Effects of resolution and bitrates.....

[Jimmy TwoTimes]

Made plenty of standard VCD's in the past but I've finally bought a standalone DVD player that can handle XVCD.

Can anyone tell me what effects changing the bitrate and resolution will have on the file sizes and also on the length of time Tmpgenc will take to encode non standard VCD...?

I'll probably encode using CBR as I'm not too clued up on working out VBR ( ) but I just want to create nicer looking VCD's than the standard 352x288 1150kbps spread over no more than 2 cd-r's.....

Cheers

[Craig Tucker]

Resolution has no effect on filesize it is all down to bitrate. Use a bitrate calculator to determine your filesize for the given bitrate and duration of a video.

Increasing the resolution will not increase the filesize but if you do not have enough bitrate allocated for a higher resolution the picture will look worse. If you want to increase the resolution you will generally need to increase the bitrate to maintain the same quality picture.

[Jimmy TwoTimes]

Thanks Craig, is there anyway of determining what bitrate is needed to make an increased resolution look good?

Also does this site contain a tutorial that will explain the effects of different types of encoding i.e CBR, VBR, CQ...?

Cheers

[Craig Tucker]

The best way to determine the bitrate you wish to use is to encode a short piece of video (perferably with a bit of action) and see if the resulting encode is acceptable to you.

CBR is constant bitrate, so the bitrate will remain at the specified level (approx) for the duration of the encoding process.

VBR is variable bitrate, where you specify a minimum, maximum and average. The higher bitrates are allocated where they are needed most (high action scenes) and the lower bitrates where there is very little action. So for the same size file an encode with VBR will allocate more bitrate to high action scenes so these should look better than those scenes using CBR, providing the CBR and average VBR bitrate is not so high that that any effect of VBR is not noticable.

CQ stand for constant quality and so the bitrate will vary depending on how much is required to maintain a set quality level. It is thus very difficult to predict the resulting filesize using the CQ method.

Reading this link may also help you.

http://www.tecoltd.com/enctest/concepts.htm

[Jimmy TwoTimes]

Thx again Craig.

[Craig Tucker]

No problems 8)

[hitechjunkie]

there are also a lot of guides available here which will walk you thru creating a VBR XVCD. in many cases, you will be able to get the entire movie on one 80min CD-R using VBR (i prefer TMPGEnc's CQ_VBR) at standard VCD rez.

if you wanna see a really big improvement in video quality, start with a rez of 352x576, a videobitrate of about 2400kbps (CBR is fine if you don't wanna explore VBR yet) and tweak down ur audio to 128kbps. if ur standalone can play this, you will immediately see the difference.

if u have the time, test different rez (480x576, 640x576, 720x576) and different videobitrates on ur standalone so that you know it's XVCD limits (some standalones can handle 3500kbps videobitrates, others choke beyond 2500kbps). keep at it until you find what's "acceptable to you".

[Jimmy TwoTimes]

Thx to you too Hitech...

Will experiment.