svcd blockiness under high cbr?

[snizzles]

im having troubles with encoding and tmpgenc @ ntsc film 24fps. i use ivtc in tmpgenc to convert to 24fps. when i select preview in tmpgenc to see how my result mpg will be everything looks perfectly clear, i see no blocks or chunkiness even when i pan frame to frame. but after i encode and play on my computer/tv, some points seem blurry and distorted. especially when theres big flashes of white or sometimes when the scenes change. the setting i use under tmpgenc is cbr 2496 and a high quality setting. could the high cbr setting be causing the result video to play chunky on my tv? i cant figure it out please has anyone else experienced problems like this that can help me??

thanks again,

sean