www.gusucode.com > dsp 案例源码程序 matlab代码 > dsp/ConvertSampleRateOfAudioSignalExample.m

    %% Convert Sample Rate of Audio Signal
% Convert the sample rate of an audio signal from 44.1 kHz (CD quality) to
% 96 kHz (DVD quality).

%%
% *Note*: This example runs only in R2016b or later. If you are using an 
% earlier release, replace each call to the function with the equivalent 
% |step| syntax. For example, myObject(x) becomes step(myObject,x).

fs1 = 44.1e3;
fs2 = 96e3;

SRC = dsp.SampleRateConverter('Bandwidth',40e3,...
    'InputSampleRate',fs1,'OutputSampleRate',fs2);

[L,M] = getRateChangeFactors(SRC);
FrameSize = 10*M;

AR = dsp.AudioFileReader('guitar10min.ogg', ...
    'SamplesPerFrame',FrameSize);
AW = dsp.AudioFileWriter('guitar10min_96k.wav', ...
    'SampleRate',fs2);

%%
% Run the system for 15 s. Release all objects.

tic
while toc < 15
    x = AR();
    y = SRC(x);
    AW(y);
end

release(AR);
release(AW);
release(SRC);

%%
% Plot the input and output signals. Use a different set of axes for each
% signal. Shift the output to compensate for the delay introduced by the
% filter.

t1 = 0:1/fs1:1/30-1/fs1;
t2 = 0:1/fs2:1/30-1/fs2;

delay = 114;

el1 = 1:length(t1)-delay;

el2 = 1:length(t2);
el2(1:delay) = [];

subplot(2,1,1)
plot(t1(1:length(el1)),x(el1,1))
hold on
plot(t1(1:length(el1)),x(el1,2))
title('Input')

subplot(2,1,2)
plot(t2(1:length(el2)),y(el2,1))
hold on
plot(t2(1:length(el2)),y(el2,2))
xlabel('Time (s)')
title('Output')

%%
% Zoom in to see the difference in sample rates. Use a different set of
% axes for each channel.

figure

subplot(2,1,1)
plot(t1(1:length(el1)),x(el1,1),'o-')
hold on
plot(t2(1:length(el2)),y(el2,1),'d--')
xlim([0.01 0.0103])
title('First channel')

subplot(2,1,2)
plot(t1(1:length(el1)),x(el1,2),'o-')
hold on
plot(t2(1:length(el2)),y(el2,2),'d--')
xlim([0.01 0.0103])
xlabel('Time (s)')
title('Second channel')