necessary bitrates for 3 hour mpeg captures??

[kenmasters83]

i currently use 720x480 as the my main capture resolution for 2 hour movies.

now i want to start capturing 3 hour movies i know i am going to have to use low resolution 352x240 res in order to squeeze that many hours on there.

but what bitrate should i use for low resolution captures??

i am using tmpgenc plus and tmpgenc dvd author as the authoring program i want the quality to be the best it can be too.

is there a such thing as too high a bit rate for low resolution dvd recordings?

[jimmalenko]

There comes a point where there's no inherent increase in the quality of captures, which varies from around 2000kbps for 352 X 288/240 to about 4000kbps for 352 X 576/480 to about 8000kbps for 720 X 576/480.

In any case, a Bitrate Calculator will assist you no end in getting your bitrate correct first time. Simply plug in the amount of time you wish to capture, choose what your audio will be in the end, and it tells you what video bitrate you should use.

The following is the roughest of rough guides that I use (and is based on either captured or downloaded material that I re-encode, but for direct MPEG capturing is still semi-relevant):

(where ave is the value the bitrate calculator gives you)

If ave is < 1000kbps, I'd use 352 * 240/288 2-Pass VBR (min 100 ave ave max 2000)
If ave is > 1000kbps & < 2000, I'd use 352 * 240/288 ave CBR
If ave is > 2000kbps & < 4000, I'd use 352 * 480/576 2-Pass VBR (min 1000 ave ave max 6000)
If ave is > 4000kbps & < 6000, I'd use 352 * 480/576 ave CBR
If ave is > 6000kbps & < 7500, I'd use 720 * 480/576 2-Pass VBR (min 1000 ave ave max 9000)
If ave is > 7500kbps, I'd use 720 * 480/576 ave CBR

My personal preference is to capture to AVI using very good settings (DV-AVI format) and then re-encode using filters, but if you're after a "quick n dirty" MPEG capture, that's your choice

More info:
http://www.digitalfaq.com/capture/software-resolution.htm
http://www.digitalfaq.com/capture/avivsmpeg.htm

[sacajaweeda]

352x480 @ 3000 for 3 hours should be okay for most stuff as long as it isn't really busy high action stuff.