CQ w/DVDShrink vs VBR?

[rkr1958]

I encoded 2 hours & 15 minutes of source (captured) material (AVI Huffyuv) to MPEG-2 and authored using two different approaches. I used TMPGEnc Plus for encoding and TMPGEnc DVDAuthor w/AC3 plug-in. for authoring in both.

1) TMPGEnc (video only) two-pass VBR w/2000-min, 4000-ave & 8000-max kbps. 720x480 Resolution (NTSC). This method took approximately 18 to 24 hours to encode. Authored with TMPGEnc DVDAuthor (audio encoded from wav to ac3). Final size 4,483,956,736 bytes. It took me (NOT the computer) 3-days.

2) TMPGEnc (video only) CQ w/default settings for NTSC DVD-quality (8000-max, ?-ave, ?-min). Total encoding time of 6 to 7 hours. After authoring (wav to ac3 audio) final size was 5,731,549,184 bytes. Then I used DVDShrink to compress to 4,680,845,312 bytes. This method took me 1-day.

Just curious, any thoughts on which method should yeild better quality?

I understand VBR and CBR but I still don't grasp what CQ is (even though I've read several posts on it). The closest I've come to understanding what it is a one-pass VBR? Is this correct? If you get an oversize Video_TS file and Shrink it with DVDShrink should the quality be the same as if you determined maximum average bit rate and did a 2-pass VBR encode? While klugely, CQ w/Shrink appears to be much faster.

[bugster]

You are correct in saying that TmpGenc's CQ mode is a form of 1-pass VBR. Quality wise it is very good, and much faster than 2-pass VBR. IMO, the quality of CQ is often as good as and sometimes better than 2-pass VBR. The main drawback of VBR is the unpredictable size of the final mpeg.

In theory, using 2-pass VBR and maxing out the available disk space on a DVDr should give better quality than using CQ to produce an oversize mpeg and then using DVD shrink to bring it down to size. However, in practice, unless you are pushing the limits of a DVDr with respect to movie length (say 2 1/2 to 3 hours as the max) then it is unlikley that the difference would be very noticeable, if at all. For longer movies, stick to 2-pass VBR.

BTW, 18hrs or more to encode 2h 15 to DVD seems rather a long time given that you have a 2.6Ghz P4. Try reducing the Motion search precision or, if using the noise reduction filter in TmpGenc, look into using vdub to filter and framserve to TmpGenc, it should save you some time.

[rkr1958]

BTW, 18hrs or more to encode 2h 15 to DVD seems rather a long time given that you have a 2.6Ghz P4. Try reducing the Motion search precision or, if using the noise reduction filter in TmpGenc, look into using vdub to filter and framserve to TmpGenc, it should save you some time.

I have Motion Search Precision set to "Highest Quality (very slow)". Is that why it's taking so long? What do you recommend reducing it to? And, what kind of quality hit (if any) should I expect?

Thanks.

[fritzi93]

My opinion is set motion search precision to normal. In my experience, it'll go at least twice as fast and the quality difference is (usually) undetectable. That's if your source file is good. When you get a problematic one, you'll throw everything you got at it, trying to make it passable. :P But cut out a couple short clips and try it yourself.

[bugster]

My opinion is set motion search precision to normal. In my experience, it'll go at least twice as fast and the quality difference is (usually) undetectable.

Ditto.