702x480 or 352x480

[slacker]

I need to pack 300 minutes of high school football footage onto a DL or 150 minutes EACH onto 2 4.7gb +Rs. In doing some 1 minute encodes of material using 704x480 (source) mpeg and 352x480 using 3500mb vbr in Vegas (Mainconcept), I am having a tough time telling the difference.

Are there any inherent advantages to using either at this compression level? Again, it is hard for me to tell the difference on the TV.

[Soopafresh]

The quality of your source file is the most important factor in this case.

[trhouse]

There could be a number of reasons why this would be true independent of what you are doing. For example, if the source is VHS, VHS resolution is typically 240 lines, NTSC broadcast is 330 lines, or your TV has limiited resolution.

You might want to examine this thread for more information regarding horizontal resolution.

http://members.aol.com/ajaynejr/vidres.htm

[edDV]

352x480 is close to the original NTSC effective resolution. Analog TV horizontal resolution is spec'd in "lines of perceived resolution" as read from a test card. A rule of thumb says equivalent pixel resolution is approximately 120% of "lines of perceived resolution".

VHS ~ 240 lines (~290 pixels)
NTSC broadcast ~ 330 lines (~400 pixels)
S-VHS and Hi8 ~ 400 lines (~480 pixels)
DV video ~ 560 lines (~704 pixels)

Using this, 352x480 falls between VHS and the best NTSC broadcast in quality.

For 150 minutes per side, 352x480 is your only choice at that data rate. If the material was shot on a quality 3CCD DV camcorder, you will be tossing about half the horizontal resolution.

Added:
Capture resolution is a different subject from DVD MPeg2 encoding resolution. In most cases, capture should be done at the "native resolution" of your capture card (i.e. without scaling during capture). Most capture cards have either 640x480/576 or 704-720x480/576 native resolutions. 352x480 capture would be better off a 704 card (scaling 50%) vs a 640 card (scaling 55%, an odd value)

[slacker]

Yep, I used the Canon Optura 500 DV camcorder to shoot all of the footage.

I'm trying to save a buck while doing a good deed. I have ten football games at approx 30 minutes each. Of course, I can go to dual layer, 2 dvds, 3 dvds, 4 dvds, etc. But this is going out to 50 sets of parents as a freebie from me. I want it to look good, but I also need to be cost-conscious in putting this together.

Sounds like 352x480 is the way to go! (Although, as I commented earlier, the 704x480 at the same bitrate looks almost indistinguishable, and re-encodes in 1/4 the time that 352x480 takes using Vegas.

[redwudz]

I would add DL is expensive and not as compatible with settop players as single layer.

[edDV]

Really? What are your encoder settings?

My attempts at 704x480 at ~3 Mbps ave look worse than 352x480 at the same bitrate. But I was using TV captures.

I should try it again with good quality DV input.

[slacker]

redwuz,

I've thought about the compatibility issue and frown from using DL in this case. I would rather NOT.

edDV,

For a moment let us not be purists, but pragmatists with deadlines.

My source is already 704x480. I took DV source and fed it into my Panny dvd recorder to make 704x480 xp mode 9550 kbps vbr video 256 kbps ac-3 audio rapid, unedited copies for the football coach, for team "film" time if you will. I did not save the DV originals. I SHOULD HAVE, but they don't exist anymore. Stupid of me!

When I place the mpeg footage on the Vegas timeline and render using the DV NTSC template and only change the resolution to either 704x480 0r 352x480, and select 2-pass vbr 5mb hi, 3.7mb avg, 2mb lo, my results are EXTREMELY similar. I really can't tell the difference from 8 feet away from a 32" monitor. Sometimes I think the 352x480 looks better, and other times the 704x480 seems to look better.

They both display artifacting during heavy motion. They are not perfect, but rather borderline acceptable.

[edDV]

OK. Someday I'll compare DV to 704 and DV to 352 at those rates and play with it.