STM7710

Architecture

19/23

2.14.2

Audio decoder

The audio decoder receives the compressed audio (PES or ES) or PCM audio stream on its

main input. For compressed data it performs PES parsing, PTS extraction, multichannel

decoding and downmixing. At the same time, it formats the multichannel compressed data

stream for output over the S/PDIF interface for external decoding. Decoded multichannel

audio is downmixed before emerging as downmixed stereo or Dolby Pro Logic® encoded

audio. True Surround XT® post processing can be applied. PCM audio is passed straight

through.

Decoding of MPEG-1 layers I, II, Dolby® Digital and AAC stereo are supported at sample

rates of 32 kHz, 44.1 kHz and 48 kHz.

The decoded/downmixed channels can be mixed with PCM files from the 2nd input which

the audio decoder has sample rate converted.

The audio decoder can generate programmable tones for dish alignment.

The audio decoder generates the following:

●

Main 2-channel output: the left and right decoded/downmixed channels (L/Lt, R/Rt) with

PCM file mixing.

●

S/PDIF output: a digital audio stream selected from one of the following:

–

IEC61937 formatted compressed audio received on the audio decoder’s main

input,

–

IEC60958 formatted version of the main 2-channel output.

2.14.3

Audio output interfaces

The audio output interfaces from the STM7710 are:

●

S/PDIF interface. This outputs the S/PDIF output from the audio decoder.

●

Analog stereo output from integrated 24-bit DACs. This outputs the main 2-channel

output from the audio decoder.

2.15

FDMA controller

The STM7710 has a multichannel, burst-capable direct memory access controller that

supports the following.

●

Fast 2D unaligned memory to memory transfers of graphics and stills.

●

Real-time stream transfers to and from memory with or without pacing. These channels

are suitable for transfers with internal or external peripherals and for audio and video

stream transfers within the STM7710.

●

Two external pacing signals for paced transfers to and from external peripherals.