Assuming I'd rather use H.264 than MPEG Visual for unspoken
reasons, is there any reason anyone can think of other than the
loss of QT6 compatibility that this might be a bad idea?
I haven't really done any serious size or quality comparisons yet and
don't have a video-capable iPod to test with, but you might consider
going with 480x270 size MPEG-4 video for 16x9 material. The first
test clip I've done is here...
These were done at roughly the same bitrate, but MPEG-4 video for the
iPod supports up to Up to 2.5 Mbps while H.264 only supports up to
768Kbps. Here are the full specs from Apple's site...
H.264 Video: Up to 768 Kbps, 320 x 240 pixels, 30 frames per second,
Baseline Profile up to Level 1.3
MPEG-4 Video: Up to 2.5 Mbps, 480 x 480 pixels, 30 frames per second,
Simple Profile
The real question that I haven't yet had time to answer is whether
the quality of an MPEG-4 clip at 480x270 is better on a computer than
a 320x180 H.264 clip scaled up to that size and in particular which
clip is better when using Quicktime Player to present the movie full
screen? IOW, does the higher resolution make it a better solution for
both computer playback and iPod playback? I doubt you'd be able to
tell any difference when viewing on an iPod and I'm not sure about
the PSP.
To my aged eyes, the MPEG-4 clip is a little crisper at its native
size than the H.264 clip scaled up to that size. Both are a little
fuzzy, but acceptable when using Quicktime Player to present full
screen at 1368x768.
Regarding delivering 16x9 vs. 4x3 letterboxed video, if you deliver
16x9 then it should play back correctly on both 16x9 and 4x3 devices;
if you deliver 4x3 letterbox, then 16x9 devices will likely play back
the clip window boxed with black bars on all four sides.
Dennis
--
Dennis Whiteman
email@hidden
"I'd rather be in Iraq."
-- Sgt. Jason Defess, National Guard, in New Orleans
