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RealAudio 8 Fixed-Point Decoder
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RealAudio 8 Fixed-Point Decoder

RealAudio 8 is an efficient, high-quality audio codec for low- to mid-bitrates (8 - 96 kbps). Both floating-point and fixed-point decoder implementations are available. The fixed-point decoder is optimized especially for ARM processors but can run on any 32-bit fixed-point processor which can perform a long multiply operation (two 32-bit inputs generating a 64-bit result).


Key Features

  • Pure 32-bit fixed-point implementation
  • High-quality C reference code for porting to new platforms
  • Optimized for ARM processors
  • Fully reentrant and statically linkable
  • Optional C++ API for compatibility with Helix clients
  • Designed for high performance and low power consumption in handheld and mobile devices

Technical Specifications

Average CPU Usage

Sample Rate
Channels
Bit Rate
Processor Model (1)
On-Device Tests (2)
ARM7TDMI
ARM720T
ARM9TDMI-REV2
ARM920T
ARM9E
StrongARM1
XScale
StrongARM 1110
11025 Hz
mono
11 Kbps
3 MHz
4 MHz
2 MHz
3 MHz
2 MHz
2 MHz
2 MHz
3 MHz
22050 Hz
mono
20 Kbps
6 MHz
7 MHz
5 MHz
6 MHz
5 MHz
5 MHz
5 MHz
7 MHz
44100 Hz
mono
32 Kbps
11 MHz
13 MHz
9 MHz
10 MHz
8 MHz
8 MHz
9 MHz
11 MHz
44100 Hz
stereo (dual)
96 Kbps
22 MHz
26 MHz
18 MHz
21 MHz
16 MHz
16 MHz
17 MHz
25 MHz
44100 Hz
stereo (joint)
96 Kbps
21 MHz
25 MHz
17 MHz
19 MHz
15 MHz
15 MHz
16 MHz
21 MHz

(1) Tested with ARMulator, simulated zero-wait-state memory
(2) Tested on iPaq 3650, 206 Mhz, PPC 3.0

Memory Usage

  • ROM = 28481 Bytes (const globals)
  • RAM = 20328 Bytes (heap)
    • Total Data Memory = 48809 Bytes
  • Code Size = 10000 Bytes (approximately - depends on compiler)

Frequently Asked Questions

Where is the code in CVS?

  • See the Helix RealAudio decoder project page: http://rarvcode-audio.helixcommunity.org

Where does the build system put the code in my local source tree?

  • datatype-restricted/rm/audio/codec/ra8lbr/fixpt/decoder

How does the build system decide whether to build the fixed-point or floating-point RealAudio 8 decoder?

  • If HELIX_CONFIG_FIXEDPOINT is defined in your profile, it will build the fixed-point decoder. Otherwise it will build the floating-point version.

Is there an optimized fixed-point version of the RealAudio 8 encoder too?


Copyright © 1995-2004 RealNetworks, Inc. All rights reserved. RealNetworks and Helix are trademarks of RealNetworks.
All other trademarks or registered trademarks are the property of their respective holders.



This page was last modified 03:03, 25 February 2008.This page has been accessed 6,899 times.
 

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Copyright © 1995-2014 RealNetworks, Inc. All rights reserved. RealNetworks and Helix are trademarks of RealNetworks.
All other trademarks or registered trademarks are the property of their respective holders.