two pass encode

[dmz]

I read somewhere here that two pass encode would be a good idea. I tried it last night on a number of my projects. The second pass of every project failed with a pop-up saying something like "could not encode the video". Am I doomed to never being able to use this option? Or just unlucky? I tried it with eight completely different projects from different source avis.

[heinz-oz]

I use 2 pass encoding on almost every project I do because my footage is a mix of relatively calm action with fast moving sequences in between. Dual pass gives me a smaller file size while retaining good quality.

If your projects are around 1 hour in length, a single pass with a high CBR is going to be sufficient. Dual pass VBR would only leave more free room on the disk.

What were the exact settings you used for the mpeg encoding?

[GeorgeW]

The second pass of every project failed with a pop-up saying something like "could not encode the video".

Does it encode with a Single Pass Perhaps there's something strange in your source .avi's -- what are the properties of all your source .avi's

Dual pass gives me a smaller file size while retaining good quality.

I think the smaller files sizes are not due to using 2-pass encoding -- it's more related to changing from CBR to VBR (and the way Ulead is using the entered bitrate as a MAXIMUM bitrate setting during the encoding process).

Regards,
George

[dmz]

I use 2 pass encoding on almost every project I do because my footage is a mix of relatively calm action with fast moving sequences in between. Dual pass gives me a smaller file size while retaining good quality.

If your projects are around 1 hour in length, a single pass with a high CBR is going to be sufficient. Dual pass VBR would only leave more free room on the disk.

What were the exact settings you used for the mpeg encoding?

My input was the standard DV format and my output was PAL 16:9 vbr 6000 with mpeg audio.
The single pass works every time. And I guess I cant use CBR cause I need to fit about 1:30 on a single DVD.

[heinz-oz]

A CBR of around 6800 with AC 3 sound at 256 kbps would also fit a 1 hour 30 minute project.

VBR really only comes into being with dual pass. The encoder evaluates the video in the first pass to determine the degree of movement and where a lower kbps can be used. It will use up to the maximum bitrate when needed (fast movement) and a lower bitrate where there is little movement. In single pass the program would not be able to know where to increase or decrease the bitrate.

[sjj1805]

Please view:
What bit rate settings should I use?

Normally you use CBR (Constant bit rate) but if you find that your completed project is slightly too large to fit onto your DVD disc then you can reduce the file size slightly by using VBR (Variable bit rate)

[dmz]

A CBR of around 6800 with AC 3 sound at 256 kbps would also fit a 1 hour 30 minute project.

VBR really only comes into being with dual pass.

Firstly, is the sound type very critical? Ive always used mpeg audio cause I thought it was the most compatible.
Second, if VBR is only for dual pass, and I can never seem to use dual pass, then I should only ever use CBR?

[Trevor Andrew]

Hi

I use CBR for all my work.

We cannot really compare 6000 constant with 6000 variable.

Firstly the ¡¥constant rate¡¦ is referring to the average rate whilst the ¡¥variable¡¦ is referring to the maximum rate.

So if we encode using constant then all frames use 6000 (or there about)

If we encode at 6000 variable, Afaik None will be coded using 6000. (6000 is the Max) All will be encoded lower than 6000.

Yes the highest used may well be 5900. But this will not produce the same quality as 6000 CBR.
The average bit rate being lower will produce a smaller file size.

Using variable instead of constant (using the same bit rate) does not produce a better quality, just a smaller file size.

That¡¦s the way I understand it.

Regards

Trevor

[GeorgeW]

Hi

I use CBR for all my work.

We cannot really compare 6000 constant with 6000 variable.

Firstly the ¡¥constant rate¡¦ is referring to the average rate whilst the ¡¥variable¡¦ is referring to the maximum rate.

So if we encode using constant then all frames use 6000 (or there about)

If we encode at 6000 variable, Afaik None will be coded using 6000. (6000 is the Max) All will be encoded lower than 6000.

Yes the highest used may well be 5900. But this will not produce the same quality as 6000 CBR.
The average bit rate being lower will produce a smaller file size.

Using variable instead of constant (using the same bit rate) does not produce a better quality, just a smaller file size.

That¡¦s the way I understand it.

Regards

Trevor

That's correct -- VBR does not automatically mean smaller file sizes (outside of Ulead). It's just the way Ulead implements VBR that this is generally true -- because Ulead only allows you to enter one bitrate, it is set to the MAXIMUM bitrate. Normally you would specify Minimum/Average/Maximum for VBR encoding. In fact, VBR using the same AVERAGE bitrate as CBR would be about the same size.

NOTE 1: some Ulead software will let you specify min/avg/max bitrates (either out-of-the box, or by tweaking files -- but I wouldn't recommend the tweaks).

NOTE 2: the problem with VBR is you might get bitrate "spikes" -- meaning the bitrate at certain points spike above the stated MAX bitrate. So if you are using a high VBR, you might get spikes above the DVD Spec limit -- causing "stutter" or "stickiness" during playback in some DVD Players...

Regards,
George