90MB for 3m45s at 240x196 is not good.

Be sure your keyframes are set to 300, that's the biggest step for most people.

For the rest (there is certainly more to fiddle with), look for earlier posts per BJ_M's suggestion.

I got a 5m12s, 500x384 resolution (yes, vertical), 30P video down from 90MB to 17MB without excessive quality reduction in QT. That took a significant amount of testing (for me) though, and it's difficult to offer simple cookbook recipes.

i thought he said 9meg , not 90 meg

doesnt sound like sorenson was used

File size is determined by the length of the video and the bitrate used for encoding. The frame size and frame rate don't matter when calculating file size. To get 90MB from 225 seconds you must have encoded at 3Mbps (3000Kbps). This is very high for web delivery. Many web videos are encoded at 256Kbps or thereabouts. At this rate, with no other changes at all, your file size would drop to around 8MB which is a good size for web delivery. You should also be able to get away with a frame size of 320x240 and still have a semi-decent looking picture.

"The frame size and frame rate don't matter when calculating file size."

Both of these do matter for a given quality, i.e. if you reduce the frame rate or the frame size you can increase the bit rate for a given file size, which increases the video quality.

No you can't. If you render 320x240 30fps at 256Kbps you will use 256K bits per second. If you render 160x120 10fps at 256Kbps, you will still use 256K bits per second. The resulting file size will still be essentially identical.

The frames of the 160x120 10fps video will be sharper and clearer than the 320x240 30fps video. This is because there are more bits available for each frame and the image won't be compressed as much.

Using a smaller frame size or lower frame rate will let you use a lower bit rate to maintain the same quality. However, to get a different file size, just changing the frame size or frame rate won't make any difference. You have to use a lower bit rate to get a smaller file size.

True, the frame size and frame rate matter a lot for quality. If you want a small file size then you'll have to use smaller frames and slower rates to get better quality images ... because you will be using a lower bitrate to get a smaller file. Just changing the frame size or rate alone won't alter the finished file size at all.

For compressed video, file size is determined only by the length of the video and the bitrate used.

Thank you for your help everyone - this is where Im at:

I have got the size down to 7MB with the following settings
REnder Quality=Good
Frame Size = 240 X 196
Frame rate = 15 Field Order = None Aspect Ratio = 1
Video Format = Sorenson Video 3
Compressed Depth = 24 bpp Quality = 50% Data Rate = Basic
Target Rate = 28
Key Frame every 300
Streaming = Fast Start with Compressed Header

Do these sound ok ? Not sure about the target rate.

Quicktime uses bytes per second for the rate instead of bits per second, so 28KBps = 224Kbps, which is a probably good for that frame size. 15 frames per second is a good choice too since that lets each frame have twice as many bits for a clearer image. You might be able to get away with a 320x240 frame, but you would just have to try it and see how it looks.

you are right chienworks - I should have said reduce the frame rate AND data rate ..

I just assumed that this was a given .....




this why 24p w/ pulldown mpeg encoding is more efficient for dvd --

Why is the 320x240 frame dimension preferred over 360x240? Aren't the black bars prohibitive? Wouldn't I rather have more of my original DV frame where they are?

Incidentally, I just did an 8:17 piece that looks nice and it's "only" 31mb:

http://ideaspora.net/breadstuy.mov

Settings are: target bitrate of 100kBps, 360x240, 15fps progressive PAR .9091 sorenson 3 | 16 bit, 22050khz mono audio, QDesign Music 2

- jim

Chienworks,

It sounds like we are talking about two different things.

Your math is impeccable, but as you yourself said, "Using a smaller frame size or lower frame rate will let you use a lower bit rate to maintain the same quality."

That's all I was talking about.

I look at it first from a viewer's standpoint, and what he or she might perceive as a reasonable compromise between subjective quality and download time, given what exactly I am trying to communicate. The upper limit on the file size is then usually determined by the web site owner (who is paying for the bandwidth bills).

Related subject:
The WM9 player is supposed to be able to do frame interpolation so you can feed it say 15fps and have it play back at a 30 fps rate with the action at normal speed. I never spent much time on this, because I couldn't get any useful improvement from it. Anybody have good experience with this?

it does a terrible job at it

should use 1:1 PAR