|.txt -- text only,
no formatting, no graphics or other media
|Created in or Saved as
Word, Notepad, Wordpad
|.rtf -- formatted text, usable
on any platform (PC, Mac, UNIX)
|.doc -- formatted text
may include graphics, tables, other media
|.wps -- ditto
|.pdf -- format and layout, text
with or without graphics
for viewing and printing
|Created in Netscape, or copied
and pasted into Netscape
from text typed in Word
|Created in Word and saved as
||640 x 480 pixels
||see Control Panel, Display, tab
Settings on your computer
-- the user may see your image in a different size
|full screen: Calculate
for different displays
||800 x 600 pixels
||abt. 2/3 of the screen
||1024 x 768 picels
||abt. 3/8 of the screen
400 x 561
|JPEG/JPG||144 KB||1 %|
|JPEG/JPG||16 KB||70 %|
A good rule of thumb: Each minute of 16-bit stereo sound
at 44.1 kHz requires about 10 Mbytes of disk space.
Thus, with an empty 200 Mbyte hard disk you can record a little less than 20 minutes of CD-quality stereo sound (eprecisely, 19 minutes, 20 seconds).
Example: I recorded 13 seconds of sound
the ITC corridor, 16 bit stereo 44,100 hz: This is a 2.5 M file, format
.wav -- and it should to be compressed. (For speech, you need
only 8 bit mono
its file size would still be big and its sound quality would be so-so..)
Audio files compressed to other formats,
such as rm or MP3,
might be smaller, take less disk space and transmit faster.
|sonic.rm (same as above)
|greater bit depth
||sonic1ac.mp3 (same as above)
|../audio/heartsounds.html||00b10001.wav||62 KB||3 sec|
Reducing the frame rate to 10 frames per second may produce choppy
the data rate at 2.3 MByte/sec.
(This data rate is too high for old hard drives, old CD-ROM (2x drive ~ 200 Kbyte/sec sustained ) or modems (28.8 modem ~2.88 Kbyte/sec; 56.6 modem~5.66 Kbyte/sec).
Greater compression will knock this down further, but higher
make compressed video look better. Compromise!