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Barrett
02-26-2003, 12:48 AM
I have a SA Tivo, I finally have my method of getting to DVD-R pretty quick and easy as I found out how to get the Tivo to encode at DVD Resolution, so there is no reencoding of the video needed, however the video i extract from the tivo ALWAYS has white fuzz lines at the top of the picture, they are kind of annoying, I can get rid of them by using the Clip frame function in TMPGenc, but then I have to reencode the whole file.. which is a pain. Is there any way to get rid of these without all that? What makes them appear?

laserfan
02-26-2003, 10:30 AM
Are you seeing this on your TV? Normally a regular TV overscans such that you won't see this information.

Barrett
02-27-2003, 02:51 AM
Originally posted by laserfan
Are you seeing this on your TV? Normally a regular TV overscans such that you won't see this information. yes, is there any way to clip these top few lines without reencoding?

Wes
02-27-2003, 09:11 AM
Yea, I just leave it alone since i can see them on my regular TV since they are in the overscan area.

Barrett
02-27-2003, 09:16 AM
ok, i just burned the show to dvd-r and the lines arent there.. but when i played them on tv with tv-out they were there, so nothing to worry about.

Wes
02-27-2003, 02:13 PM
Ah, you use TV-out. No wonder you see them. If you play it on a standalone DVD player and play it on TV, you won't see those over-scan area.

A.C.
03-12-2003, 04:03 PM
I've just started doing extraction, and I notice these same white lines. I'm using windvd to play the m2v file after it's been extracted and tytooled into a playable format. Are these the same lines? Or do I have a different problem?

ctsshack
03-12-2003, 04:56 PM
That is the encoding for closed caption for the hearing impaired. You can't see it on a regular TV normally. It's on most broadcasted shows. You'll probally noticed that it will be gone from some commercials that are not close captioned.

Barrett
03-12-2003, 05:36 PM
Originally posted by A.C.
I've just started doing extraction, and I notice these same white lines. I'm using windvd to play the m2v file after it's been extracted and tytooled into a playable format. Are these the same lines? Or do I have a different problem? yeah it did that for me too, you won't see them if you watch them on your tv.

AlphaWolf
03-12-2003, 05:51 PM
Thats why you set your tv encoder to overscan mode.

Barrett
03-12-2003, 06:41 PM
Originally posted by AlphaWolf
Thats why you set your tv encoder to overscan mode. tv encoder? What are you referring to.

AlphaWolf
03-12-2003, 08:06 PM
You know, the hardware that encodes the signal into NTSC/PAL/What have you. I don't know of any that can't switch to overscan mode.

jmcclain
03-18-2004, 11:10 AM
You know, the hardware that encodes the signal into NTSC/PAL/What have you. I don't know of any that can't switch to overscan mode.

Hum...not sure what you are talking about here. I'm using the MPEG2 playback on an HTPC PVR in my living room. I use the DirecTiVo to record shows, and then pull off all the video to a central computer to allow the HTPC PVR to play it all back from a player (WMP, BTV, etc). The output is RGB at 1080i. The lines are very obvious, and it DOES NOT show up in any PVR-250 captured video. Sure would be nice if one of the tools could automatically strip that line out (over scan or not, it is still in there, and not normally there on most MPEG2 video streams that I play on my computer...including DVD rips).

Regards,

-Jeff

FredThompson
03-18-2004, 12:08 PM
The lines are very obvious, and it DOES NOT show up in any PVR-250 captured video. Sure would be nice if one of the tools could automatically strip that line out (over scan or not, it is still in there, and not normally there on most MPEG2 video streams that I play on my computer...including DVD rips).The FTC requires closed caption data to be encoded in vertical line 21 of TV broadcasts. It's also designed to be robust enough to survive 2 generations of VHS copying. You don't see that, or fuzzy encoding on the edges with DVD content because the data is handled differently with that medium. The white stuff is part of the encoded data and can't be "stripped out" without re-encoding. Try a video player designed for TV out which supports overlays and locked aspect ratio resizing or decide to pay less attention to the edges.

That PVR-250 probably doesn't capture the entire video frame or it's resizing the playback.

sanderton
03-18-2004, 12:10 PM
DVDs don't have any data in the VBI, so the line is black, but it's still there. Presumably the signal source for your HTPC also has no VBI data stream.

On PC, run it full screen and adjust the monitor so the line is off the top - which is all that your TV does!

If it's a TV output from the HTPC and you can still see the line, you probably don't have your TV geometry set quite right.

jmcclain
03-18-2004, 04:59 PM
If it's a TV output from the HTPC and you can still see the line, you probably don't have your TV geometry set quite right.

It is NOT TV output. That is sorta the whole point of having an HTPC PVR...to make use of 720p/1080i display resolutions and DVD playback at higher than 480p resolution (plus, I can avoid the whole 3:2 pull down involved in trying to play back to a 30fps display standard that is no longer required with an HDTV/computer). So, I routinely play back the DVD's on my pc out to RGB or DVI on a HDTV at the ORIGINALLY encoded 24fps MPEG2 source rather than doing 3:2 pull down and then deinterlacing back for progressive display.

jmcclain
03-18-2004, 05:02 PM
That PVR-250 probably doesn't capture the entire video frame or it's resizing the playback.

Hum...wonder if the PVR-250 just blanks that line in the recording or if it does, indeed crop the incoming signal. Are you certain that a DirecTV or Tivo is not blanking that line itself before sending it out to the TV, rather than the TV not being able to see it? I have no idea, just curious. Guess if I had a stand alone CC device, I could see if it was picking up CC content coming out of the DTV tuner. I'll start looking. Thanks for all the thoughts on this!

-Jeff

malfunct
03-18-2004, 05:38 PM
Hum...wonder if the PVR-250 just blanks that line in the recording or if it does, indeed crop the incoming signal. Are you certain that a DirecTV or Tivo is not blanking that line itself before sending it out to the TV, rather than the TV not being able to see it? I have no idea, just curious. Guess if I had a stand alone CC device, I could see if it was picking up CC content coming out of the DTV tuner. I'll start looking. Thanks for all the thoughts on this!

-Jeff

The DTivo most definitely passes on the CC info to the tv because my tv can show the CC text if I turn that mode on.

FredThompson
03-18-2004, 05:44 PM
Are you certain that a DirecTV or Tivo is not blanking that line itself before sending it out to the TV, rather than the TV not being able to see it?Yes

VCRs and camcorders also record the entire frame.

The only devices which don't show the entire frame are TVs.

Extract a stream and compare a frame on your TV to the same frame on computer playback.

This is why the fuzzy edges of DirecTV feeds don't show on most TVs.

sanderton
03-18-2004, 07:19 PM
It is NOT TV output. That is sorta the whole point of having an HTPC PVR...to make use of 720p/1080i display resolutions and DVD playback at higher than 480p resolution (plus, I can avoid the whole 3:2 pull down involved in trying to play back to a 30fps display standard that is no longer required with an HDTV/computer). So, I routinely play back the DVD's on my pc out to RGB or DVI on a HDTV at the ORIGINALLY encoded 24fps MPEG2 source rather than doing 3:2 pull down and then deinterlacing back for progressive display.

Confused. You say it's not output on a TV, then you say it's output on an HDTV. Which is it?

I'm not talking about any particular TV standard, HDTV or otherwise, but simply the fact that TVs don't display the whole picture; if yours is showing the VBI line then its geometry can't be set right as that line is in the overscan and should be off the screen.

jmcclain
03-19-2004, 03:46 PM
Confused. You say it's not output on a TV, then you say it's output on an HDTV. Which is it?

I said "it is not TV output", which is not the same as not being output to a TV of somesort (read my original post again). It is not output on a standard def TV over RF or SVideo TV Output. It is output from a computer video card to RGB inputs at 1080i. Sorry to confuse you.


if yours is showing the VBI line then its geometry can't be set right ...

seems like you are over generalizing a little bit. What I CAN agree on, is that it is not set at the exact SAME geometry as the original 4:3 aspect 480i recording sorce. That doesn't make it the wrong, however.

I think I got what I needed from this, thanks for the disucssion. I just need to go ahead and reencode from TMPGEnc with a crop applied. I do think I will go back and compare a snapshot of a hardware capture of the analog output from the tuner, which doesn't show the CC info, to the ty tivo version, and see if the extra scan line is there and just being blanked on the PVR-250 hardare capture version. Makes sense that the output from the Tivo and DTV tuner still has the CC info, if the TV can decode it. I can only assume then that the hardware capture version is cropping it off or blanking it (since it is technically re-encoding the stream to MPEG2 again).

-Jeff

Fugg
03-19-2004, 03:53 PM
I just need to go ahead and reencode from TMPGEnc with a crop applied.

-Jeff
That's a time consuming process that can degrade your quality.
edit
Not that it's a bad thing, it just may not be necessary.

What is the model # of your display and what is the model # of your video card in your computer?

jmcclain
03-19-2004, 05:01 PM
That's a time consuming process that can degrade your quality.

I agree...which was why I was interested in finding a possible way to strip it in the original source.



What is the model # of your display and what is the model # of your video card in your computer?

<snip...big long winded reply deleted in favor of just answering the question>

Mitsubishi WS55411
ATI 9600SE Radeon

jmcclain
03-19-2004, 05:20 PM
Keep in mind that the above is ONE of the playback avenues. I will also be wanting to play it back on the above in a window, and various other media players, as well as on a couple computers (in a window). Just showing me how to stretch an image on some particular display doesn't really satisfy my request (though I appreciate the willingness to try and help, here, please don't take it the wrong way). :D I want this to be the SAME as DVD footage (which DOESN'T have this in it, nor does just about any other MPEG2 source material). I'm not going to be broadcasting this. I would be surprised if the CC data was ACTUALLY part of the MPEG2 macro block encoding (but I probably should look into that a little more before saying that).

Fugg
03-19-2004, 05:33 PM
Oh, well...

I was kinda hoping that you were using a nvida adapter. With the nvida's, you can "zoom" a display to just cut off the top few lines of the overlay display to hide the cc line info while keeping the desktop resolution intact. It works on the primary or secondary display independently.

Reviewing the ATI 9600SE Radeon manual at atitech.com (http://www.atitech.com/support/manualpdf/Rade9600.pdf), it does not look like you can do it with your card.

Once again, I missed. I had to try, at least. Sorry 'bout that.

sanderton
03-19-2004, 05:37 PM
seems like you are over generalizing a little bit. What I CAN agree on, is that it is not set at the exact SAME geometry as the original 4:3 aspect 480i recording sorce. That doesn't make it the wrong, however.

If you feed a TV a signal and it displays on a visible area of the screen part of the signal which is supposed to be off screen in the overscan, that's wrong in my book! :)

FredThompson
03-19-2004, 05:42 PM
I want this to be the SAME as DVD footage (which DOESN'T have this in it, nor does just about any other MPEG2 source material).Not possible.
I would be surprised if the CC data was ACTUALLY part of the MPEG2 macro block encoding (but I probably should look into that a little more before saying that).That seems like a good idea. You don't understand the basics, are confused and you're not "listening".

jmcclain
03-19-2004, 09:19 PM
Not possible.That seems like a good idea. You don't understand the basics, are confused and you're not "listening".

Hum...I'm listening, and even trying to come up to speed on this. I have no doubt that I don't understand much of what is involved in the basics of CC (that is why I said, maybe I should check...admidting that I did not know).

The research that I've done says that the EIA-708B Captioning standard for Digital television does not utilize the line 21 of the VBI (because digital broadcasts and displays sources do not require a vertical blanking interval). Now, maybe DirecTV is still on the analog EIA-608B standard and just multiplexing the CC analog information into the stream (or maybe it is on a completely different standard and just custom encoding the whole analog stream), but everything I've read says that the data contained in the VBI line 21 for CC is not part of the mpeg encoding (and why would it be...it is hardly conducive to the same compression formats that video is). So my original assumption was, perhaps this CC multiplexed data stream can simply be stripped off without corrupting the MPEG encoding, since it should have been done independant of the CC data stream.

http://broadcastengineering.primediabusiness.com/ar/broadcasting_encoding_closed_captions/

Again, I'm sure there is a perfectly reasonable explaination and probably DirecTV isn't even following these new standards that will be the future of digital broadcasts, according to FCC requirements, but I'm not sure someone here will correct my misunderstandings with a sufficiently terse, ambiguous, and condescending reply.

I'll quit wasting everyone's time here.

Thanks,

-Jeff

FredThompson
03-19-2004, 11:41 PM
When you learn some humility and will pay attention to what you're told, perhaps you will learn some things. If you can't handle correction for ignoring or contradicting the information which is shared with you, there's no point in trying to help you. You're in the classic position of knowing enough to be dangerous but you're discounting what has been explained to you.

Subscribe to Voom or quit bitching that past designs don't meet future standards.

ronnythunder
03-20-2004, 01:57 AM
well, regardless of how we got here, here's where we are:

the lines are there. they cannot be removed without re-encoding, period, paragraph, end of sentence. what this or that spec says is irrelevant; the only way to get rid of it is to re-encode.

ronny

jmcclain
03-20-2004, 02:15 AM
Well, after studying the mpeg data files and headers for quite a while and playing around with it, I've finally managed to strip the CC information out of the MPEG from Tytools without having to reencode. Now off to drink some home brew.

-Jeff

P.S. Now I just need to find the thread that goes over how to reverse the tytools process to take virgin MPEG files and try to put them onto a Tivo. Found a couple mentions of it, but no specifics on how to do it. I'll compare the raw .ty files to the final mpeg and see if I can figure something out.

jmcclain
03-20-2004, 02:18 AM
You're in the classic position of knowing enough to be dangerous but you're discounting what has been explained to you.

Dangerous to who, Fred? Your ego? Very sorry. You're in the classic position of being an ass.

-Jeff

FredThompson
03-20-2004, 04:51 AM
Well, after studying the mpeg data files and headers for quite a while and playing around with it, I've finally managed to strip the CC information out of the MPEG from Tytools without having to reencode.
bs

CC is embedded in the video data.

No, dangerous to yourself. No less than 3 very knowledgeable people answered your questions in this thread and you proceeded to insist they were wrong while you demonstrated you don't know what you're talking about.

You're now on my ignore list.

sanderton
03-20-2004, 09:25 AM
Well, after studying the mpeg data files and headers for quite a while and playing around with it, I've finally managed to strip the CC information out of the MPEG from Tytools without having to reencode.

Please share your technique.

sanderton
03-20-2004, 09:31 AM
The research that I've done says that the EIA-708B Captioning standard for Digital television does not utilize the line 21 of the VBI (because digital broadcasts and displays sources do not require a vertical blanking interval).

I don't know about DirectTV, but here in the UK what you say is entirely true, and the broadcasters are supposed to not encode the first half of line 21 into the MPEG for that reason. But some broadcasters do anyway, even though its out of spec - hence the flickery line.

And people complain about the ones that are in spec, because their 16:9 TVs don't autoswitch for those channels (the signal being in line 21, and not being re-inserted by their STB).

ronnythunder
03-20-2004, 01:17 PM
Please share your technique.better yet, he should patent it first - it should be worth a lot of money! :)

ronny

5318008
03-20-2004, 05:02 PM
bs

CC is embedded in the video data.

No, dangerous to yourself. No less than 3 very knowledgeable people answered your questions in this thread and you proceeded to insist they were wrong while you demonstrated you don't know what you're talking about.

You're now on my ignore list.

http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&selm=bcvf3m%24pvj%241%40panix3.panix.com

MPEG encoding tends to destroy CC data, so it has to be dealt with
separately. On a stand-alone TiVo, it's captured and saved separate from
the video data and added back to the video signal when it's played. The
DirecTiVos do the same sort of thing, only of course it's separated by
DirecTV's encoders before it's sent on the satellite.

Welcome to my ignore list, Fred.

Fugg
03-20-2004, 05:16 PM
nevermind...

sanderton
03-20-2004, 07:55 PM
The two are not necessarily inconsistent.

It's perfectly possible that the Tivo reads the VBI data and saves a copy of it for later re-insertion without deleteing the original in the TV signal. So that's still in the MPEG we extract but is overwritten by the TiVo on output.

5318008
03-20-2004, 08:48 PM
sanderton is correct.

Take a look at this ty. (http://tivo-mplayer.sourceforge.net/example-stream/freshgear_cut.ty) If you demux it the resulting mpeg has no white lines. Insert it into your Tivo, turn on closed captions on your TV, play it back and Voila! Captions! This proves the captions sent from the tivo are NOT coming from the mpeg encoded video - in this case, there aren't any embedded in the video at all!

So, what's the deal with the white lines in some CC'd shows but not others? Dunno. It probably has something to do with the capture hardware or mpeg encoders not cropping the frame properly. I'm still looking into it.

SR712
03-20-2004, 09:22 PM
No, but it has all to do with the broadcaster not paying attention to vertical positioning before it leaves master control. Its probably a playback deck out of wack. Sometimes, the person editing the show to tape selects several lines to hold CC data. Its an option. That might not be line 21 you are seeing, either. We also used to embed special affiliate break signals in those lines. WB, I think sends local spots on one of those lines. This has been going on for years, but most people never would know the difference because their TVs are in overscan. DirecTv does nothing to this as they just take the feed and mux it together with the other feeds, and shoot it out.

Sanderson is correct. Just because TiVo breaks out the CC, doesn't mean that the local TiVo is stripping and blanking those lines. Why would they? Why should they?

FredThompson
03-22-2004, 10:40 AM
No, but it has all to do with the broadcaster not paying attention to vertical positioning before it leaves master control. Its probably a playback deck out of wack. Sometimes, the person editing the show to tape selects several lines to hold CC data. Its an option. That might not be line 21 you are seeing, either. We also used to embed special affiliate break signals in those lines. WB, I think sends local spots on one of those lines. This has been going on for years, but most people never would know the difference because their TVs are in overscan. DirecTv does nothing to this as they just take the feed and mux it together with the other feeds, and shoot it out.Such as this...

jmcclain
03-22-2004, 11:40 AM
Please share your technique.


http://www.geocities.com/mcpoodle43/SCC_TOOLS/DOCS/SCC_FORMAT.HTML has some very good read on how the CC data is MUXED in to each of the GOP MPEG streams. I have since found several filters that will strip out the CC data, and it does not require a recode of the original VIDEO content to strip it. Virtualdub - MPEG works great on this (with the proper custom filters).

Regards,

-Jeff

jmcclain
03-22-2004, 11:47 AM
better yet, he should patent it first - it should be worth a lot of money! :)

It would be pretty hard to patent something that already has as much original source material and documentation as what I have found. I take it this is sarcasm, then? I'm amazed at how wonderfully friendly you folks are on this board are. You know, I don't mind if people want to keep stuff secret and elite (especially when it comes to Tivo, since the ones that have put so much time into hacking the Tivo, only have the most to lose by making it mainstream...so I understand). What I do not understand, is how rude and arrogant some of the "lurkers" are here. If you don't want us to know, just don't reply (Fred).

Anyway, I'm stopping my participation in this thread, as I have found what I wanted.

-Jeff

FredThompson
03-22-2004, 01:38 PM
You refused to accept that the CC data is part of the video stream, after being told so by more than one person. You also claimed to be able to remove that portion of the video data without re-encoding which is impossible.

That is not the same as accessing CC data.

Ronnythunder's comment was sarcastic, probably in response to your attitude and impossible claim of removing data from the video data without requiring recompression.

Nothing was withheld from you, whatsoever.

The CC reference you found is quite nice. If it holds valid for all extracted streams, I'll use these routines to show how to do subtitles.

ronnythunder
03-22-2004, 01:49 PM
http://www.geocities.com/mcpoodle43/SCC_TOOLS/DOCS/SCC_FORMAT.HTML has some very good read on how the CC data is MUXED in to each of the GOP MPEG streams. I have since found several filters that will strip out the CC data, and it does not require a recode of the original VIDEO content to strip it. Virtualdub - MPEG works great on this (with the proper custom filters).

Regards,

-Jeffi still fail to see how this is done without re-encoding. just because virtualdub does the re-encoding for you doesn't mean that it isn't being done.

and yes, i'm sorry to say that my post was meant to be sarcastic, but only because you were repeatedly questioning some pretty knowledgable people on topics that are pretty hard and fast.

having said that, if you can give a little more detail about your technique and it can be proven that re-encoding is not taking place, i'll eat this post.

ronny

sanderton
03-22-2004, 06:19 PM
http://www.geocities.com/mcpoodle43/SCC_TOOLS/DOCS/SCC_FORMAT.HTML has some very good read on how the CC data is MUXED in to each of the GOP MPEG streams. I have since found several filters that will strip out the CC data, and it does not require a recode of the original VIDEO content to strip it. Virtualdub - MPEG works great on this (with the proper custom filters).


To quote that page:



Data in MPEG files is organized in terms of packets. DVD closed captions are stored on a per-GOP basis, and are located within the video MPEG-2 file between the GOP Header packet and the (I-frame) Picture Header packet.

In other words, the CC data is not in the video, so what you are seeing is not the CC which TiVo uses, but is stuff actually in the MPEG video stream itself. VirtualDub can of course crop the top line out with a suitable custom filter - but that involves a re-encode.

FredThompson
03-22-2004, 06:35 PM
If CC exists in a U.S. broadcast, it's on line 21. Given the FCC requirement to preserve the CC encoding on line 21, it sure makes sense that a lossy storage method like MPEG TiVos would save the pre-compression data and overlay it on line 21 during playback as you mentioned earlier in this thread. Ergo, the TiVo might not reference the line 21 encoding for playback but that visual encoding is still in the video data.

SR712
03-22-2004, 06:43 PM
Fred- I agree with you, however your claim to FCC regs does not wash with most of what we watch on DTV. FCC has no actual enforceable jurisdiction over cable networks, since they do not use "public" airways. It is nice and even desireable if we follow convention, but not a requirement. Most do.

FredThompson
03-22-2004, 06:54 PM
Perhaps you are confusing the FCC's mandate to enforce decency standards over "open" airwaves with technical requirements. The FCC has jurisdiction over anything which emits electro-magnetic frequencies.

What I was trying to state was the line 21 data will most likely be in the video for portability and interoperability (big word...) between the different groups that work with video. Take a channel like A&E, for example. There are different independent production companies which make the programs. A&E then sends the programming out over DirecTV, Dish, a bunch of cable networks and the people who make DVDs and VHS tapes for resale. Sure, they could use multiple custom formats for CC but that would be a real mess. Since line 21 is the standard for playback equipment, the most convenient way to do this is follow the standard. DirecTV may very well "decode" the data and embed it in the stream but that doesn't mean they remove the line 21 data from the video signal.

I do understand what you're saying, though. It really doesn't matter how CC is encoded when it is sent over "closed" distribution systems as long as there is CC on line 21 of the output.

SR712
03-22-2004, 07:33 PM
No actually, I'm not mistaken. The FCC might have jurisdiction over our composited uplink signal, but not over the video signal(s) embedded in our stream. We can put pure junk on it if we wish. We can backhaul if we wish. We can put data on it if we wish. The signals are never broadcast over the public airways. Ever. This has always been a sticky part for the ever growing FCC. They have always been annoyed that they could not control us. Standards and Practices deals with ethical standards. I work for Engineering, and we deal with technical standards.

FredThompson
03-22-2004, 08:40 PM
Ah, ok, I misunderstood your post and my thinking was too fuzzy. Reading it again, it's obvious what I saw is not what you typed. Oops. I apologize for the misunderstanding.

The FCC also dictates the decoded format, does it not? There has to be some regulatory outfit which enforces the technical format of the output, correct?

SR712
03-22-2004, 08:52 PM
I'm can't speak for DTV, but in our case, we encode (read: squeeze, haha) 3-6 different discrete signals onto one transponder. We used to carry just one analog signal on one transponder. Now, we encode several digitally. We actually decide how to encode, and what manufacturer's hardware to use. We pay for the decode hardware at the headend, or in this case, DTV. I don't know of any reg agency that would handle that. Its our business that it gets encoded and decoded properly. It wouldn't make much economic sense, otherwise, right? Why have a product noone can use? Plus, Its all really just data when its in the stream. Not much to regulate there. I guess it all comes down to- if the final customer is satisfied with the components of the signal, then it is good... and we can go home. HaHa.

I doubt anyone has much say over DTV's methods. The only way anyone would need to is if they were sharing a bird with others, but they own their own. They came up with their own mpeg format themselves. It was called mpeg 1 1/2 at the time. They are a self contained system, so it would not behove them to screw up the seperate signals.

BTW, you are correct. Line 21 is the standard. It would be silly of anyone to do otherwise. We do fill up lines 19 and 20 with lots of other stuff, though, including timecode.:D Can't do too much at 9600 baud, though.

FredThompson
03-22-2004, 09:40 PM
Is there a way to find out what all that extra stuff is in TLC broadcasts like the one the screenshot above came from?

PBS used to do some push data on their channels, news and such. I wonder if that is still used or if something like that goes over the DirecTV channels.

SR712
03-22-2004, 10:35 PM
I'm sure DTV broadcasts all that is given them. They probably just put the signal through a common frame sync, so that the streams will be easier to encode en mass. I don't know of a way to find out about individual networks, except maybe writing their engineering dept and ask. Most is usually vertical interval timecode. The "ON" bits, as little white boxes or lines, will have a rhythm to it as you watch it. Other data won't. Some videographers will put the timecode on the wrong or multiple lines in the raw footage, and this is transfered sometimes when you edit it and the playback deck is set up wrong. It never gets blanked out by the time it hits air, so its still there. When one edits, you are supposed to view in "underscan" mode, so you can see all that is happening in the entire visable raster. My monitors at home are set up that way. Seems natural to me, haha. Then there is "safe action" area, 5% in from the edges. Then there is "safe title" area, another 5% in from that. Inside that area is where you are guaranteed that titles will definately be seen on a home set.

FredThompson
03-22-2004, 11:06 PM
Then there is "safe action" area, 5% in from the edges. Then there is "safe title" area, another 5% in from that. Inside that area is where you are guaranteed that titles will definately be seen on a home set.Important note for DVD menu and subtitle design...

5318008
03-23-2004, 11:09 PM
All this arguing over Closed Captions and it turns out what we're seeing is probably not CC at all!

Take a look at line21.jpg attached below. It's an example of line 21 CC data. Note the seven white dashes on the left. They form what's called the 'clock run-in'. They're there all the time and never change.

Now look at line22.jpg. That's what all the lines I've seen on my tystreams look like - one long dash followed by a short one. That doesn't match the clock run-in. It's not line 21.

Now, all of you who are seeing lines need to take another look at them and see if they match the CC signature. My guess is that 99% of the time they won't.

So, if it isn't line 21, what is it? My best guess would be Nielsen's "automated measurement of lineup" mentioned here. (http://groups.google.com/groups?selm=a9vt04%246lc5b%241%40ID-39509.news.dfncis.de) This theory is supported by the fact that of all my tystreams that came from premium channels, not a single one has any white lines whatsoever. Nielsen data isn't of much use if you're not airing any commercials.

FredThompson
03-23-2004, 11:49 PM
Take a look at line21.jpg attached below. It's an example of line 21 CC data. Note the seven white dashes on the left. They form what's called the 'clock run-in'. They're there all the time and never change.Capture from Fox News and CNN to see different examples. They have CC but not the 7 white dashes as you show. There is a British standard which is similar to line 21. I don't remember the details but it may be some shows will have both. The sample above from TLC's Rides show has a lot more than one line of CC data. Maybe some of it is the interactive button stuff.

5318008
03-24-2004, 12:54 AM
Capture from Fox News and CNN to see different examples. They have CC but not the 7 white dashes as you show. There is a British standard which is similar to line 21. I don't remember the details but it may be some shows will have both. The sample above from TLC's Rides show has a lot more than one line of CC data. Maybe some of it is the interactive button stuff.

I've been flipping through the channels (I'm using dscaler with the vertical delay adjusted so I can see the VBI in realtime) and TLC seems to be the only channel with all that extra data. The thing is, all that stuff is actually in the active picture area, not the VBI. If TLC were broadcasting OTA, they'd need permission from the FCC to do that.

The point I'm trying to make here is that what we're seeing in the video frame does not include any part of the VBI. The capture hardware doesn't actually start capturing video until line 22. The FCC themselves define the start of the active picture area to be line 22 (had a link but it's late and I don't feel like digging it up), and all these white lines are below line 21. Thus, they're part of the active picture area. We're seeing this stuff because technically it's part of the image!

maximus315
12-27-2004, 01:25 PM
Are these white lines version specific? I have been using 3.1 and extracted video with no problems and no white lines. I just upgraded to 4.0 and now the white lines are showing there on extracted video.

vanshan
01-12-2005, 10:59 AM
So....do these white lines show up on the TV or not. Just read through this post in its entirety but still unsure if I should continue to research these white lines (which is showing up in all of my mpegs playing on my PC). If these lines don't show up on the TV, then that's fine with me as this is the only importance to me. If they do, then I will need to further reseach this as I do not want to see these when I plal the movie on my TV.

sanderton
01-12-2005, 11:42 AM
If played back ona TV, they will be in the overscan area, so will not be visible.

vanshan
01-12-2005, 03:45 PM
Thanks sanderton. Can't wait until I get home and put the movie on DVD and test on my TV. I have been reluctant to do so until I found out how get rid of the white static lines.


If played back ona TV, they will be in the overscan area, so will not be visible.

vanshan
01-13-2005, 03:14 PM
You were right. Although the white lines show on PC with various tools, they do not show up on the TV when playing the resulting DVD. Awesome!

Jeff D
05-17-2005, 05:11 PM
I stumbled across this thread linked by another CC garbage thread.

I need to nit-pick this...

The FTC requires closed caption data to be encoded in vertical line 21 of TV broadcasts.
This is not true FTC has nothing to do with it. FCC I assume... =)
There are specific rules as to what DOES need CC data. Primetime is a classic example of when you need the data, but not always. PBS for example doesn't have to have CC data on ANY broadcasts. Non-primetime TV is exempt too . The FCC tried to be pretty clear on this, but it's still pretty mucky. The networks really try to support this as it really helps them out.




I'd too really love to see how jmcclain faired in the "clean up" the video files. Cracks me up... sure go ahead and use mcpoodles tool, you'll even save a few K off your mpeg size, but... ain't going to do anything more.



You're in the classic position of knowing enough to be dangerous but you're discounting what has been explained to you.
Too true, knowledge isn't always a good thing! ;)

FredThompson
05-17-2005, 06:31 PM
Oops, FCC it is.

The "best" option, IMNSHO, is a simple subpicture overlay with not content. Voila, no corrupt junk and no re-encoding.

Oh....that's such an obvious idea that maybe it could be added to TyTool.