Why does the output of audioread() gives samples less than shown in audioinfo() ?

for some reason there is no problem in mac but in windows

[Star Strider]

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[madhan ravi]

Thank you for the response @Star Strider, i would really appreciate if you could confirm if you face the same problem with the attached file.

Answer 1

[Star Strider]

This is interesting!

The online Run feature computer uses Linux, and gives this result:

ZF = 'https://www.mathworks.com/matlabcentral/answers/uploaded_files/880055/VEHCar_Acceleration%20aston%20martin%20(ID%200600)_BSB.mp3.zip';
UZ = unzip(ZF);
ai = audioinfo(UZ{1})

ai = struct with fields:
             Filename: '/users/mss.system.cVYhtd/VEHCar_Acceleration aston martin (ID 0600)_BSB.mp3'
    CompressionMethod: 'MP3'
          NumChannels: 1
           SampleRate: 48000
         TotalSamples: 315600
             Duration: 6.5750
                Title: []
              Comment: []
               Artist: []
              BitRate: 320

[s,Fs] = audioread(UZ{1});
s_len = numel(s)

s_len = 314496

Windows 11 (run offlilne with the same code with R2021b) gives the following:

ai =

struct with fields:

Filename: 'C:\Users\vitha\Documents\MATLAB\FEF_Files\R & D\Answers & CSSM Problems\Temporary Projects\VEHCar_Acceleration aston martin (ID 0600)_BSB.mp3'

CompressionMethod: 'MP3'

NumChannels: 1

SampleRate: 48000

TotalSamples: 314496

Duration: 6.552

Title: []

Comment: []

Artist: []

BitRate: 320

s_len =

313968

I don’t have access to a Mac, so I have no idea what result it would give.

.

[madhan ravi]

much respect @Star Strider!, looks like the limitations of the OS

The method i came up with to overcome this issue was to convert the mp3 files after reading it and then before aduioinfo() converted that file to .wav format and by this way the number of samples is preserved.

[Star Strider]

Thank you!

I have not looked through the audioread documentation recently, so I went back just now and read through it. The Limitations section has interesting details that are directly relevant here.

Posting the conversion code to .wav format (or describing the process) would be helpful for others who read this.

[madhan ravi]

[y, Fs] = audioread('VEHCar_Acceleration aston martin (ID 0600)_BSB.wav'); % reading the mp3 file
audiowrite('VEHCar_Acceleration aston martin (ID 0600)_BSB.wav'), y, Fs); % converting the .mp3 file to .wav file
info = audioinfo('VEHCar_Acceleration aston martin (ID 0600)_BSB.wav') % audio info about the .wav file 

[Star Strider]

That’s what I thought.

There was always the possibility that some third-party application (not MATLAB) was used to convert it.

[madhan ravi]

Yes, for me using MATLAB is much easier so that I can analyse multiple signals within MATLAB environment.

Thank you once again @Star Strider for the help!

[Star Strider]

As always, my pleasure!