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|ID||Project||Category||View Status||Date Submitted||Last Update|
|0000475||Cinelerra-GG||[All Projects] Feature||public||2020-07-08 18:41||2020-07-28 08:17|
|Priority||normal||Severity||minor||Reproducibility||have not tried|
|Target Version||Fixed in Version|
|Summary||0000475: Possibility to export subtitles in .srt or .ass|
|Description||Cinelerra currently uses the .udvd subtitle format which is a clone of the .sub format used in MicroDVDs.|
This format has a big problem, which synchronizes with the number of frames.
And this causes problems when one works on a project at a certain frame rate, but wants to make different versions of this video, for example a version at 4K at 60fps another one at 1080i at 30fps and a lower quality one at 720p at 24fps. This is very common today, because it is not the same to reproduce on a large screen as on an HD TV or on a mobile device or tablet.
If the subtitle file uses a frame rate based sync code, I will have to make a subtitle file for each version (remember I change the resolution and frame rate).
The fact that Cinelerra exports only in .udvd (.sub) format means that in these cases it is no longer a good option to create subtitles. And this is a real shame, because Cinelerra is very good and useful for making subtitles.
This problem is solved using a format more in line with what is used today, that is, subtitle files that encode with time, Hours: Minutes: Seconds: Hundredths of a second, when creating subtitles with this synchronization encoding by time the frame rate is irrelevant, and a single file is used for all the versions we make of our video, regardless of the frame rate.
.srt, widely used and recognized by almost all video playback systems, uses the time format, as does .ass, which is also very common.
It is a real shame that Cinelerra does not export subtitles in .srt or .ass format.
The problem of converting .udvd to .srt or .ass with ffmpeg is that this is based on the speed of 24fps and if we have not worked at this speed the synchrony is not good. I have consulted the manual of ffmpeg and I have not found the solution to be able to indicate on the basis of which frames it has to convert .udvd to .srt, without losing the synchrony if I have not worked at 24fps.
I do not know if with mencoder you can, I have not consulted it, the only solution that I have found to convert a .udvd file to .srt without losing synchrony is using the "Gaupol" application, which allows me to define based on what frame rate the .udvd file is synchronized
If it were not for this detail, it could be said that Cinelerra is one of the best subtitle creation tools. Currently it is a good option but it should be used together with Gaupol to be able to convert the created file to more usual and better recognized formats than ".udvd", although if we change the extension to ".sub" most of Players automatically recognize and load the subtitle file. But if we encode the video and change the frame rate, the .udvd or .sub file lose their sync, this is not the case with .srt or .ass files or any subtitle file that uses a time format.
I would like to know if this is possible and if there are possibilities of this change, because I want to write a tutorial on making subtitles with Cinelerra and this point seemed important to me.
|OK, thank you very much, I'll try it as soon as I can.|
With the latest GIT checkin, you can now create Subtitles in srt (subrip), sub (subviewer) or udvd (microDVD) format with srt being the default. The test builds for Mint 18 and Mint 19 include these -- you will see in the upper right hand corner, a "format" box pulldown to choose.
The Subviewer specification says the [Information] and its closer or optional. We do not use mpv or vlc so have not verified correctness with other programs -- just with the specs. Please let us know if problems.
Thank you very much Phyllis. Cinelerra has a very good concept for creating subtitles, convenient, fast, effective. But if you export in a frame-syncing format, everything else is overshadowed. Anyway I will make the tutorial and at the end I will indicate that with Gaupol, excellent application, we can convert the udvd into srt with total precision, with ffmpeg you cannot do it with precision. I have not known, I have not found a way to tell you the frame rate of the udvd file (which is actually .sub) so that it converts without desynchronizing.
What cannot be previewed in real time is secondary and irrelevant. But Cinelerra would be very good and would have no rival in subtitles if it could export in .srt, .ssa or .ass (better)
I said thank you very much.
|Discovering this is disappointing -- "This format has a big problem, which synchronizes with the number of frames." I will find out if GG has any feedback on the possibility of using a .srt file output and how hard that would be to implement. I do not foresee that it will be soon though.|
|2020-07-08 18:41||RafaMar||New Issue|
|2020-07-08 18:41||RafaMar||Tag Attached: Feature request|
|2020-07-09 02:41||PhyllisSmith||Note Added: 0003775|
|2020-07-09 06:50||RafaMar||Note Added: 0003779|
|2020-07-27 00:31||PhyllisSmith||Assigned To||=> PhyllisSmith|
|2020-07-27 00:31||PhyllisSmith||Status||new => feedback|
|2020-07-27 00:31||PhyllisSmith||Note Added: 0003846|
|2020-07-28 08:17||RafaMar||Note Added: 0003854|
|2020-07-28 08:17||RafaMar||Status||feedback => assigned|