[MacDV] Re: Did it. (Encoding iDVDs at a lower bitrate)

[Jim Heid]

>> Whatever the bottom line, I'll bet the quality would be atrocious.
>> 
>> iDVD's lower bitrate -- the one you get when you have more than 60 minutes
>> of video -- is 5Mbps, and that's at the low end of the acceptable-quality
>> level for iDVD's MPEG encoder. Indeed, IMO, the quality is unacceptable for
>> anything but rank-amateur work.
> 
> I'd recommend you take a look at some actual samples.
> I've run through a few different bitrates now and
> the encoder does much better than I'd expected at
> the lower bitrates.
> 
> Don't forget: in many cases, it's not the final Mbps
> but the encoder that makes the visual difference.

Indeed, but Apple's encoder is optimized for speed, not quality. Its quality
sweet spot is in the 7-8 Mbps rate, and to get that with iDVD, you've got to
stay below 60 minutes of content.

And what really makes the difference is the quality of what you're encoding.
Well-shot footage (properly lit and shot with a high-quality, tripod-mounted
camera) will compress much better at low bit rates than will footage shot
with poor lighting and a cheap, hand-held camera.

> p.s. And what's wrong with amateur work? A lot of
> list members are hobbyists.

Absolutely!! But an amateur should still care about the quality of his/her
work. For example, if I was using iDVD to burn and distribute a 72-minute
movie, I'd rather have the movie span two discs and provide an intermission
break than force iDVD to downshift to 5Mbps.

If there are fellow old-timers on this list who remember reel-to-reel
audiotape recorders, here's the analogy: You could squeeze more audio on a
reel of tape by recording at 3-3/4 inches per second instead of 7.5 ips, but
the quality suffered.

When quality counts, it's better to use more tape. Or DVD-R blanks.

Best,
Jim
--

Jim Heid
Author/Host, "The Macintosh iLife" book/DVD
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