Compression

[DamonKelly]

I'm posting this to the VideoStudio and DVD Workshop forums, since the subject may overlap.
My apologies in advance for cross posting.

I have a project to burn to DVD.
The source is a Panasonic DVD/HD recorder, from cable TV.

Video:
PAL 25fps
704x576
MPG2 encoding 9578 Kbps (I assume VBR)

Audio:
Dolby AC3
56 Kbps, 48000 Hz, 2 channels

Quality is good, but not excellent. Better than off-the-ether, but not as good as a real DVD.

Of course, there's too much data for a single layer DVD-R! About 5.9GB, in fact.

Should I:
1. reduce the resolution to 352x576 at the same bit rate - giving me 2x the capacity

or

2. burn to hard disk and use DVD Shrink to compress to 4.7GB

I don't know how DVD Shrink works, although I've had some good results.

Does anyone have any tips on deciding?

All else being equal, is DVD Shrink's compression better than lower resolution for "ordinary" broadcast source material?
Is a higher bit rate more important?

Thanks, and cheers,
Damon

[GeorgeW]

My 2 cents:

Should I:
1. reduce the resolution to 352x576 at the same bit rate - giving me 2x the capacity

Reducing the resolution to Half D1 at the same bitrate will not give you 2x the capacity. It will be the same size as it is now. To reduce the file size, you have to lower your bitrates

2. burn to hard disk and use DVD Shrink to compress to 4.7GB

This is the option I would take --- DVD Shrink does an excellent job at this (imho) -- it's not just a re-encode at a lower bitrate, it re-uses part of the original encoding, and compresses other eligible parts (DCT-Domain Transcoding)

Notes:
-is your audio really only 56kbps?
-if you find you must re-encode, figure out how long the entire video is, and use a bitrate calculator like the one here:
Bitrate Calculator