Q: creating dvd compliant cvds

[zulu]

hi everybody!

in order to be able to still watch my movies when the next-gen dvd hardware will be released (which will be downward compatible to the current dvd),
i want to assure that the movies i encode are _dvd compliant_.
i read one can achieve this by creating a cvd by using dvd2svd w/ CCE.

in other words, my goal is to create cvds with dvd compiliant mpeg2 streams _now_ and reauthor them to dvds _in the future_ , when dvd burnes are more affordable (without re-encoding of course).

what i know so far is that you have to resize the video to 352x480/576 (legit half-rez dvd resolution), the audio must not be downsampled.

but there are also a few questions left bothering me:

- what kind of bitrate is allowed - (multipass) vbr or only cbr?
- is the max. cvd bitate the same as for svcd?
- are there specific bbMPEG setting i have to set (program stream
type -> mpeg2, svcd or DVD; pack options; startup delay;
timestamps etc..)?

- GOP settings:
i've heard the gop length has to be 15 for pal movies. where to
set this in dvd2svcd?
over @ vcdhelp.com someone claims you have to force CCE to close
all gops. is this true?

- in a dvd2svd created .ecl file i saw that the "dvd" key was set to 0 (false). i assume this is the setting for the "dvd comliant" checkbox in cce.
it's set to 0, so does that mean the stream is not dvd compatible?

- is there anything else i have to take into account to avoid future trouble with dvd authoring software?


TIA,

zulu

[gerti67]

Hi zulu,

as I don't have a DVD burner myself, I can only give you a theoretical answer yet. ;)

- DVD allows bitrates up to 9800 kbit/s so this is not a problem - you have to make sure your DVD player can play those bitrates - some are known to play fine up to 4500 kbit/s. But you have to test this with your standalone player.

- And the CVD bitrate is the same as for SVCD because the resolution doesn't matter here - when using the CVD resolution there are more bits allocated to certain blocks than with the SVCD resolution because there are less blocks to be considered with the CVD resoluzion - but the overall bitrate is the same for both only the allocation is different.

- The bbMPEG settings are not that important, just set them to the SVCD specs because you can always demux your MPEGs afterwards and your DVD authoring software should then remux or proces them properly.

- The GOP Settings a far more important as many DVD authoring apps only accept GOP length of 12 or 15 frames but this depends on the authoring app - for PAL a GOP length of 12 should work with any authoring app. You can set it by changing the "M/N" value in the "Advanced settings" of the "Encoder" tab from "5" to "4" for CCE. You have to make sure to set the "DVD2SVCD level" to "Advanced" also in "Misc." tab to have access to this settings.
And with the "Closed GOPs" it's the same as with the GOP length - it depends on the authoring app but you are on the safe side when selecting "Close all GOPs" in CCE's "Advanced settings" within the "Encoder" tab also.

- The "DVD compliant" setting for CCE has not to be set as this is only a "quick switch" to let CCE resize all the input to 720x576 - the DVD full resolution. So in your case it would override your CVD resolution setting.

- From my knowledge these were the most important settings to be set - at least those that wouldn't require a later re-encoding of the video stream which would result in a degraded quality. All other settings shouldn't be a problem for later DVD authoring.

Hope this helps,
Gerti