640x480 @ 30fps from digital still cameras

[newbie]

Hello all,
I'm starting to use digital still camera as video camera. Since the quality of these videos produced from these cameras are acceptable. (I'm using Canon A620 and it uses motion JPEG).

What your recommendation for converting these videos to? That is, what resolution should they be converted to?

1) 720x480 @ 29.97 fps (D1) OR
2) 352x480 @ 29.97 fps (D2) OR
3) 480x480 @ 29.97 fps (SVCD) ?

Sorry if this has been asked before.

[junkmalle]

720x480 @ 29.97 fps (D1) unless you're looking to put a lot of video on a DVD. SVCD wouldn't be losing too much resolution but the bitrate is too low for shakey handheld camera footage and high action scenes.

[Des]

I do this quite often with my Minolta Z2. I use 680x480 at 30fps and convert to 352x480 for presentation. I usually mix the videos in with a slide show using Proshow gold.
The results are not stellar but usually very accpetable unless I push the digital zoom too much (I have the optical zoom turned off for video as it is too noisy).
Most of my clips are under a minute so it certainly seems to pass the audience test even when using the video projector.

--dES

[newbie]

720x480 @ 29.97 fps (D1) unless you're looking to put a lot of video on a DVD. SVCD wouldn't be losing too much resolution but the bitrate is too low for shakey handheld camera footage and high action scenes.

Enlarge the resolution? Aren't we loosing the quality due to enlargement? I've been thinking of converting them to 352x480 @ 29.97 fps to make sure I won't introduce artifacts due to enlargement.

So what encoder is best for enlargement?

[lordsmurf]

These stills will look okay on tv, but like hell on printed paper, or even the computer screen.

[junkmalle]

720x480 @ 29.97 fps (D1) unless you're looking to put a lot of video on a DVD. SVCD wouldn't be losing too much resolution but the bitrate is too low for shakey handheld camera footage and high action scenes.

Enlarge the resolution? Aren't we loosing the quality due to enlargement? I've been thinking of converting them to 352x480 @ 29.97 fps to make sure I won't introduce artifacts due to enlargement.

So what encoder is best for enlargement?

Think of it like this: both 720x480 and 352x480 will be displayed the same size on your TV. If you shrink to 352x480 you are throwing away nearly half the resoltion to start with. Then the DVD player is enlarging that to the equivalent of 720x480 for display on the TV. You are losing far more doing that than enlarging the 640x480 to 720x480.

But don't take my word for it -- do the tests yourself with a few short clips on a RW disc. Try a scene with some text that is barely readable at 640x480. The 720x480 version will still be readable. The 352x480 will not. Unless your video is blurry to start with.

Of course, if you plan to cram 4 hours on a DVD you may be better off with 352x480 because the low bitrate required will do better at that resolution. You'll be trading resolution for fewer macroblocks.

The best enlarging filters would be AVISynth's Lanczos4 or VirtualDub's Lanczos3. A bicubuc enlargment may be a little sharper but will introduce moire artifacts on some shots. Even TMPGEnc's enlarging filter (appears to be bilinear) will be OK for enlarging 640 to 720.

[newbie]

Thank you junkmalle,
That's very clear. It totally makes sense to me now. I'll do that.

[junkmalle]

Here are some samples:

640x480 source:


Resized direclty to 720x480


Resized to 352x480, then to 720x480 (as your DVD player might):


The last image is a simulation of course. We can't know exactly how the DVD player will enlarge the image. But no matter how it does it, it will have less resolution to start with and it won't be able to restore what was lost. I used Lanczos3 in VirtualDub for all the resizing here.