Pike Technical Manual
V5.2.0
249
Video formats, modes and bandwidth
Frame rates
An IEEE 1394 camera requires bandwidth to transport images.
The IEEE 1394b bus has very large bandwidth of at least 62.5 MByte/s for trans-
ferring (isochronously) image data. Per cycle up to 8192 bytes (or around 2000
quadlets = 4 bytes@ 800 Mbit/s) can thus be transmitted.
Depending on the video format settings and the configured frame rate, the cam-
era requires a certain percentage of maximum available bandwidth. Clearly the
bigger the image and the higher the frame rate, the more data is to be transmit-
ted.
The following tables indicate the volume of data in various formats and modes to
be sent within one cycle (125 μs) at 800 Mbit/s of bandwidth.
The tables are divided into three formats:
They enable you to calculate the required bandwidth and to ascertain the num-
ber of cameras that can be operated independently on a bus and in which mode.
Note
Configuration
To configure this feature in an advanced register see Chapter
Note
All bandwidth data is calculated with:
1 MByte = 1024 kByte
Format
Resolution
max. Video Format
Format_0
up to VGA
640 x 480
Format_1
up to XGA
1024 x 768
Format_2
up to UXGA
1600 x 1200
Table 99: Overview fixed formats
