Subtitles out of sync - how to do this workaround?

#1

I am recording from an HDHomeRun Prime with Cablecard using Windows Media Center. I am using the paid for comskip for commercial detection (seems to work just about spot on). However, the subtitle file is pretty much always out of sync. I have played with the subtitle offset settings many times, thought I got it right with a test file, but subsequent recordings are not correct. Its like the offset needs to be different for each recording.

So, my thought is to do the following:

  1. Identify commercial segments
  2. Convert full length video into MP4 while burning subtitles
  3. Cut MP4 commercials out

This should result in having the subtitles burned in before cutting the video, so they should not be out of sync ever. Thoughts? How would I set it up to make this happen?

Thanks.

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#2

Is this possible?

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(Goose) #4

Subtitles can be tricky due to the nature of MPEG recordings.

See this post on adjusting Subtitles sync:

Identify the type of sync issue you’re facing, is it progressive or constant and you can then adjust the settings accordingly.

What you want to do can also be done. See the advanced commands sections on how to delay cutting advertisements to AFTER the conversion, set PreConversionCommercialRemover=false

You may also want to refer to the UniversalCommercialRemover setting as appropriate.

As for burning the subtitles into the video use the SubtitleBurn=true command in your profile

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#5

I have tried those techniques… what works for one recording, doesn’t work for the next. Hence I am hoping to use the built in ability to run commands at the very beginning to do what I want. Its a matter of what command do I need to run to make this happen. I am familiar with all you referenced.

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(Goose) #6

Not sure what you’re saying. If you’ve implemented what you wanted to do then where’s the issue? If the subtitles are burned into the video before being cut, what’s the problem?

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#7

Sorry, to clarify, I haven’t figured out how to burn the subtitles before doing the commercial detection / cutting.

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(Goose) #8

As I had mentioned set PreConversionCommercialRemover=false and SubtitleBurn=true in your profile.

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(dale) #9

Hi there. I realized this is an old thread but I have also been struggling with the closed captions being in sync only after commercial cuts have been done. I have searched the internet for help and there are a couple of threads talking about it. This is one of them.

I’m not sure but I’m betting everyone is encoding into MP4 while doing the commercial cuts. That’s what i was doing and I tried adjusting the subtitles with the settings but it seems like, different shows and different movies behave differently. Sometimes being progressive, sometimes being just a couple seconds for the whole show, sometimes its like 20-30 seconds off.

I need my subtitles. I don’t read them all the time but sometimes I can’t understand what people are saying and want to see what they said.

The solution or workaround if you will, is to do the Comskip, and leave the Conversion profile to TS Unprocessed. Not sure why, but the Subtitles do not go out of sync this way. Then have your files placed into a temp folder. Where you can later convert them to mp4, as another task.

I use Plex and I just set it to watch my Temp Folder and my TV Shows folder so that way as soon as the commercials are cut I can watch the show and the show will still be there after it gets converted someday later.

Some additional info is that the Comskip and saving to temp folder only takes between 5-15 mins. My mp4 conversions with Comskip were taking 30-120 mins. So your shows are available with no commercials a lot quicker. If you want to watch them the same day you record them this is the way to go.

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#10

I did as suggested, and it works for me. First I burn the subtitles into the mp4 stream, and then cut the commercials out after.

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(dale) #11

One additional piece of information if anyone is interested in fixing their mp4 files that already have been converted. I tried a bunch of subtitle fixing apps and most work but take are hard to use when the subs are out of sync by different amounts at different parts of the movie or show.

I found this amazing piece of software called SubSync or Subtitle Speech Synchronizer. It uses the subtitle track and the audio track from the movie or show and uses voice recognition to sync up the 2 tracks. All the MP4’s that I had cut commercials out of were auto synced its like magic takes between 2-5 mins. The only files it couldn’t sync correctly are the ones I tried to fix with other subtitle adjusting programs first then tried to run them through the subsync.

Here is a link to the website that I found the program on.
https://www.linuxuprising.com/2019/01/subsync-auto-subtitle-synchronization.html

It runs on Linux and Windows.

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(dale) #12

Ya I was going to do the burning into the show but my wife doesn’t like subtitles on some of her shows. So i need to have the option to turn them off sometimes :frowning:

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(Goose) #13

You could accomplish the same results as @machyy1 without burning the subtitles, only set PreConversionCommercialRemover=false in your profile.

Now it will cut the commercials after converting which should keep your subtitles in sync.
(cutting commercials before conversion leads to faster conversions but has a side effect that some recordings, depending on the I frames/GOP boundaries, could have subtitles go out of sync)

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