I wrote this up on another forum today, and felt the need to share it here, too...
I've seen this discussed in other threads lately, so I've created this new thread on this topic here in the tech area.
Now, I know many of you like to use SP mode, but I have to rain on your parade. It's not all that superior, not necessarily. Recordings are being discussed not by specs, but by fake "modes". The times are all being discussed by episodes, instead of by minutes. Remember that many episodes of shows these days (especially Saturday morning cartoons) don't even come close to 23-24 minutes. Most of my THE BATMAN episodes were only 19 minutes long, and I easily fit 10-11 episodes on a single disc. It can be done.
I've gone over this before, but I guess I need to do it again. SP mode on a DVD recorder is 720x480 Full D1 at 5000-5500k VBR. Now those bitrate specs give a fairly high compression rate, and that can range from okay to minimally acceptable.
On the other hand, 352x480 requires about half as much bitrate to look good. For example, a 720x480 5000-5500k encode is visually the same as a 352x480 2500-2750k encode. The resolution might be less, but if your source is not 720, then you can't really notice anyway. For many folks that insist there is, it's really just all in their head (or due to inferior hardware). Not coincidentally, the CVD/SVCD specs are 2520k VBR fixed.
This is nothing more than simple math. For 11 episodes, at 20 minutes, you're looking at 220 minutes of video. With 256k audio bitrate (standard AC3 or MP2), you're looking at 2450k -- that equates to 4900k (5155k, audio inclusive). That's the same compression as an SP mode disc!!!
You need to remember that cable, antenna and satellite, for standard definition sources, are still in the meager (digital equiv) 400-500x352 average resolution. Half D1 352x480 is not that far away, and "softness" that people complain about is often a direct result of their hardware or software, not the resolution itself. For example, Hauppauge PVR cards and older Panasonic DVD recorders are soft at 352, whereas cards like ATI All In Wonders are tack sharp. Panasonic also has the infamy of making blocky encodes at Half D1. You're not necessarily getting anything extra from making it a 720x480 encode over a 352x480 encode.
Higher-compressed video yields compression noise quite often, what many refer to as "mosquito noise". It's not blocks, but that noise you get before it's so bad that it forms blocks.
More bitrate is one way to get a better image (within reason), refer to some of the bitrate charts on this site
for more details on this. So instead of a meager 352x480 2500k, something along the lines of 3000k or even 3500k will look better. In fact, 3500k is starting to reach maximum threshold, before you hit a point of diminishing returns.
This is why a 3-hour or 3.5-hour disc if often cleaner/better looking than a 2-hour SP mode DVD, assuming it is 352x480 and made with good hardware/software. It has a higher allocation of bitrate, or bits per pixel.
Much of my work is done in higher-end hardware or MPEG encoding software, where I pick the exact specs that I want for my projects. If I ran a 2-pass VBR encode in higher-end software like MainConcept
Reference or Procoder, noise would be minimal, even at a maximum compression of 2000-2500k VBR at 352x480. Hardware, on the other hand, is not quite as good at compression quality, at least in the hardware any of us is likely to use.
So before you criticize the length of material on a DVD, consider these factors. Ask how a DVD was made, what hardware and software was used, what the bitrates are. It's not all that unlikely that a well-made 11-episode DVD will look better than the 5-episode DVD your created on a cheap DVD recorder!!!
I'd much rather have a well-made 3-4 hour disc, than a budget-grade "SP mode" 2-hour DVD.
You have seen my work, and I've seen some of yours. Don't make me pull samples and compare.
The only thing SP mode really has going for it, is that it is a "safe" mode to use. Machines are attuned to it, and more often than not, you can get a decent product from it. All other modes vary wildly from unit to unit, even XP mode has problems on some machines (bitrate spikes), while slow modes can add blocks or look awful. SP mode is the devil you know. On some machines, SP mode is the ONLY mode worth using. Yikes!
Food for thought, ladies and gents.