_de

[dr.Prozac]

So vobsub (meaning the on-the-fly-version, not vobsub as in loading idx/sub files) works and textsub doesn't? How is this possible, it's the same dll (vsfilter.dll)?
Well that's a question and something I don't understand. Really strange. I have made many tests. My friends from our Polish forum also did. Please try to create the same script and use the source with other than 25 fps, load .txt or .sub MicroDVD subs and finally play that scrip in your player. This is really a riddle for me :confused: