- Film Roll:
-
One continuous reel or spool of
film; 100 to 1200
-
-
- Sequence:
-
One contiguous set of images. There
may be multiple sequences on a roll or a storage media
unit, or a single long sequence may be split across
multiple rolls or storage media units.
CDROM:
Storage media with a maximum capacity of
700MB
DVD:
Storage media with a maximum capacity of
4.7GB, relates to 2-hours of MPEG2
video.
AVI:
A Microsoft file format. It can store
imagery uncompressed, or using various "codecs". Imagery
can also be stored compressed. This file format is
poorly documented. Most file access functions
rely on Microsoft library routines to read/write
files. Codecs are often proprietary & undocumented.
MPEG2:
An industry standard format for streaming
video and inherently uses lossy compression.
Certain Key frames are compressed using lossy compression similar to JPEG.
Other
frames are compressed, as the difference between the key frame and the current frame.
There
is usually no file header indicating the number of frames in the sequence. MPEG2
does not normally support random access to a specific frame in the file and is
not suitable for data analysis applications. This is due to its extremely
slow random access speed.
Raw Binary:
Imagery is stored pixel-by-pixel, row-by-row, frame-by-frame. No compression
means large file binary: sizes, but no
loss of data. Its an easy format to document and read.
SVS Format:
A new
format, combining both images and user defined header or meta data on
each image
frame. SVS files are integral and cannot be
accidentally separated.
SVS also stores 10-bit monochrome imagery, resulting sub-pixel resolution for
accurate data anaylsis applications.
Maximum Random Access File Size:
2.14GB. While files larger than 2GB can be read sequentially, the C
language random file access function cannot access files larger than
2.14GB
We recommend storing imagery in a raw binary format, with no
more than one sequence per file. We further recommend limiting file sizes to
less than 2GB and splitting sequences into multiple files if necessary to
achieve this goal.
- Full color resolution, uncompressed imagery corresponds to 580
image frames in one file as a 2GB file limit. That is: 1280 x 960 color (3 bytes per
pixel). Full monochrome resolution, uncompressed gray scale imagery allows 560
frames in one 2GB file. This file limit corresponds to 1534 x 1024,
2 bytes per pixel or 16-bits. However, only 10-bits are accessed. More
image frames can be stored with lower resolution and /or if lossy compression can be
used.
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