Strange problem converting local show to mpeg2.

[jcm0320]

I have been using my Canopus ADVC 110 to capture a local televison program every weekend. It's one of those "late night horror hosts" kinds of things that is played on our local FOX channel.

Afterwards I convert the digital video to mpeg2 using TMPGEnc 4.0 Express.

The settings I use are as follows:

Video System: NTSC
Encode Mode: Prioritize Quality
Aspect Ratio: 4:3 Specs
Rate Control Mode: VBR (Average bitrate)
Audio Format: Dolby Digital
Video Size: 352x480 Locked
Average Video Bitrate: 3645.516 Kb/s
Audio Bitrate: 224 Kb/s
Maximum Bitrate: 8000 Kb/s
Minimum Bitrate: 2000 Kb/s
Pass Count: 2
Padding: No
DC Component Precision: I've tried 9 and 10. Neither makes any difference.
Display Mode: Interlace
Motion Precision Search: Highest (with error correction)

The entire program is usually 2 1/2 hours long so I know that a lot of video is being squeezed onto a DVD. That's why I choose VBR over CBR.

Now here is the part I don't understand...

(Keep in mind this is after converting the video to mpeg2 then watching it on a DVD.)

When the actual movie is playing the quality is very good. But during commercial breaks, when the hosts are talking to the viewers, the quality is not that great. At times it even seems like there is a little bit of slow down. I am never able to notice this untill after the video is converted to mpeg2.

So in my amateur opinion there could be two different reasons:

A.) The portion of the broadcast where the movie hosts are being shown could have been recorded digitally and already compressed. And if this is the case then recording it myself and re-compressing it may result in quality that isn't that great.

Or

B.) The VBR setting is not accurately assigning the correct bitrate to these segments, being that not much action is taking place when just two hosts are talking on TV.

I have noticed that when TMPG calculates the size of the output file it is way off. So I have been able to bump the average bitrate up to about 4200 Kb/s without creating a file too large. This has not helped me either.

Any ideas? And do you understand what I'm saying?

Thank you!

[redwudz]

For A and B, both may be likely. Your settings seem fine, but you could drop down the motion precision to 'high' quality and save a fair amount of encoding time with little quality loss. Have you tried different settings there? Same with component precision. Highest takes longer, but you may not gain much in the way of quality.

This guide may help you fine tune the encoder a little: http://dvd-hq.info/Compression.html