Does the Terapin record closed captions?

[McPoodle]

I've seen a couple of posts on these forums that implied that the Terapin VCD Recorder captured closed captions. I was wondering if any North American Terapin owners can confirm this.

The reason I'm asking is that I would like to reverse engineer the VCD closed captioning format to allow PC VCD authors to include captions in their discs.

--McPoodle (author of the SCC Tools suite of DVD closed captioning tools)

[GreatSinatraFan]

I haven't played with my Terrepin VCD Recorder for a while now; since I got a capture card and a dvd burner; but to my rememberance; it will record exactly what is on the screen. No closed captions; unless the closed captions are present on the screen while recording.

Speaking of the Terrepin VCD Recorder.. I wanna sell mine; bought it new for 220 bucks a year ago; I still have everything that came with it, but the box it came in. Any reasonable offer will be considered. (buyer must pay shipping) 8)

[handyguy]

Adding captions is more complicated than that if you have a PC, on a Mac is supposed to be easy. On a PC you need a special card & those always seem to be $1500. I haven't seen a VCD with captions either. I could do that with a Telecaption II decoder box though. It makes them OPEN captions instead of closed if you use the right output on the back then feed to your PC & capture as vcd.

[Cornucopia]

I have a Terapin. Did a transfer just 2 days ago to check on this very thing. Unless the CC info is being stored within the MPEG stream itself--for instance in the user data section, which I very much doubt, then the answer is NO.
There is no structural difference at all between this and a normal Terapin VCD recording.
How do I know the normal recording isn't closed-captioned? I made the master on Betacam myself, having converted a PPT file to stills/animation and output to tape. Then I sent a copy to CaptionMax, where they added Captioning and gave me a CC'd Beta back.

Keep up the quest, more of us would like to know...
Scott

[donpedro]

Well... as far as I know Closed Caption is part of video signal. Some line number XX. Standalone DVD Recorders usually save them as well as VCR's. Not sure about VCD or SVCD or Terapin.

[McPoodle]

In answer to Cornucopia, the vague document circulating the web about VCD's (based on an equally-vague PDF on Philips website) state that VCD closed captions are in the CAPTnn.DAT file and in the "user data area". Since this is defined both as a section of the MPEG and as the tracks on the CD where the MPEGs (and CAPTnn.DAT) reside, I had long thought that there was only one mechanism, until I got my hands on an old commercial VCD with a CAPTnn.DAT file and the captions didn't show up in any DVD player I tried. Further research showed that that file was intended only for the CD-I player. The source code for VCD Imager includes a comment that closed captions are a type of user data (like the scan data offsets), but when I contacted the author of that software, he had misplaced his notes. Just my luck that the VCD I had was in PAL format and lacked MPEG user data. By the way, according to that source code, the caption packet should start with hex bytes 00 00 01 b2 11 (scan data has 10 instead of 11).

Anyway, what I was wondering was if anyone played one of their Terapin VCD's with closed captions turned on on the TV and managed to see anything.

[Cornucopia]

I'll try that later today...

[handyguy]

CC's are added on line 22 of the picture. I don't see how that would work with VCDs in a dvd player. Thats for NTSC, PAL has its own formats.

[McPoodle]

Line 21, actually. DVD works by taking the closed captions stored as user data inside the MPEG file and turning that into VBI signals as part of the output. I suspect that NTSC VCD's work the same way (but with a different user data format than DVD's), but since there haven't been any commercial NTSC VCD's since the early 90's, I'm hoping that the Terapin recorder will provide the information I need.

Speaking of which, Cornucopia, what was the result of your test?

[Cornucopia]

Sorry I didn't get back to you sooner, this work week was a nightmare!

Anyway, I still haven't checked the user data sections/streams, but as far as pass-through to decoder, it doesn't look good.

I played the VCD made from the Terapin in an APEX 3201 (which could have something to do with playback), and out to a CC-capable TV. Nothing showed up on any of the CC channel (?) choices.

Let you know more later...

Scott

[Cornucopia]

I still have yet to use a hexeditor on the stream, but so far have not found anything resembling "user data" info for CC.

OTOH, what I have found is somewhat interesting:

1. Terapin uses a regular MPEG sequence header every 1sec + 15 frames (NTSC).
2. It also adds a padding stream automatically. (Not in there, though. I checked--just continuous "ÿÿÿ".....)
3. Video stream is just 1130kbps--so there might be room for extra data.

Another neat (OT) thing I found out is that, while people on these forums have used apps to change things like aspect ratio, etc for MPEG2 and haven't had luck with MPEG1, you can do some of this with the MPEGSequenceMaker, which resides on this site!

Onward...

Scott