Settings for DVD compliant CVD- GOP settings and min bitrate

[bones_1284]

I know these questions have been asked before but i'm still unsure.

I want to make a CVD that can be later converted to a compliant DVD without re-encoding.

I know it should have 48kHz audio so it doesn't need to be re-encoded. But i am unsure about the GOP settings in DVD2SVCD using CCE 2.50.

Max frames per GOP needs to be 15 for PAL and 18 for NTSC right?
But there is no max frames per GOP in CCE, only GOP sequence settings
which defaults are: M=3 N/M=5
What do these values indicate?
I read they should be M=3 N/M=4 for DVD compliance but is this for PAL or NTSC?
What settings should i use for PAL and what do the M and N/M mean?
I've also read conflicting reports about whether or not closing GOPS is necessary.
It can reduce quality so i want to avoid it if a can still guarantee compliance.

Also i made a sample that looked ok at 560k video and 128k audio, not great looking but not very blocky and definitely watchable. I was actually quite suprised at the quality considering the bitrate.

Anyway i was wondering what is the lowest average bitrate that can be played on all SVCD/CVD compatible players - i know this sample would not work on all but it works on mine.
And what is the lowest average that can be played MOST players?
Also the same 2 questions for min bitrate.

I would like to keep the CVD as compatible as a CVD can be.

Thanks for any help.

[RabidDog]

8) cvd or half d1 (d1=full resolution) is a valid dvd spec. Search in here for the correct specs. I think you are pretty much there. Also closing gops reduces quality but only by 2%. Close gops for editing mainly. Also most dvd players these days are probably quite "relaxed" about the specs.
Min bitrate should be 0 butmost people stick to around 300 for safety and viewability. the lowest average would be the same, but you would be watching a v bad quality.
What about vcd or quarter d1 (352x288) this, at very low bitrates can be better than cvd (mpeg2 vbr 300,800,1200) and you could get many hours on a dvd. (this is what dvd-rw are for 8) .

[bones_1284]

But wouldn't a vcd at low bitrate be a xvcd and therefore less compatible.

Also a cvd at 352x288 would be even better quality for low bitrates wouldn't it?
But would it be less compatible again or even work because of the non-standard resolution?

The reason for asking about such low bitrates is that i was trying to squeeze 155 onto 1 cd but still be compatible and be able to be converted to dvd later (maybe not possible).

Oh yeah and thanks for your reply Rabid.

[RabidDog]

8) AFAIK half d1 and quarter D1 are valid DVD resolutions, the bitrate you use will determine what time length of video data you can store on a disk. A vcd is MPEG1 at a constant bitrate (1150) I was talking about an mpeg2 @ 352x288 and variable bitrate encoding, thus allowing a lower overall bitrate than 1150. This does work on sony dvd players. to get 155 mins on one cd is pretty much impossible, with any decent quality. Even squeezing 80mins per cd is stretching it a bit. 2 cds. or test various combos using cdrw and check if the quality is acceptable.
see www.kcvd.netguides there!

[bones_1284]

Well like i said before i have encoded a sample cvd at (0,560,2520) video and 128 audio that looked ok just not quite acceptable. I wouldn't be suprised if reducing the resolution to 352x288 would give it just enough more quality to be acceptable ...but maybe not.

Anyway i have already decided to put it on 2cds which using the same sample at the 2cd bitrate of 1200 gave dvd quality when watching it on tv. Maybe if i sat closer and had a HD tv i would notice the difference - but i don't.

[RabidDog]

Yo ! way 2 go, 2 Cds, you know it makes sense! why not experiment with the 352x288 setting and see if you like it? please report back.
imho your setting , 0 min 560 avg 2520 max would probably benefit from a higher average, say at least 1000? your settings would work well with the lower resolution ( 0,560,1200.)

[bones_1284]

The 0 min 560 avg 2520 max settings were so i could squeeze on to 1 cd.
For 2 cds i'm using 300min 1200avg 2520max.
At the 1cd bitrate, switching from svcd to cvd resolution made a big difference so using 352x288 would probably help even more but is it a supported resolution for svcd?
At the 2cd bitrate i could not notice any difference between the svcd and cvd resolution, but i chose cvd because i will be able to convert to dvd without re-encode. So for this bitrate i don't think 352x288 would help quality.
I would test this but i'm half way through encoding the 2cd rip (taken 12 hrs to do half).

your settings would work well with the lower resolution ( 0,560,1200.)

are you also suggesting i reduce max to 1200? why?