[bug] Half-D1 and 16:9

[Boulder]

I just noticed that DVD-RB will allow using half-D1 resolution and encoding as 16:9. According to the specs, this is not allowed; 352x480/576 can only be encoded as 4:3.

jdobbs, could you fix this so that there would actually be a conversion from 16:9 to letterboxed 4:3 for the half-D1 resolution?

[jdobbs]

I originally had thought to not allow it... but I have yet to have heard a report of a player that couldn't play 16:9 anamorphic in half-d1. I also couldn't actually find any official reference that forbids it (but I honestly didn't look that hard). I did notice that it is referenced as one of the anamorphic formats on the DVD Demystified FAQ.

All considered, I decided to allow it.

You wouldn't happen to have a reference to the spec that forbids it would you? This is pretty much the only "not sure about compliancy" setting allowed in Rebuilder -- and if I could find an official reference I'd probably remove it.

[Boulder]

I tried to find an official reference as well, but failed. The DVD Demystified FAQ is a bit vague, the point where anamorphic is mentioned with half-D1 discusses aspect ratio. I've just read everywhere that half-D1 + anamorphic is a no-no according to the specs.

I guess you have to pay a large amount of cash to get the detailed specs :( There might be some people on the board who know the answer, maybe those who actually work in the business themselves.

[jdobbs]

I've also seen it mentioned as not allowable in unofficial threads etc... but you know how sometimes these things get spread around.

I looked through ISO 13818 and couldn't find anything forbidding it there...

[Boulder]

Found this: http://www.mpeg.org/MPEG/DVD/Book_B/Video.html

In addition to it (possibly) not beind DVD compliant, the image quality will be better when letterboxed to a 4:3 image. The image will become very blurry when a half-D1 resolution is stretched to widescreen.

[Trahald]

scenarist doesnt allow 16:9 in half d-1 assetts so i think that may be part of the reason. i dunno if someone like sir didymus can use philips verifier to check it out. but imho, its one of those things that even if verified as out of spec, should be allowed and maybe just throw a warning. even scenarist will mux 16:9 half d-1 if you force it into doing it. the benefits of that as an option outway the small chance some player may not like it.

[jdobbs]

[Edit] Removed this post because of incorrect reference.

[jdobbs]

Ok I just found a reference in the DVD Verifier manual that lists the acceptable resolution/aspect ratio combinations. It shows 352x480 as only having a 4:3 aspect ratio. The specification quoted is DVD-3 Tab 5.4.1.1-1 and 5.4.1.2-2... I don't have access to those.

So I guess the bottom line is that if DVD Verifier says its illegal and Scenarist says it's illegal and there is a quote on MPEG.ORG that it's illegal -- it's safe to say that it's illegal.

So now the question is... do I really want to disallow it?

[Rippraff]

So now the question is... do I really want to disallow it?
IMHO no as long as it works on most of the players. But as Trahald said a warning might be a good idea.

Cu Rippraff

[scharfis_brain]

So now the question is... do I really want to disallow it?
Difficult question.
From the point of view of the DVD-Standard? Yes.

From the point of view of quality? No. Cause vertical downsizing (especially interlaced contents) will introduce new artifacts, that may irritate MPEG more than the bigger sized halfD1 anamorphic image.
Also I strongly disagree with Trahald in this point, cause anamorphic halfD1 looks better than letterboxed HalfD1. At least on CRT-TVs.

[Boulder]

Also I strongly disagree with Trahald in this point, cause anamorphic halfD1 looks better than letterboxed HalfD1. At least on CRT-TVs.
That was my suggestion ;)

Maybe there should be an option for either way of processing?

[jdobbs]

I think I'll just post a warning in the log and let the user decide if he/she wants to continue.

[Trahald]

...
Also I strongly disagree with Trahald in this point, cause anamorphic halfD1 looks better than letterboxed HalfD1. At least on CRT-TVs...

Hey i didnt say that ;).. i like half d1 (16:9 and 4:3). although recently ive tended to more try filtering and matrix tweaking over 1/2 d1.

[scharfis_brain]

whoops! I confused Boulder with Trahald.
Sorry!

[laserfan]

I think I'll just post a warning in the log and let the user decide if he/she wants to continue.This seems the most reasonable approach to me. Some of us might not care--if the backup plays on our players then we're happy. Others might fret that a player they'd buy in the future wouldn't play these discs.

[dragongodz]

Maybe there should be an option for either way of processing?
i would have to throw my vote this way if you really want to keep 16:9 half D1. that way people would have the choice to do it in spec and have no recourse to complain if they do it out of spec and have any problems. that is if they chose 16:9 half D1 and got a warning and had the option to do letterboxed 4:3 instead then they couldnt complain DVD-RB is creating bad oputput without them knowing etc.

[wmansir]

I'm a big user of Half-D1 and if given the choice I would probably continue to use it with 16:9 material, but if you want to make DVD-RB spec compliant then perhaps letterbox half-D1 should be the default with the current method being an option.

[laserfan]

Not to take this OT or anything, but since many here are interested in Half D1 I thought I should point out: I've been making these for a few years now using my standalone Tivo, and they looked great on my 41" RPTV. Since getting a 60" HDTV however, these recordings look lousy, almost unbearable to watch.

I realize that RB users are probably starting with a cleaner source, and therefore getting better results than I, but I just wanted to warn anyone here who may be interested, that once they get a bigger TV they may not be happy w/their DVDs anymore. YMMV.

I did recently make a Half D1 backup using RB Pro. I'd made a "movie-only" Full D1 backup of Spider-Man 2, and then I made a "complete with extras" disc wherein I did the feature at Half D1 and all the extras at full-quality. The "movie-only" backup was great BTW--kudos to jdobbs and to Hank for HC16.

[Sir Didymus]

Just tested what Trahald suggested yesterday...

Step 1: prepared a short asset using the following script:


#------------------
# Test file for half D1 + WS
#------------------
LoadPlugin("C:\Tools\DGMpgDec 1.4.6\DGDecode.dll")
mpeg2source("E:\test\demux\VideoFile.d2v",idct=4)
LanczosResize(352,576)
ConvertToYUY2()


Step 2: Encoded the asset with CCE, specifying to keep the resolution, and to generate a 16/9 mpeg2 file;

Step 3: Created a DVD based on the previous asset using MuxMan;

Step 4: Run the Philips Verifyer;

It is interesting to note that in step 3 above, MuxMan accepts the m2v asset (recognising it as 352x576 AND 16/9) without complaining about; also in the mux log the authoring is reported as error free.

The Verifyer is reporting a number of errors like the following:


>>> [DVD] ERROR 3360 (ref. DVD-3 Table 5.4.1.1/2-2) :
Sequence_header : illegal aspect_ratio 3 /horizontal_size 352 combination for
video sequence (0) at byte 7207401 bit 7;
PES ($E0) byte 7239732 (byte 100 of packet 3571);
byte 114 of pack 3588 (PS stream byte 7348338).


Of course the DVD playback is perfect...

In spite it seems it is probably not compliant, my vote is also to keep the possibility of producing half D1 & 16/9 rebuilds...

There is no point in totally disallowing this possibility. Since also MuxMan is not complaining in the production of such type of DVDs, I would say it would be not a mistake to allow DVD-RB doing the same...

[blutach]

I'd also keep it as an option, although from now on, I'll be using 4:3LB for 1/2 D1.

Regards

[influenza]

I do half-d1 on my extras quite a lot. I never bother to see if it's 16:9 or not . Although I know that it's not spec compliant I never had a single disc that couldn't be played on any standalone. Just as it's not spec compliant to have some forms of audio on NTSC discs, while no player will complain.

A warning would be nice to make people at least aware of this (but please make it possible to turn it off, after showing it once ;))

[mpucoder]

What the verifier is complaining about is the restriction of 16:9 to widths of 720 or 704. However most players should have no problem since it would take an extra effort to not display this properly.

[Susana]

This is an old question:

http://forum.doom9.org/showthread.php?t=95424

:)