🚀 go-pugleaf

David Longley <David@longley.demon.co.uk> wrote:

>Five  minutes of VHS capture at half PAL produces a raw  file  of 
>about 60 MB.

>WHat is the maximum, and, in everyone's experience, best one  can 
>hope for using the Windows based software MPEG drivers? I suspect 
>that  5mins  is really CD material and only under 15  seconds  is 
>viable for floppy storage even if compressed.

>Can we have a discussion on this subject?
>-- 
>David Longley

MPEG Compression can vary depending upon the quality you want.  This
quality is comprised of the following issues:
1. Frame Rate - 30 frames per second is preferred but you will often
see reduced frame rates used to store more video in a given amount of
space.
2. Resolution - The nominal MPEG resolution is 352 x 240.  However,
many people distribute MPEG on the net at lessor resolution, often 160
x 120.  Again, a big space saver.
3. Compression Ratio - The more you compress, the smaller the file.  A
good encoder can compress from a full BTSC/CCIR601 video stream
representing over 30 MB/S to around 150K per/second and still maintain
very good quality.  However quality is subjective.
4. Audio - MPEG1 can use CD quality 16 bit audio or lower quality 11
KHz, mono audio.  Mono uses less space.

So, to figure out what will fit where, just do some math.

At 150K per second (pretty high quality video at MPEG1) you get 72
minutes on a CD ROM and around 9 seconds on a floppy.

Change the above facters to fewer frame rates, lower resolution and
mono audio and get a LOT more.  In reality, your application will
determine your quality requirements.

Good Luck

Ray Harris
President
Optibase. Inc.
MPEG Video Compression and VOD
5000 Quorum Dr., Suite 700, Dallas, Tx. 75240
US 800-451-5101, Int. 214-774-3800, Fax 214-239-1273
EMAIL rayh@optibase.com, direct phone 214-774-3870