Preparser
6-25
The payloads of transport packets that contain PES data are presented
over the parallel channel interface. The AVALIDn or VVALIDn strobe
indicates the type of the elementary stream. For Audio PES streams, the
Preparser stores the PES header in the Audio PES Header Channel
Buffer, INTRn is asserted if not masked, and the Audio PES Data Ready
Interrupt bit in Register 2 (
page 4-6
) is set. The Preparser stores the
audio stream in the Audio ES Channel Buffer. For Video PES streams,
the Preparser stores the video PES header in the Video PES Header
Channel Buffer, INTRn is asserted if not masked, and the Video PES
Data Ready Interrupt bit in Register 2 is set. The Preparser stores the
video stream in the Video ES Channel Buffer. The Preparser then adds
the buffer write pointers for the start of the audio and video streams after
the headers in the PES header buffers. The purpose of the write pointer
is to allow the host software to connect the PES header with the next
access unit such as a video frame.
The start address, end address, read pointer, and write pointer registers
for the Audio ES, Video ES, and Audio PES Header Channel Buffers are
those listed for Elementary and MPEG-1 streams in
Table 6.8
and
Table 6.9
.
Note:
The registers for the Audio PES Header Channel Buffer are
the same as those used for the System Channel Buffer in
MPEG stream modes.
The registers associated with the Video PES Header Channel Buffer are
shown in
Table 6.12
.
6.3.8 Error Handling in A/V PES Mode
The paragraphs in this section list the error check points, and describe
the errors at the check points and their handling for MPEG-1 and
MPEG-2 audio and video.
Table 6.12
Video PES Header Channel Buffer Registers
Address
Registers
Page Ref.
Video PES Header Channel Buffer Start Address
80 and 81
4-24
Video PES Header Channel Buffer End Address
82 and 83
4-24
Video PES Header Channel Buffer Write Address
102–104
4-27