Microchip Technology Inc

dsPIC DSC Speex Speech Encoding/Decoding Library


The dsPIC® DSC Speex Speech Encoding/Decoding Library performs toll-quality voice compression and voice decompression. The library is a modified version of the Speex speech coder and is optimized specifically for the dsPIC DSC family of Digital Signal Controllers (DSCs). It uses Code Excited Linear Prediction (CELP), which is a popular coding technique. The library supports both Narrowband and Wideband modes. It samples speech at 8 kHz or 16 kHz and compresses it to a selectable bit rate. The compressed speech data now requires less memory for storage or less bandwidth for communication.

Applications:

● Answering machines 
● Building and home security systems 
● Intercoms 
● Smart appliances 
● Voice recorders 
● Walkie-talkies
● Toys & Robots
● Any application using message playback

 

Features

The dsPIC DSC Speex Speech Encoding/Decoding Library has the following features:

● Simple user interface – only one library file and one header file.
● All functions called from a C application program
● Full compliance with the Microchip C30 Compiler, Assembler and Linker
● Highly optimized assembly code that uses DSP instructions and advanced addressing modes.
● Compact and concise API for easier integration with application
● Four modes:
● 8 kbps at 8 kHz sampling rate (Narrowband) – 16:1 compression ratio
● 11 kbps at 8 kHz sampling rate (Narrowband) – 11.63:1 compression ratio
● 9.8 kbps at 16 kHz sampling rate (Wideband) – 26.12:1 compression ratio
● 12.8 kbps at 16 kHz sampling rate (Wideband) – 20:1 compression ratio
● Library contains a Speex version optimized for 8 kbps mode
● Speex PC Encoding Utility for recording and encoding speech through a PC with output files generated for program memory, data EEPROM or RAM
● Audio bandwidth: 0-8 kHz with sampling rate of up to 16 kHz
● Multiple encoders and/or decoders can be instantiated
● Full-duplex and half-duplex operations
● Encoder and decoder can share scratch memories for optimal RAM usage
● Can be integrated with Microchip’s Noise Suppression, Acoustic Echo Cancellation and Line Echo Cancellation Libraries
● Library delivered on CD which includes:
● Sample demo applications with complete source code
● User’s guide
● HTML help files for PC Encoding Utility (PCEU)



Downloads

Description
Download
KB Size
Updated as of
dsPIC® DSC Speex Speech Encoding/Decoding Library User’s Guide
1146
10/31/2014
Speex setup
5417
10/31/2014
Decoded 16KHz audio output of dsPIC Speex library at 12.8KBPS
38
6/19/2015
Decoded 16KHz audio output of dsPIC Speex library at 9.8KBPS
38
6/19/2015
Decoded 8KHz audio output of dsPIC Speex library at 11KBPS
75
6/19/2015
Original Raw 16-bit Audio Input recorded at 8KHz_128KBPS
75
6/19/2015