Help with CVD authoring

[tpham]

Hi all,

I've just in the last couple of days come across CVD and have also found some settings that claim to produce excellent quality CVD. My understanding is that CVDs are just SVCDs but are resized differently CVD (352 x 480/576) instead of SVCD (480 x 480/576) and therefore produce better quality video than SVCD. (You may say why not try XSVCD instead of CVD since XSVCD is better. I've tried to produce XSVCD but my dvd player doesn't seem to function too well with this format. The video quality if quite good however, the audio is shocking. Hence, I am looking into CVD.) Back to my orignal problem, I've been using D2S for some time now to produce SVCD, so last night I decided to try my luck and encode a CVD. The end result works perfect on the computer, however, in my dvd player it fail to play. It just loads the video and just hangs (no sound at all and the video is blocky). I have (3) questions;

1. Is my understanding of CVD correct that it is just SVCD but resized differently (352 x 480/576)?
2. Can I use D2S to product CVD encoded as SVCD, mount it as SVCD using Demon and burn the image as SVCD using Nero?
3. If my dvd player can play SVCD should it then play CVD encoded as SVCD or do I need a player that supports CVD?

Please help I am very confused....

[Kika]

1. Yes
2. Never tried this, guess it will work
3. Most Players will play CVDs, but not all of them, you have to try out.

Oh, and the Half-D1-Format (the correct Name of 352x480/576) does not provide better quality compared to SVCD. You will see a loss in sharpness. But it's better for interlaced encoding on low Bitrates. You can use this Format to prevent blockyness. And: Half-D1 is a Standard-Format on DVDs, so you can put this on DVD, and all Players will play it (not all Players will play SVCD-Format on DVD correctly).

[eugen]

OK, having some experience with SVCD conversing, I also want to try it with CVD, taking into account that from the quality/bitrate point of view CVD is in between SVCD and VCD. Both svcd-settings.ini and vcd-settings.ini files present at the D2S folder. Then the very simple initial question - HOW to do it with D2S into CVD resolution?

[jsoto]

Go to Misc tab, change DVD2SVCD level to Advance. Then, go to frameserver tab and change Resize to CVD

BTW, I never tried this, but I hope it works (D2S is fantastic!)

Cheers

[tpham]

Thanks guys for your answers...however I am still confused. What I don't understand, and I am assuming this to be true, is that when encoding CVD as a SVCD or just simply encoding as a SVCD both header information is the same. Meaning it will contain SVCD information, where the only different is the actual size of the video. Therefore, I fail to understand why than when my dvd player can play SVCD but doesn't play CVD encoded as SVCD? If anyone has experienced with this please help...thanks in advance

[eugen]

try the trick noticed in the "what's new" file to D2S113b2 about changing output settings for bbMpeg (from SVCD to VCD) - it pressed bbMpeg to do slightly other muxing and then VCDxbuild writes it as VCD. The video and audio quality remains!!! And compatibility with proper DVD palyers as well (expept some special ticks via playback - but chaptering remains).Or do what I am doing for a long time: manualy edit .bin file to change .MPG into .DAT, .SCD into .VCD (extensions) and SVCD into VCD (folders, 3 times, need to change one bit from 04 to 03) and write it down either with Nero or with BlindWrite with SAO cooked mode.

[eugen]

CVD vs SVCD - have tested the same clip with both resolutions.
CVD gives CCE267 bitrate 969 kbps (with 128 audio), SVCD - 985 (with 112 audio). To my mind sacrificing the resolution (in CVD) I could win in bitrate, so in total improve the quality of the picture. WHY it does not go so? WHY making resolution smaller I have the same (not very good) bitrate. My expectations was that making resolutions smaller (352x480 vs 480x480 - means app. 26% smaller) I could expect bitrate in CDV will be 985+25%=1231 - but it won't.

[jsoto]

Hi eugen
Not clear to me what are you asking… Are you using dvd2svcd?
If it is the case, the total bitrate only depends on CD size and movie length, because D2S try to completely fill the CDs. So, same movie, same CD size, you will have same bitrate. In your case:
CVD = 969 (video) + 128 (audio)= 1097 (total)
SVCD = 985 (video) + 112 (audio)= 1097 (total)

A completely different thing is the available bit rate “per pixel”. This is not a parameter of the encoder, but sure it affects the quality. Using the same video bitrate, it is clear that in CVD you have a higher bitrate “per pixel”, so the MPEG-2 encoder will give you a better quality (in movements, artifacts, etc). Sure it is not directly proportional in an exact mathematic formula, but if it was, given a bitrate in SVCD (i.e 985), the CVD bitrate equivalent (in terms of quality) should be 480/352 lower (that means 985*352/480=722).

I never code a SVCD under 1500 bit/s (my lowest quality), so, may be, this limit is equivalent to 1100 bit/s in CVD

Cheers

[tpham]

Thanks to everyone that responded...

I managed to get my dvd player to play CVD...works just fine...

One question though...I know that CVD is 1/2 DVD, since this is the case are we meant to only see 1/2 the screen. I don't know how to word it exactly...what I am trying to say is 1/2 the screen contains the movie while the other half contains the black border as follows (1/4 black border, 1/2 movie, 1/4 black border) - I hope this makes some sense. If this is correct than isn't this a funny way of watching a movie?

[RB]

No, no, it's just called "Half D1" because the resolution is roughly half of the normal DVD resolution.

[eugen]

Hi, jsoto.
just to inderstand. From the point of view of quality of picture what is better SVCD with 985 bitrate or CVD with 969? Ot both are bad. Other sample: now i am converting other film, it shows SVCD with 1300 averege bitrate. Is it worse to make it CVD? Other words could I improve the quality switching to CVD?

[jsoto]

Hi eugen

I believe there is not a definitive answer to your question and it depends on the amount of movement, noise on the original, which filters are you using... Anyway, if I have to choose, I believe CVD will have a better response at this bitrate, but, remember, the quality will be in your eyes...

VideoCalc recommends you different formats for different bitrates. I believe it gives a good idea about which format is "the best" to use.

http://forum.doom9.org/showthread.php?s=&threadid=48883
Thanks to Alexey for posting the URL of Win Wersion

Another point which has to be taking into account is the borders added to keep the aspect ratio. They allow to decrease the bitrate of the encoding with the same quality. That means, a 4:3 movie will need much more bitrate than a 2,35:1 with black bars (250 black lines in 576, in PAL).

jsoto