Philips Semiconductors
Integrated MPEG AVGD decoders
Preliminary specification
SAA7215; SAA7216; SAA7221
• Vertical scaling with fixed factors 0.5, 0.75, 1 or 2;
factor 0.5 realizes picture shrink. Factor 2 can be used
for up-conversion of pictures with 288 (240) lines or
less; factor 0.75 is used for letterbox presentation.
• Horizontal and vertical scaling can be combined to scale
pictures to 1⁄4 of their original size, thus freeing up
screen space for graphic applications like electronic
program guides
• Non full screen MPEG pictures can be displayed in a
box of which position and background colour are
adjustable by the external microcontroller; structured
background is available as part of the graphic features
• Nominal video input buffer size for MP at ML 2.7-Mbit
• Video output may be slaved to internally (master)
generated or externally (slave) supplied
HV synchronization signals or CCIR-656 contained
synchronization signals. The position of active video is
programmable. Display phase is not affected by MPEG
timebase changes.
• Decoding and presentation can be independently
handled under CPU control
• Various trick modes under control of external
microcontroller:
– Freeze field/frame on I- or P-frames; restart on
I-picture
– Freeze field on B-frames; restart at any moment
– Scanning and decoding of I- or I- and P-frames in a
IBP sequence
– Single step mode
– Repeat/skip field for time base correction
– Repeat/skip frame for display parity integrity.
• Synchronization modes: DTS controlled, DTS free
running, software controlled, buffer controlled
• DTS register can be set via external controller;
programmable processing delay compensation.
MPEG-2 audio features
• Supported audio sampling frequencies:
48, 44.1, 32, 24, 22.05 and 16 kHz
• Independent channel volume control and programmable
inter-channel crosstalk through a baseband audio
processing unit
• MPEG audio decoder
– Decoding of 2 channels, layer I and II MPEG-1 audio
and low sampling frequency extension of MPEG-2
– Supports for mono, stereo, intensity stereo and dual
channel mode
– CRC error detection with automatic mute
– Constant and variable bit rates up to 448 kbit/s
– Selectable output channel in dual channel mode
– Storage of last 54 bytes in ancillary data field
– Dynamic range control at output.
• Muting possibility via external controller; automatic
muting in case of errors
• Generation of ‘beeps’ with programmable tone height,
duration and amplitude
• Linear PCM decoding
– Support for up to 8 channels linear PCM elementary
audio streams
– Supports for 8, 16, 20 and 24 bit/sample
– Supports for bit rates up to 6.144 Mbit/s
– 96 kHz LPCM samples will be mapped to a 48 kHz
multi-channel format
– Volume control for linear PCM samples in three
steps: −6, −12 and −18 dB.
• Burst-formatting for interconnection with an external
multi-channel decoder
– AC-3 elementary streams (IEC1937)
– MPEG-2 multi-channel streams in ES or PES format
– Output via the digital audio output or the IEC 958
output.
• Output stage
– Global control for volume and balance
– Serial multi-channel digital audio output with 16, 18,
20 or 22 bits per sample, compatible either to I2S or
Japanese formats; output can be set to high
impedance mode via the external controller
– IEC958 (Serial SPDIF) audio output; output can be
set to high impedance mode
– Clock output 256 or 384 × fs for external
DA converter or clock input; output can be set to high
impedance mode.
• Audio FIFO in external SDRAM; programmable buffer
size, at least 64 kbit is available
• Synchronization modes: PTS controlled, PTS free
running, software controlled, buffer controlled
• PTS register can be set via external controller;
programmable processing delay compensation.
Background colour
• 24 bit YCbCr colour.
2000 Jan 31
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