[maceye]

I have a G4/450 with 768MB of RAM, and I can't play QuickTime movies exported from Lightwave without dropping frames. Actaully dropping frames is not really the right term - it skips most of the movie, the system becomes unresponsive, and sometimes when you press play, the movies does nothing and then ends.

I tried giving QuickTime (v4.x Pro) player 450MB and then 500MB of memory, but to no avail. The movies are:

720 x 486 (D1 NTSC)
30fps
No compressor
40MB/s
Between 2 and 4 seconds long

Can anyone help me?

[scottiB]

I believe you'll need to lower the file size by compression, fps, resolution or whatever. I've run into the same occurance when QuickTiming some 30 second AutoStudio animations.

I needed to compress them down to about 6.7MB/sec (200MB/30 secs).

I have a similar rig: G4 450/512/18GB SCSI drives.

[maceye]

I guess I need to get a dual 800 then...

This is kind of wierd becuase I have an app that tells me my moving memory bandwidth - and it says about 140MB/s.

At least I know that it is a design flaw in the old G4, and not a problem with my software.

I wonder if OS X has the same problem? I think I will check now.

[scottiB]

I'm not sure if it's a memory bandwidth issue. I believe, and others can correct me--I'm a novice at this, it's more shoving the individual frames size throughput wise. I don't believe that QT loads the whole .mov into RAM.

Try creating a 100MB or so RAM disk. Copy the .mov into it and see what happens. I've never tried it, myself, but I just thought about it.

[havannas]

Originally posted by maceye:
<STRONG>I guess I need to get a dual 800 then...
</STRONG>

Heh... Not sure that would help

720 x 486 = 349,920 pixels
349,920 x 24bit color = 8,398,080 bits per frame
8,398,080/8 = 1,049,760 Bytes per frame = @ 1MB perframe
1MB x 30 fps = @ 30MB/s
4sec x 30MB/s = 120 MB read in 4 seconds

Do me a favor and copy your finished movie from one harddrive to another. I just copied a 120MB quicktime from one drive to another and it took @9 second in OsX. Thats with no other intensive processes running. Unless you're running some 80MB/s scsi drives I think your hardrive probably can't keep up. Even if it could thats a tremendous amount of data to shovel through the cpu and video-card.

from the dvdfaq:
"At average video data rates of 3.5 to 5 Mbps (million bits/second), compression artifacts may be occasionally noticeable. Higher data rates can result in higher quality, with almost no perceptible difference from the master at rates above 6 Mbps."

Thats for a dvd with a dedicated circuitry for decoding. They use for peak action scenes probably 8 Mbps or @ 1MB/s. Your using 30MB/s. Unless your done with your project and are about to print-to-video. I'd seriously consider using compression. Incidently that 120MB file I used in my example was at 1024x576 pixels, 15 fps, SorensonVideo. It is 3 minutes and 42 seconds long and has a data rate of @ 550 KB/s. Also has an uncompressed Stereo 32kHz /16 bit audio track. It's not perfect quality but is was good enough to be used on a 42" Fujitsu 16x9 Plasma display at a tradeshow.

Just curious how will this eventually be published? Web? Cd-r/DVD? Out through a DV or analog converter? I generally use Animation compression at high quality/30fps for my initial output. Animation at it's high quality setting is basically lossless, just run-length compressing the video (unless your using key-frames). Just using that might be enough to get your video down to 5-8 MB/s and Animation compresses fast. Then when your sure your project is done you can really crunch it down with Sorenson. Anyway hope this helps.

Heh... not to a hypocrit but.... my dual 800 just shipped, should be here next week. Gonna be quite a leg up from this 400Mhz Yikes G4.

[maceye]

Well, I made a RAM disk, and the movie played smoothly. I noticed that it took about 10 seconds for the file to be copied into the RAM disk. I think that explains the problem with the movie - the HD was WAY too slow.

Well, now that I have seen my 160MB movie, I'm not sure if it was worth all the time. Although it looks really good.

Thanks for the help