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I have HDV video that I want to burn onto DVDs and share. For my final run, I'm willing to spend a bit of time doing the render if it will give a noticeable difference to those who play it.

Anyone have comments on how much you gain going to greater than the 70% default on the mpeg quality slider?

Also, how much quality does a 2 pass encode buy you?

Do these quality differences only show up if you play the standard DVD on a HD TV?

Thanks.

First, HDV uses a constant bitrate (CBR) of 25 Mbps. Two pass encode is meant for Variable Bitrate (VBR) where the first pass examines the video and works out the best way of encoding in the second pass to get maximum quality. In other words, two pass encode does not work with CBR.

As for the quality slider, I imagine quite a few people use it. In fact, it is a quality/time slider meant to represent a balance between the end quality and the time taken to achieve it. In other words, the default 70% setting is supposed to represent a happy balance between good quality and an acceptable rendering time. I personally have always left it at that. The few times I have experimented with it, I have not been able to detect any significant improvement in quality to warrant the extra time taken to produce it (and I am a very patient person, believe me).

But to be fair, some users swear by it, and claim there is a noticeable improvement in quality by using it. I often wonder, though, whether they are using it in conjunction with VBR and two pass encode, when the end result can indeed be noticeably better...

But that's just my personal opinion. You have to try it all yourself and see how you find the results.

Two pass encode is meant for Variable Bitrate (VBR) where the first pass examines the video and works out the best way of encoding in the second pass to get maximum quality. In other words, two pass encode does not work with CBR.

The final output would be a standard DVD with VBR 8000 (depending on length of video). Does 2 pass encoding help this?
Or, would it only help if the DVD were VBR 4000 (a 2 hour dvd)?

ABe wrote:

Two pass encode is meant for Variable Bitrate (VBR) where the first pass examines the video and works out the best way of encoding in the second pass to get maximum quality. In other words, two pass encode does not work with CBR.

The final output would be a standard DVD with VBR 8000 (depending on length of video). Does 2 pass encoding help this?
Or, would it only help if the DVD were VBR 4000 (a 2 hour dvd)?

Yes on both, however the quality difference may not be that noticeable with the higher bitrate. It certainly does not work with CBR, as it needs 1 pass to analyze the clips. In my opinion, 2-pass is best used for projects that have fast motion and still, or very slow motion. The program then uses a higher bitrate for the fast motion parts, and a very low bitrate for the slower or still parts. If the motion is fairly consistent over the entire project than 2-pass encode would not be very beneficial, IMHO..

Thanks for the insight.

I recently did a quick test rendering a video file from HDV (mpeg-ts) to standard DVD at VBR 8000. With the quality slider on 70% and 100%, there was no difference in render times. For this clip, 3 minutes.

When I checked the 2 pass box, the render times doubled (again the same for 70% and 100%). Approx 6 minutes.

When I added a pan and zoom video filter to the 2 pass render (make VS do some work...), the time was 50% more, or 9 minutes for the clip.

The clip is of a speaker at a funeral, so there isn't a lot of movement. At first glance, I wasn't able to tell much quality difference on the computer. If I get time, I'll burn a DVD and play them on my HDTV and see.

Ken Berry wrote:First, HDV uses a constant bitrate (CBR) of 25 Mbps. Two pass encode is meant for Variable Bitrate (VBR) where the first pass examines the video and works out the best way of encoding in the second pass to get maximum quality. In other words, two pass encode does not work with CBR.

Ken, I am a bit confused now...Do you mean that HDV footage, because it is CBR, cannot be used for creating a two pass encoded VBR DVD? I thought the 2pass VBR DVD creation process interprets the DVD encoded image data whitout taking into account the original (HDV) CBR datarate.

Hi

I don¡¦t think Ken meant that, Two pass encoding is used with Variable bit rate.

You can convert Constant to Variable and use two pass.

But using a bit rate of 8000 and you might as well use constant.

Variable bit rate is used to reduce the file size allowing you to fit more footage to a disc.
With the advantage of maintaining quality.

8000kbps at 60 minutes will fit to a disc, (4.3Gb) so if your video is shorter than 60 minutes use constant bit rate.

At least that¡¦s my opinion.

So how long is your video?