Compression, compression !

ChristerTX wrote on 7/26/2004, 7:50 PM
I have this challenge:

I'm creating a video that is being FTP's to Australia.

I need to keep the file size small but still 720x620 resolution.

When encoding, should I play with frame rate or what? What will give me the most reduction in file size but still a qood quality?
MPEG2 will give me a 1.3 gb file and that is too big.
DivX encoding will yield a 500Mb file and that is ok but the quality is not so good. (low light subject and movement is a challenge)

Comments

laz1 wrote on 7/27/2004, 6:34 AM
I'm surprised DivX isn't good quality, but if you render to mpeg1 this should be ok.
Chienworks wrote on 7/27/2004, 8:31 AM
How long is the clip? What's the frame rate? What sort of action does it have in it?

Remember that for the most part, high quality and small filesize are incompatable.
ChristerTX wrote on 7/28/2004, 1:52 PM
This clip is about 30 minutes.
It is a speaker on a stage who is pacing back and forth and sometime stand still. There is some zooming in on the speaker.

The settings are these:
720x480x32
Frame rate: 29,970fps
Average bitrate: 780 kbps

I'm right now trying to up the bitrate a bit to see what happens.
Chienworks wrote on 7/28/2004, 7:52 PM
780Kbps should result in approximately 174MB (some guesswork involved). 3Mbps will probably result in a respectable quality at about 680MB or so. Your 1.3GB file must have been encoded at about 6Mbps. You can go as low as 1Mbps for MPEG2 if you wish, but at reduced quality. If you end up encoding at less than 1000Kbps then i would recommend a half-size frame at 320x240. You may actually get a clearer picture at that size than a full frame.
ChristerTX wrote on 7/29/2004, 5:12 AM
I tried the Xvid MPEG4 codec with great results.
That gave me a file size of 933Mb file compared to the 1,3gB file for MPEG2.
The MPEG2 was made with the standard settings.

The DivX codec gave me a smaller file (512mB) but the image was too blocky.

Thanks / Christer
ChristerTX wrote on 7/29/2004, 5:14 AM
How can I change the MainConcepts codec to do 3Mbps?
Chienworks wrote on 7/29/2004, 8:48 AM
Click the Custom button and switch to the Video tab. You can type in just about any bitrate you want. The lower limit is 192,000. Anything above 9,800,000 probably won't play well in most devices.