Bob Currier (rcurrier@synthetic-ap.com)
Fri, 11 Jun 1999 02:18:09 -0700
On 10 Jun 1999 09:25:30, MoovyMagic@aol.com wrote:
>Not necessarily stuck to RealVideo. There are several codecs available, and
>so far none have created an AVI in PC-world that will play acceptably when
>taken to a Mac.
<snip>
>What problem I see with QT3 locally on my PC is ---none. I can make a short
>video, with any of the codecs on the system via the edit-render provision in
>the edit program, and I can play it back just fine. When I then take this
>video on a Jaz disk to a friend's --who is Mac based-- we first copy it over
>to his high-speed A/V drives, and he can't play it with QT3 or anything
>else.
> We have supposedly stuck to codecs on the PC that he also has on the
>Mac--even to the same rev number.
I'm still not clear on whether the AVI on the Mac just plays
"unacceptably" (i.e., dropped frames, etc.) or won't play at all (i.e.,
it won't even open).
If it just won't open, rather than double clicking the AVI file, try
starting MoviePlayer and using File>Open to open the file. In the event
of a non-Mac-compatible codec, you should at least get an error message.
QuickTime 4.0, with QuickTime Media Exchange enabled (in the QT control
panel) does a much better job of recognizing AVI files so you can just
double click. QT 3 wants you to set the type and creator correctly or to
open from within MoviePlayer.
If it sorta plays but not acceptably, then I'd just say that asking for
full frame, field-rendered, 30fps video may be asking too much of your
friend's Mac, even with AV drives. You're doing better than I can if you
can get AVIs of that sort to play smoothly on your PC. My 400MHz PII
won't, unless I'm using a codec that is supported directly by my capture
card (MPEG or proprietary M-JPEG) and that's kind of cheating since the
card is doing all the work.
You're right that most people claiming "full screen, full motion" video
are using a doubled 320x240 Sorenson-compressed image. It can look good,
but it *is* cheating. The fast G3s can support 640x480 Sorenson at 30fps,
providing you compress it very carefully (VBR and a *low* datarate).
I think the reality is that AVI is not a performance solution on the Mac.
There are many reasons for this: I suspect that it is generally seen as a
"compatibility tool" and doesn't receive as much performance tuning; many
of the AVI-specific codecs are designed with Intel byte-ordering
(requiring every byte to be swapped on the Mac, rather than just copied
to the display); the newer Intel Indeo codecs are specifically designed
to use the MMX instruction set and perform badly even on PCs without MMX;
I don't think any of the AVI-specific codecs take advantage of the video
card acceleration found in the G3 machines; and AVI support on the Mac is
integrated into QuickTime, which is very elegant, but is not a real good
fit, leading to some performance hits (audio interleave differences come
to mind).
The (current) Mac hardware and software is certainly capable of the
performance you're looking for (Commotion Player gives me uncompressed D1
frames at 90fps, albeit after being loaded into memory) but I don't think
AVI is the right choice for the Mac for "real" video playback.
This archive was generated by hypermail 2.0b3 on Fri Jun 11 1999 - 02:22:42 PDT