Capture with Canopus or Topfield

[zenzen1]

My Friend and I are confused about capturing quality, and so an intelligent and informed discussion on this subject would be most appreciated.

My email to my friend:
Using a Canopus ADVC-100 and capturing to AVI, the results will never look as good as digital television.
Reason:
If you captured 1 hour uncompressed, the file size would be 80 gb (roughly).
If you capture with a Canopus ADVC-100, one hour of captured
video = 15 gb, so you can see, there is some significant compression there.

Now......Encode that 80 gb uncompressed, OR that 15 gb Canopus
using the best encoder you've got and squeeze it down to 4.7 gb,
so it will fit on a blank DVD....and what do you think happens ???

My friend's reply... Using a Topfield PVR with harddrive
The Toppie captures DTV at roughly 1½ hours per DVD (4.3 GB). No compression, no loss of quality, just recording the DTV stream as comes from the tuner.

A 1 hour recording works out about 2.9 GB. So the methods used to capture 1 hour at 80 GB or even 1 hour at 15 GB are actually making the data larger than it really is. No doubt as a result of converting it from digital to analogue and back again. Obviously you would get a much better result compressing a 2.9 GB file (if you needed to) than compressing a 15 GB file (which you have to).

You would only need to encode a DTV stream if the recording time exceeded 1½ hours.

[junkmalle]

Yes, capturing the native DTV MPEG stream should give you the best quality. Is it DVD compliant though? I know many satellite feeds are at non-compliant frame sizes.