convert file from .wav to .mp3

I am using following code to extract just the audio in .wav format from a video in .avi format

file='take.avi';

file1='vipmen1.wav'; %o/p file name

hmfr=video.MultimediaFileReader(file,'AudioOutputPort',true,'VideoOutputPort',false);

   hmfw = video.MultimediaFileWriter(file1,'AudioInputPort',true,'FileFormat','WAV');

   while ~isDone(hmfr)

      audioFrame = step(hmfr);

step(hmfw,audioFrame);

   end

close(hmfw);

close(hmfr);

Then i am using the following code in gui for conversion :

global pl;  

global sf;  

[FileName,PathName]=uigetfile('*.wav')  

myFile=[PathName,FileName]

[mySong,sf]=wavread(myFile);

mp3write(mySong,sf,FileName)

it gives no error whatsoever but the mp3 file is not to be found.

Its not there in the working directory and the inital .wav file still is in same format.

[Jan]

Please format your code properly.

Answer 1

[Jan]

[FileName,PathName]=uigetfile('*.wav')
myFile=[PathName,FileName]
[mySong,sf]=wavread(myFile);
mp3write(mySong,sf,FileName)

Is this mp3write from the FileExchange? Please do not let us guess such important details. This function creates the file "Default_name.mp3" as default, when it is called with 3 inputs only.

What is the current directory during writing the file? Using absolute file names would be safer:

[dummy, Name] = fileparts(FileName);
mp3write(mySong, sf, FileName, fullfile(PathName, [Name, '.mp3']);

A general method to solve such problems is the debugger: Set a breakpoint in the line, which calls mp3write, then step into this function and see, what's going on.

[Niranjan Satam]

Jan Simon,

Apologies for the improper format.The mp3write is from FileExchange. Following is the directory during the writing.

C:\Users\SATAM\Documents\MATLAB

I did try using absolute file names but to no avail.Also the debugger isn't proving much useful. Is the Default_name.mp3 an actual formed and saved ? If yes , where ?

[Jan]

Look in the code of mp3write. The file name 'Default_name.mp3' is created there and the file should be saved to directory, which is active, when you start lame ! So please define an absolute file name for the created MP3. There is no better way to allow for an easy finding of the file later on:

mp3write(mySong, sf, FileName, fullfile(PathName, [Name, '.mp3']);

Do you see, that a 4th input is defined for mp3write?

UPS! Sorry, another search has shown, that there are 2 mp3write function in the FileExchange. So please, Niranjan Satam, tell us, which function you are using.

I'm convinced, that the debugger will be very useful, if it is used carefully.

[Niranjan Satam]

Jan Simon,

I was using mp3write by Alfredo Fernandez http://www.mathworks.com/matlabcentral/fileexchange/6152-mp3write-and-mp3read

Apparently there is no Default_name.mp3 in that code so obviously i was using the wrong file.

I am now using mp3write from following link

http://www.mathworks.com/matlabcentral/fileexchange/34455-mp3-player-gui

with this file, following was my main program

global pl;
global sf;  
[FileName,PathName]=uigetfile('*.wav')  
myFile=[PathName,FileName]
[mySong,sf]=wavread(myFile);
mp3write(mySong, sf,16);

Now a second file with the same name however with an explicitly visible .wav extension (common music files of .wav format do not show the extension explicitly) is formed in the same directory.When i hover the cursor,it reads MP3 format sound with size 0 bytes.The most important part is it shows fatal error in command window.Following is the command window output :

FileName =
  vipmen1.wav

PathName =
  C:\Users\Satam\Documents\MATLAB\

myFile =
  C:\Users\Satam\Documents\MATLAB\vipmen1.wav

File name = Default_name.mp3
Fixed bit rate, joint-stereo, 128 kb/s encoding
fatal error during initialization

Please note the temp file is formed and deleted as written in the code. Absolute naming wouldn't be necessary now since the file is formed in same directory.Am i correct on this one?

[Niranjan Satam]

Jan Simon,

I did find a way around this. All i did was go to the command window:

=>dos('cmd') =>lame -h vipemen1.wav output.mp3

this seems to work out for me. Thank you for all your help.Aprreciate it.