DVD Architect and closed captioning

RBartlett wrote on 9/22/2006, 5:34 PM

I've recently been researching what options someone who has aspirations for embedding CC content in modern delivery formats has. I believe you'll find yourself bridging an original/legacy system with what is enough to get away with now we are in a more digital world.

Whilst it may be possible to write to the closed-caption decoder of TVs that have this function as standard (North America and some other islands) it is important to point out that DVD-Video is aligned more to the subtitling capability of the DVD players. This is also standard but is worldwide. DVD-Architect supports this format of text overlay on video.

Otherwise, you'll see over at maccaption (and ccaption) that there is some interoperability with NLEs where the the VBI line is mapped in-band into the DV/DVD visible line space (of 720x480 NTSC video). The option is there to have additional out-of-band assets to convey the CC data within the MPEG-2 stream, as additional authored media. However I don't see this being an option in DVD-Architect.

I don't think this makes DVD-Architect illegal for making merchandise for retailing (in North America) as the provision IS there for text-over-video using the subtitling mode (rather than CC).

I'm not sure if the VBI-data is readily acquired (via remapping) on certain analogue->DV products (bridges/camcorders/decks) using the VAUX designated area. However it wouldn't be impossible to consider using maccaption and to attempt to feed this into a lower (than MPEG-2) compression format that you then pop into DVD-Architect through recompression.

This would be a complex workflow and would then give you the quandary of whether to put the CC-signalling in aswell as DVD-Video subtitling.

Most folks with Vegas+DVDA won't be considering spending another $1000 on a CC creation tool like maccaption. For broadcast, syndication and mastering - I can otherwise understand the intention to get the CC encoding completed.

So I do know that the SCC file is of no use to you directly with these Sony products. However it might be possible to go around the NLE loop as described here:
http://www.cpcweb.com/Captioning/NLE-DV-HardwareCompatibility.shtml

Once you have the analog version - that might be compatible with a DV digitizer. I'm not in a "CC" country (we have teletext here) so I don't know if you can record CC to DV from "air". Yet if you can - this could be the convoluted path that you need.

Otherwise I'd look into supplementing what you have with Encore or DVD Studio Pro.

My concluding comment is that as the computer and TV world converges we will see more and more computer-monitors in our living spaces. These won't have CC decoders in them. So the DVD-Video and DVB (MHEG/HTTP etc) formats are going to take over in time. I'm not sure if the legislation is following as quickly, so CC will remain a distinct consideration until this all sorts itself out.

I hope these words are of some benefit to you Cooldraft?

Cooldraft wrote on 9/23/2006, 6:41 PM

Yes, I was considering subtitleing, but then rented a DVD that had CC on it and thought that I would to it this way.

bStro wrote on 9/23/2006, 7:28 PM

Yes, I was considering subtitleing, but then rented a DVD that had CC on it

How is the closed captioning accessed? Through the DVD's options or the TV's?

Rob

RBartlett wrote on 9/24/2006, 4:01 PM

Closed captions are decoded by the TV. Making the assumption that you use a TV and not a monitor/projector.

However they can be authored in (just as we can indirectly request macrovision, CSS or through even more convoluted techniques - the likes of CGMS and watermark copy protection). Seemingly DVD-Architect assumes subtitling is the last word in providing optional text.

Closed caption is in-band with the video data. The CC information is not generated locally by the DVD player.

The best of both worlds would not allow the subtitling to go into the text area of the standard spec CC decoder built into many but by no means all TV sets. Although I'd imagine it fairly useless to provide the same text via either path.

With mac-caption or ccaption - it would be feasible to use an alternative "angle" on DVD to simulate a CC decoder. However I suspect the main intention of the original post is that CC will be given.

If CC, or the look of it is required. I'd tend towards providing subtitling and to force it to be shown in disc properties (a DVDA3 and DVDA4 feature - afaik). Simulating the font/background in the subtitle rendering parts of DVDArchitect.

Generating CC might still be advantageous for Vegas for broadcast use. DVDA could then benefit if the MainConcept MPEG-2 compressor keeps the data blobs (sent in-band) intact.

[as I understand the technology to require even though there is a good amount of noise tolerance for the analog spectrum]

bStro wrote on 9/24/2006, 4:54 PM

Yeah, I know it's normally decoded by the TV. I was just trying to determine, in a roundabout way, whether the DVD that Cooldraft rented really was using closed captioning or just faking it through mislabeled subtiling, alternate angles, or something. So, I asked how this "closed captioning" was accessed while watching that particular DVD.

Rob

RBartlett wrote on 9/25/2006, 1:25 PM

I'd like to know if that is the case too Rob. Sorry for being all high and mighty with you - I was being all factual instead of thinking. I've not spent enough time around here lately to recognise the experts from ther perts. ;) I hope you understand?

bStro wrote on 9/25/2006, 1:36 PM

No problem. I don't know a lot about closed captioning, just that it's embedded in TV broadcasts -- so your post was informative overall.

Rob

filmy wrote on 9/25/2006, 5:14 PM

There have been a few threads over in the video forums on this topic. I brought it up last year as there is a requirement for CC'ing in the US and pondered if Sony would impliment it in the next Vegas+DVD release. As of right now they have not, but also the whole CC thing, as I understand it, is an NTSC only item. Maybe someone in the PAL countries could say what their law/requiremnts for the hearing impared are.

Here are two threads:

Closed Captioning on Vegas 5.0. In this thread I also post a link to some DV and CC info as some people think that CC can't be included in that.

Adding/placing closed captioning text. (THis is the thread where i said I mean vegas loves to have things available for broadcast - scopes, the "broadcast colors" filter - so i don't think it would be that far of a stretch to think someone might be working on a CC portion.)

Cooldraft wrote on 9/25/2006, 7:20 PM

How is the closed captioning accessed? Through the DVD's options or the TV's?

It was enabled on the tv, no setting on the settop was required.

Cooldraft wrote on 9/25/2006, 7:26 PM

I just burned myt FIRST DVD studio pro DVD and I guess I have a lot to learn (or it is aweful) The SCC file DID indeed work on my DVD. The DVD was indeed closed captioned. Guess I am spoiled with DVD A and the way that things are done withn DVDA. Guess I am back to lynda if I need this feature (To learn more about DVDStudio)

RBartlett wrote on 9/25/2006, 11:59 PM

You could have a broken worflow...........

Edit in Vegas, render for DVDSP

compile a linear "single movie" piece in DVDSP,
render to files,
demux to .MPG (or .m2v/.ac3)

Author in DVD-Architect with menus, chapters and the likes in the manner you have become accustomed to.

I'd imagine that DVDSP has made the SCC file in-band with the video data. So as long as the parameters conform to what DVD-Architect thinks doesn't need recompression - that might work.

At some point DVD-A may have CC conformance. I'm not sure what legislative problem there is with selling a DVD that only has subtitles. That seems like the law being an ass and not keeping up with the times.

--------------------------

CC would be acceptable in PAL but only for those with external adaptors.. Subtitles are probably legislated towards fair-access somewhere (in retail product) and having CC instead maybe a cop-out for imported films. Broadcast is possibly self governed, but most programs use teletext and live-stenographers (news etc) or cottage industry stenographers (everything else). The concept of DVD-Video is well detached at this point.

I doubt DVDSP is impossible to grasp. Yet you may not have considered the above workflow option?

GeorgeW wrote on 9/26/2006, 5:42 AM

RBartlett, using the stream from another application that will mux in the CC will "almost" work (I used DVDLab PRO 2.x to mux in a CC file).

The problem is that DVDA does not turn on the CC Flags in the IFO's, so this might prevent turning them on/off using a software DVD Player (for playback from a computer). However, it could still work when using a set-top dvd player with a TV that will display the CC (I just tried it, and was able to get the CC line to show on TV even though the CC Flags were TURNED OFF in the DVD IFO file).

EDIT -- this assumes DVDA does not recompress the video. When it does recompress, it appears the CC is lost.

Cooldraft wrote on 9/29/2006, 3:00 PM

How to mux, demux? Insert the scc file???

RBartlett wrote on 9/29/2006, 4:20 PM

How to do it - well unfortunately - All outside DVD Architect.

Folks here have contributed with mentions/props for:

ccaption/mac-caption (create media, more typically for broadcast/legacy-pro-tape SD formats)
DVDSP (seemingly does all you need in-house)
IFOEdit (tweak flags for PC playback where video object is already embedded)
DVDLabPro2 (emulating scenarist functionality)
Scenarist (fwiw by cost comparison)

What I'm still not sure of is whether it is part of the general hardware implementation spec to encode the analogue patterns from what is essentially an out-of-band metadata stream in the mux, or whether there is another DV-like approach for driving line21 by remapping a visible line into the VBI through in-band picture/field data - or either/both.

Generation of CC into the output by a DVD player appears to be a mandatory requirement not unlike the requirement to mixdown 5.1 audio into stereo.

So all NTSC (and probably the majority if not all PAL players) would have to have a CC encoder. That if this were an a device to serve a VHS deck would cost $1000-$7000. So I assumed that the generation was of line-21 (or the VAUX area in the displayable part of the screen) was included in the VOB IBP stream and it seems that is quite incorrect. It appears that CC fits in the same scheme as CGMS .

I think I've learnt that there is an out-of-band but in-VOB approach to providing metadata that provides the DVD player (hard or soft) with the necessary means to encode this CC "modulation" locally to place these byte streams back in-band on the player/deck itself.

Just as we grasp all this, we find out that it is defunct by the time we reach HD playback and display technology......