L64105 LSI Logic Corporation, L64105 Datasheet - Page 171

• Manufacturer Part Number: L64105
• Description: Mpeg-2 Audio/video Decoder
• Manufacturer: LSI Logic Corporation

Figure 4.131 Register 367 (0x16F) Host Category [7:0]
7
Overwrite Quantization Enable
MPEG Formatter Only
Formatter Skip Frame Size [1:0]
Reserved
This value can be set by the host to override the existing category code
when the Overwrite Category bit (bit 0 in Register 366) is set.
Audio Decoder Registers
When the host sets this bit, the value of the quantization
parameter is specified by the Host Overwrite
Quantization bits (bits 1 and 2 in this register]). When this
bit is cleared (default), the quantization is as specified in
the bitstream.
When this bit is set, the MPEG Formatter runs stand-
alone without the MPEG Decoder being activated.
These bits control the behavior of the MPEG Formatter.
To achieve synchronization between the MPEG Audio
Decoder and the output sent to the IEC958 (S/P DIF)
Interface, the formatter may decide to skip entire frames
or to pause (wait) for a frame. The decision to skip or to
wait is made by the formatter after comparing the fullness
level of the internal buffers (FIFOs) that feed the input
MPEG bitstream to the decoder and formatter. When the
difference in fullness levels of the two buffers goes
beyond a certain threshold, the audio output of the DAC
and S/P DIF will not be considered as acceptably
synchronized. When this happens, the formatters take
appropriate action, either skipping a frame or waiting until
the two get back in synchronization. The only setting for
these thresholds is 0b00, 2 frames.
Set this bit when writing to this register.
Host Category [7:0]
R/W
R/W [6:5]
R/W 3
R/W 4
0
4-89
7