2 pass encode

[parkerjd]

Has anyone used 2 pass encode, or knows if it is good for video captured from VCR using Capture Wizard and recommended procedure in VS9 for Edit/Burn?

[2Dogs]

Two pass encoding is used with variable bitrate, and enables you to squeeze the best image quality from your video, especially when you are trying to squeeze a bit more onto a disc.

For example, you might have a 100 minute project, which you might just fit onto a single layer disc using compressed audio, and 8500kbps variable bitrate video.

Using constant bitrate, you might have to drop the bitrate down to 7000kbps to fit everything onto the disc.

The advantage of variable bitrate paradoxically increases when you have significant static content in your project - for example a slideshow. The unchanging sections can be more highly compressed (i.e. use a lower bitrate) whilst the faster moving sections can benefit from lower compression and higher bitrate.

If you use the two pass encoding option, the first pass evaluates the video content in order to efficiently allocate the bitrates to be used.

All of the above is well and good, but you say you are working with footage captured from a VCR. Many users state that for such footage, there is little benefit in going above about 6000kbps bitrate. Whether you wish to use variable bitrate then depends on how much you want to squeeze onto the disk.

If you do then choose to use variable bitrate, using two pass encoding may give you slightly improved image quality, but at the obvious expense of it taking approximately twice as long to encode.

I suggest you play around with some sample footage and decide for yourself.

Happy New Year!

[heinz-oz]

Has anyone used 2 pass encode, or knows if it is good for video captured from VCR using Capture Wizard and recommended procedure in VS9 for Edit/Burn?

Ooopsss, should have read more precisely, had to remove my original reply because it was irrelevant after I re-read the OP.

Dual pass is advantageous, as already pointed out in the previous post, if you have a portion of your video with fast motion and another with almost static motion. Using a high enough constant bitrate to cater for the fast motion sequences will suffice if you have a short movie only. No dual pass required. If your video gets too big in size to fit on a SL DVD, you can use dual pass variable bitrate to encode the static areas with a higher compression. The resultant file is smaller then.

In summary: Dual pass VBR will give you a high quality DVD at smaller file size than single pass CBR. There is no point in using VBR with single pass since the program would not know where to increase compression and where to lower it. Only dual pass with VBR will result in smaller file sizes at equal quality to CBR with the same bitrate.

[daniel]

There is no point in using VBR with single pass since the program would not know where to increase compression and where to lower it. Only dual pass with VBR will result in smaller file sizes at equal quality to CBR with the same bitrate.

:-)

Unless it's so obvious that single pass can effectively do it as pre-VS9 versions have shown. Slide shows as per 2Dogs answer is a case in point.
Talk shows are also very widely smaller with VBR single, with a speaker on a static background.
Multiple passes have two benefits, size is even smaller (not very much), and quality is even better (at places).
And one cost, double the time...

Commercial DVDs are nearly perfect while sometimes down to 4MB/S, but THEY use hardware encoders with 12-24 passes. The rest of us will have to wait for more than quad-cores CPU for that.

CBR on the other side is as good as it gets... if you have the needed space on the disc.