Video
Video Surveillance/Security Applications
8-Channel Audio/Video Decoder for Video
Surveillance Systems
CX25838
Conexant’s portfolio includes a comprehensive suite of semiconductor
solutions for communications and consumer applications.
High Quality Audio and Video Decoders for Surveillance Applications
The CX25838 eight-channel audio/video decoder was designed for surveillance
applications. The CX25838 contains eight high quality NTSC/PAL video
decoders with 10-bit A/Ds and 5-line comb filtering, to generate the highest
quality digital video output with the lowest possible noise. This creates
not only the best image quality for viewing, but enables lower bitrates for
compression devices using the output of the CX25838.
The video decoders within the CX25838 are optimized to lock to inputs with
low signal levels as well as line-locked cameras, both of which are common
in surveillance systems. Each video decoder may be scaled independently and
the CX25838 supports BT.656 as well as a variety of other interleaved digital
video output formats.
The CX25838 also contains eight high-quality mono audio A/Ds with I2S
outputs.
Direct-Connection to Multi-Channel H.264 CODECs
The CX25838 supports byte, line, or frame-interleaved digital video outputs at
27, 54, or 108 MHz. Byte and line interleaved outputs are supported entirely
within the CX25838. Frame-interleaved outputs require that the CX25838
interface with external DDR2 memory. The CX25838 supports I2S and
multiplexed I2S audio outputs.
Additional Features
There are two variants of the CX25838 offered — one with the external DDR2
interface, and one without the interface. When equipped with DDR2, the
CX25838 supports frame-interleaved video outputs, as well as a 2x2 CIF tiling
mode, in which four CIF images are tiled into a single D1 stream.
For systems that require resolutions of half-D1 or lower, two CX25838 devices
may be cascaded together to share external memory and CODEC interfaces.
The CX25838 includes programmable motion detection logic, which can trigger
flags over GPIO pins when motion is detected on incoming analog video
streams.
The CX25838 contains 48 GPIO pins, which maximize flexibility and allow
customization to a variety of applications and designs. The I2C interface and
motion detection flags are supported via GPIOs.
Distinguishing Features
• Eight High-Quality NTSC/PAL video decoders:
- Anti-alias filters
- 10-bit A/Ds
- 5-line comb filtering
- Independent scaling
• Eight Mono audio A/Ds
- Variable sample rates
- I
2
S outputs
• Flexible digital video output formats at 27, 54,
and 108 MHz
- Byte-interleaved
- Line-interleaved
- Frame-interleaved (requires external DDR2
memory)
• Tiling and cascading functions (requires
external DDR2 memory)
• Programmable Motion Detection
• 48 GPIO pins
Part Number
CX25838
Description
8-Channel Audio/Video Decoder for
Surveillance Systems
CONEXANT [ CONEXANT SYSTEMS, INC ]
