1: Introduction microH264-D4 Hardware Reference Manual
© 2011 Advanced Micro Peripherals
Document version A.02
Real time live video H.264 encoding
Digital video data streams from the 4 Frame Stores are routed to the hardware
H.264 encoder engine where the video can be compressed.
Each of the video channels can be compressed to a separate H.264 stream,
resulting in four separate H.264 streams which can be written to disk (or LAN) as
separate files. These streams can be up to full size at full frame rate.
The encoding engine continuously encodes the video streams and uses its PCI
bus Master/Initiator interface to transfer data across the bus to the system
memory or disk.
Note: The encoding path only supports a simple text overlay capability.
Video Preview
The microH264-D4 provides a secondary video path allowing the recorded video
to be streamed to the graphics controller buffer of the host system for video
previewing. The Preview output can also be used to view an alternate video
source while recording other inputs. The Preview information is also available as a
composite NTSC/PAL output suitable for driving a NTSC/PAL or RS-170 display
device.
Note: The VGA preview output does not include an overlay capability, however,
the composite analog output does offer support for full color, bit mapped graphics
overlay with alpha-blending.
Real time H.264 video decoding / playback
The microH264-D4 can receive H.264 encoded video data over the PC/104
-Plus
bus and decode it to a raw digital video stream. This is fed into a high speed
digital-to-analog converter and then encoded to analog composite video as either
NTSC or PAL. Additionally, the raw digital video stream can be displayed on the
system VGA using the real time video preview functionality.
Maximum image size of decoded video is 704x480 (NTSC) or 704x576 for PAL.
Audio data which is part of the original recording is also decoded and played back
in synchronization with the video.
In addition to playback to the system display VGA device, the microH264-D4 also
provides a composite NTSC/PAL playback output suitable for directly driving a
PAL/NTSC or RS170 display device.
OSD Video Text/Graphics Overlay
The microH264-D4 has two supported modes for OSD overlay;
A simple (single color) text overlay may be added to the recording path for the
video data. In addition to this, a full color bit-mapped graphics overlay feature is
available for the analog preview output. This offers a choice of 64k colors (16 bit)
