Filter
Top Products
2004 Jan 26 19
Philips Semiconductors Product specification
MPEG-2 video and MPEG-audio/AC-3
audio encoder with multiplexer
SAA6752HS
7.3.2 VIDEO ENCODER CONFIGURATION OPTIONS
The following configuration options can be selected from
the host:
• VIDEO COMPRESSION SETTINGS. I, IP and IPB
encoding with various GOP structures can be selected.
• ENCODER BIT RATE. The bit rate for variable bit rate
or constant bit rate modes can be programmed using bit
rate and quantization control parameters. These
parameters can be adjusted whilst encoding, not just set
at initialization.
• ENCODER PERFORMANCE TUNING. The ability for
the user to tune encoding performance is provided by
allowing control of adaptive quantization depth. Also the
SAA6752HS allows download of new quantizer matrix
contents.
7.3.3 VIDEO ENCODER STATUS INFORMATION
The following status information is available to the host:
• CURRENT ENCODER BIT RATE. The actual encoded
bit rate, as number of bytes per GOP, is available
allowing the use of constrained variable bit rate
algorithms to fine tune the encoding efficiency.
7.3.4 GOP STRUCTURE
The programmable GOP structure features a reference
frame distance (M) up to 3, and a GOP length (N) of up
to 19. Supported structures are real closed GOP(M,N) and
backward predicted closed GOP(M,N). For the use of
B-frames in D1 and 2/3D1 mode a 64 Mbit SDRAM is
needed.
In D1 mode, B-frames will be unidirectional. Backward
predicted closed GOPs may have the first one (M = 2) or
two (M = 3) B-frames referenced inside the GOP
dependent on the I
2
C-bus register settings. This is
intended for editable applications as GOPs are
independent of each other. Non-editable GOPs allow the
first one (M = 1) or two (M = 2) B-frames to be referenced
to the P-frame in the previous GOP. This is a non-editable
format but has optimum encoding efficiency. This structure
is sometimes called an open GOP. The first one (M = 1) or
two (M = 2) B-frames in the first GOP of a sequence are
always forced backwards predicted.
Table 3 GOP
Notes
1. Undefined.
2. This GOP structure is defined as a Real Closed GOP
(RCG).
3. This GOP structure is defined as a Backward
Predicted Closed GOP (BPCG) or Non-Editable GOP
(NEG), selectable via the I
2
C-bus.
GOP
LENGTH (N)
REFERENCE FRAME DISTANCE (M)
01 2 3
1I
(1) (1) (1)
2
(1)
IP
(1) (1)
3
(1)
IPP IBP
(2) (1)
4
(1)
IPPP BIBP
(3)
IBBP
(2)
5
(1)
IPPPP IBPBP
(2) (1)
6
(1)
IPP...PP BIBPBP
(3)
BBIBBP
(3)
7
(1)
IPP...PP IBP...BP
(2)
IBBPBBP
(2)
8
(1)
IPP...PP BIBP...BP
(3) (1)
9
(1)
IPP...PP IBP...BP
(2)
BBI...BBP
(3)
10
(1)
IPP...PP BIBP...BP
(3)
IBBP...BBP
(2)
11
(1)
IPP...PP IBP...BP
(2) (1)
12
(1)
IPP...PP BIBP...BP
(3)
BBI...BBP
(3)
13
(1)
IPP...PP IBP...BP
(2)
IBBP...BBP
(2)
14
(1)
IPP...PP BIBP...BP
(3) (1)
15
(1)
IPP...PP IBP...BP
(2)
BBI...BBP
(3)
16
(1)
IPP...PP BIBP...BP
(3)
IBBP...BBP
(3)
17
(1)
IPP...PP IBP...BP
(2) (1)
18
(1)
IPP...PP BIBP...BP
(3)
BBI...BBP
(3)
19
(1)
IPP...PP IBP...BP
(2)
IBBP...BBP
(2)