[Speex-dev] Clicking noise using Speex built for TI C64+ DSP of DaVinci Processor

[Andy Ngo]

Hi,
 
I've been trying to get Speex to compile and run on the DSP of TI's new DaVinci System-On-Chip processor, which has both an ARM
(ARM926) and a DSP (C64+, based on the C6400).  I used the latest code (1.2beta) and followed the example in the speex-
1.2beta1/ti/speex_C64_test trunk to build the Speex library for the DSP.  Basically I have a loopback application on the ARM that
samples 8kHz 16-bit mono frames, gives them to the DSP to encode and decode them, and play the resulting decoded frames on the
headphone.  It seems to work but I get a clicking noise.  I have verified that this is not due to an underrun problem by doing the same
loopback bypassing Speex on the DSP side but added delay that is 3ms longer that than that of Speex encode and decode processing
times, and got smooth audio with no clicking noise.  Also, I fed the female.wav (posted on Speex site) through the Speex encoder and
decoder on the DSP and got a resulting decoded_female.wav that has a clicking noise; since I can't post the wav file on this group, I 
can send it to anyone who's interested in helping me.
 
Also, if I run the loopback application with Speex natively on the ARM side (not using the DSP), it works fine.
 
I don't know where that clicking noise is coming from.  Any advice/comments/suggestions?
 
Here's what's included in my config.h file for Speex (compiled with -DCONFIG_TI_C6X):
 
#define FIXED_POINT
#define FRAME_SIZE 160
#define DISABLE_WIDEBAND
#define MAX_CHARS_PER_FRAME (42/BYTES_PER_CHAR)
#define MANUAL_ALLOC
#define USER_MISC

Speex narrow band parameters I'm using:
    Quality: 2   /* 5950 bps */
    Enhancement: 0
    Vbr: disabled
    Complexity: 1
 
The DaVinci processor is relatively new and I can't seem to find anyone who has successfully used Speex on the DSP side.  Your help
is appreciated.  Thanks.
 
Regards,
Andy
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