Hi Folks,
We have the mad library running on the new STR912 processor; 96MHz ARM9 core.
We are using a small CPLD to bridge between the SSP serial port and a CS4431 stereo dac.
We have an I2C silicon oscillator being used so we can set any sample rate we want. Currently, its working at 22.05KHz. We haven't change the sample rate yet.
I want to be able to run 8Khz to 48KHz MP3s. Is there anything in the mad decoder that would prevent decoding MP3s within this range? We don't have a sample issue with our hardware since we can set any sample rate we want.
Thanks
Steve Spano, President
steve@fl-eng.com
Finger Lakes Engineering
607-277-1614 x223
www.fl-eng.com http://www.fl-eng.com/
On Sep 7, 2007, at 9:57 AM, Steve Spano wrote:
I want to be able to run 8Khz to 48KHz MP3s. Is there anything in the mad decoder that would prevent decoding MP3s within this range? We don’t have a sample issue with our hardware since we can set any sample rate we want.
MAD supports all MPEG audio sampling frequencies, namely 8000/11025/12000 (MPEG 2.5), 16000/22050/24000 (MPEG-2 LSF), and 32000/44100/48000 (MPEG-1) Hz.
Keep in mind the bitstream determines the sample rate you get from MAD. If you want to output PCM at some other rate, you'll have to resample it first.
Hi Rob,
Great - thanks! I see the call, something like set sample rate. It just goes to a debug trace and I see it decoding a file at 22050. So we will hook that into the silicon oscillator setup.
We are also going to run MAD on the Xilinx Microblaze later this month as well.
I have another issue with compiling with the FPM_ARM; but I am working on resolving that. Right now I am using FPM_DEFAULT.
So I may ask a few other questions. For the STR912 implementation, we actually want to run two instances of MAD, in mono mode, and then have one MP3 goto the left channel and the other the right; assuming the sample rates match.
It doesn't look like MAD performs on the fly resampling; which is fine. We may add it later.
Thanks
Steve Spano FLE
-----Original Message----- From: mad-user-bounces@lists.mars.org [mailto:mad-user-bounces@lists.mars.org] On Behalf Of Rob Leslie Sent: Friday, September 07, 2007 1:14 PM To: mad-user@lists.mars.org Subject: Re: [mad-user] mad decoder sample rates
On Sep 7, 2007, at 9:57 AM, Steve Spano wrote:
I want to be able to run 8Khz to 48KHz MP3s. Is there anything in the mad decoder that would prevent decoding MP3s within this range? We don't have a sample issue with our hardware since we can set any sample rate we want.
MAD supports all MPEG audio sampling frequencies, namely 8000/11025/12000 (MPEG 2.5), 16000/22050/24000 (MPEG-2 LSF), and 32000/44100/48000 (MPEG-1) Hz.
Keep in mind the bitstream determines the sample rate you get from MAD. If you want to output PCM at some other rate, you'll have to resample it first.
-
Rob Leslie -
Steve Spano