Enhanced PCI Bus Multimedia Controller
1.0 INTRODUCTION
for compression. The ZR36050 drives the code stream to the
Codec Front End of the ZR36057, which transfers the com-
pressed video fields using DMA to a system memory buffer
allocated by the host.
1.1 The ZR36057
The ZR36057 is a PCI adapter intended for multimedia applica-
tions on PCI systems. It supports high rate code (compressed
data stream) transfer between the system memory and JPEG or
MPEG processors. Simultaneously to the code transfer, the
ZR36057 captures digital video, such as decompressed MJPEG
(Motion JPEG), MPEG, or the output of a video digitizer/
decoder, and creates a scaled video window in the graphics
display memory.
1.2.2 Motion Video Decompression
In Motion Video Decompression, the ZR36057 transfers the
code stream from system memory via the ZR36057 Codec Front
End to the ZR36050, using DMA. The ZR36050 decompresses
the JPEG code and transfers the decompressed blocks to the
ZR36016. The ZR36016 performs the block-to-raster conversion
and drives the video to the video encoder to be displayed on a
TV monitor. The ZR36016 video output is driven simultaneously
to the Video Front End of the ZR36057 to be processed, as in the
capture mode, and transferred using DMA to the PC display
memory.
The ZR36057 provides the host software with full control over a
large number of non-PCI multimedia devices such as: ZR36050,
ZR36016 (Zoran Motion JPEG Codec chip set), audio codecs,
ZR36100/ZR36110 (Zoran MPEG decoders), etc, as well as any
number of I2C devices, such us video digitizers, video encoders,
etc.
The ZR36057 interfaces directly to the PCI bus. As a bus
master, it transfers data (e.g, MPEG or JPEG code) to or from
the system memory, and writes digital video pixels to the
graphics display memory. As a bus target, the ZR36057 reflects
the host accesses onto a microcontroller-type 8-bit “Guest Bus”.
1.2.3 Still Image Compression
In Still Image Compression mode an image bitmap is written by
the host, pixel by pixel, through the PCI bus to the ZR36057. The
ZR36057 transfers the pixels through its video bus port to the
video input port of the ZR36016. After the first strip of 8 video
lines is filled, the ZR36016 starts performing the raster-to-block
operation, sending the blocks to the ZR36050. The ZR36057
generates and drives the required video synchronization signals
for the ZR36016. The ZR36050 compresses the video blocks
and drives the code stream to the ZR36057. The code stream is
transferred using DMA to the host memory as in Motion Video
Compression.
The ZR36057 has a special “Still Transfer” port by means of
which the host software writes (or reads) digitized video, as RGB
pixels, from the system memory to (or from) the video bus. This
path enables fast transfer of still images to be compressed (or
decompressed) by the JPEG chip set.
1.2 JPEG System Overview
Figure 1 depicts an example of an MJPEG add-on board.
The ZR36057 supports 4 basic JPEG modes of operation:
1.2.4 Still Image Decompression
In Still Image Decompression mode, the ZR36057 fetches the
code stream from system memory using DMA, as in Motion
Video Decompression. The ZR36050 reads the compressed
data from the ZR36057, decodes it and send the expanded
blocks to the ZR36016, which drives the video to the video port
of the ZR36057. From there the host software reads it out to
system memory, pixel by pixel.
• Motion Video Compression.
• Motion Video Decompression.
• Still Image Compression.
• Still Image Decompression.
1.2.1 Motion Video Compression
Note that still image decompression can also be accomplished
by configuring the ZR36057 in Motion Video Decompression
mode, and transferring the decompressed video to a contiguous
buffer in system memory instead of the display memory. Since
this has a speed advantage over Still Image Decompression
mode, it is the preferred method for most applications.
The video decoder directs the video in YUV 4:2:2 format, and the
video synchronization signals, to the video input port of the
ZR36016. The video is also transferred to the video encoder for
display on a TV monitor and simultaneously to the Video Front
End of the ZR36057. The ZR36057 can optionally down-scale
the video, convert it to RGB, and transfer the pixels using DMA
to the display memory of the host PC. In parallel, the ZR36016
performs the raster-to-block operation needed by the JPEG
algorithm and transfers the video in block order to the ZR36050
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ZORAN [ ZORAN CORPORATION ]
