tmpgenc plus: 2 pass vs. cq vbr

[EAO]

I'm still a newbie when it comes to finding the minimum action settings that I can tolerate when creating an mpeg 2 from avi for dvd.

I have made a 'discovery' that I think others may find useful.

I was converting a two hour fifteen minute commercial vhs. Due to resolution of the original source I capture at full but convert to mpeg using half d1. I didn't feel like wasting a full DVD on just a vhs capture and decided to use 2200 mb. Using the tmpgenc wizard I saw that I would get a max bitrate of about 2600. (I'm not certain about the numbers anymore, but I know they're close.)

I usually use 2 pass vbr. But even when converting half d1, I like to use 5000 and 2500 bitrates. Since this was so low (to me) I decided to use cq vbr. I was absolutely blown away with the result. I'm already used to vhs conversions 'looking better' than the original, but three new things impressed me.

1. This was a Dr. Who tape and if you've seen it before then you know the opening sequence has a moving tunnel effect that always pixelates at low bitrate. Well this scene was perfect to my eyes.

2. The other benefit was on panned scenes - where the camera moved accross the scene - I would see a slight blurring, even on a full d1 with high bitrates. Well...this was incredible. No blurring at all.

3. And the time it took to convert. It usually takes me 3 hours to convert 45 minutes on full d1 using 2 pass vbr. This two hour plus conversion only took me 2 hours and 25 minutes. (I know one was full d1 and the other was half d1 - but I find it hard to believe I won't experience a time savings when I try cq vbr on full d1.)

Anyway, I thought I would share. Anyone else have any experiences with this setting?

[poerschr]

yea, I am always glad to talk with another Doctor Who enthusiast. I too have spent many a day encoding Doctor Who. I am looking forward to the new series.....

However, you find is a very well established fact with TMGenc. Hands down CQ is the way to go, it is some kind of bug in the program. The only problem comes with predicting file sizes.

[fritzi93]

That's exactly what I do, half D1 CQ, made a template for it. Seems to me it yields the best results in TMPGEnc for an AVI or VHS capture. Pretty fast too, as TMPGEnc goes. It's good to hear someone else thinks so too. Yeah, the only drawback is unpredictable file size. With practice, your guesses as to CQ level will get better, though.

[EAO]

About the new Dr. Who....

Will it be shown in the U.S.?

[johns0]

I`ve done quite a few cq encodes and found a rough file prediction for the different file types,for example cq 80 for 1/2 d1 for 120 min for widescreen with pulldown is around 1200mb and full screen with pulldown is around 1600mb and full screen in 29.97 will get about 2 gigs,divx and xvid files usually will give you even smaller file sizes.

[poerschr]

@EAO
maybe on the Sci-Fi channel or BBC America...but it has not been confirmed yet..we might have to wait some time to see the series...

[lordsmurf]

CQ is often seen as better than 2-pass. The creator supposedly spent more time on CQ mode.

[EAO]

Well now that I'm home from work I have a few...

1. I want to clarify that I'm using cq_vbr not just cq.

With what Lordsmurf mentioned would you suppose that the final product would be the same (better) if I just went to the cq setting? At this point I'm very happy with the quality, but - like everyone - I wouldn't mind better.

2. Actually it was max and min bitrate of 2400... and my quality was set to 100. Motion search was slow. DC precision was 10.

Would that mean I was only in cq mode because my min and max were the same? I think yes, but I'm not sure because the program was analysing for about 20 minutes before it started to convert.

3. Thanks for the info... esp about Dr. Who. Don't know if you've seen it but the tape was called Shada. It was an 'unfinished' episode. Are you familiar with it?

[lordsmurf]

I use CQ_VBR

[poerschr]

@EAO
Yup, I have the tape of Shada, it is a shame that they never finished it..looked like a great episode to me...