Does Sage play files at 29.97fps or 30fps?

[Jere_Jones]

As may be obvious by my previous post, I use closed captions. My wife is a Spanish speaker and the CC's help her keep up and also learn English. Hence, CC's are important to me.

Thanks to merrypig and malore (and some of my own code), using closed captions in Sage is almost seamlessly implemented.

There is one remaining problem -- keeping them sync'd with the video.

In a brief exchange with malore concerning how he implemented SMI files in his STV, he brought up the possibility that Sage might not be reporting the correct time of the show.

So I did an experiment. I had recorded CSI last night, generated the SMI and copied it all to my laptop.

Then I played CSI on both computers (Sage on the desktop, Zoomplayer on the laptop) starting them both at the same time.

The CC's on both computers displayed at exactly the same time throughout the show. Since I had the displays side by side, it was easy to see them show up, change, etc and note that they were perfectly timed together.

Zoomplayer stayed perfectly sync'd with for the entire show. I'll call this the reference.

CSI on Sage gradually ended up 4 seconds ahead of CSI on Zoomplayer. This is with the CC remaining together. Close to the end of the show, someone would say something and the CC would show up 4 seconds later.

Am I making sense?

4 seconds fast in one hour. The math works out to playing a show at 30 fps that was recorded at 29.97 fps.

So the question becomes: Is this a decoder problem? Or a Sage problem? I use the decoder that came with my PVR's. For me it seems to give the best quality and stability.

Any ideas?

[malore]

This might be related. If you edit out the commercials from a file, keeping the same name, and play it through SageTV Recordings, the time display will still indicate it is full length. So I'm wondering if SageTV is just guessing at the times based on file position or something similar.

[Jere_Jones]

That may be. Sometimes I can resync the captions by jumping a large distance in the show and then jumping back. Maybe it forces it to "re-estimate" the time.

Sage Developers,
Is there anyway to fix this or will it require a complete recode?

Malore,
You made this for SMI files which use timecodes. What about SUB files? They use frame numbers and might not be subject to the same problem. I would imagine that they are also easier to parse. Is this something that is possible?