Python / Audio Conversion - I want to convert mp3 to wav

Question

Hi, Ive dabbled very little in actual coding, wrote one python app that these forums really helped me make, and Ive programmed in VBScript and SQL Server, but all academic, nothing for my own uses.  I need a program to convert mp3's to .wav's that can then be burned in 'Recorder' to burn the audio disc.  I know there are many scripts like this floating around, but I want to do my own, problem is, im lost.  I seem to have 2 main problems, getting the file names into a list or tuple,  and then actually running the commands to convert using a for loop using lame or mpg321.
this bash script uses mpg321 and sox,
#!/bin/bash
# allmp3wav
for i in *.mp3; do
echo "$i"
tgt=$(echo "$i" | sed -e "s/mp3/wav/")
mpg123 -b 10000 -s -r 44100 "$i" | sox -t raw -r 44100 -s -w -c2 - /var/cdrom/"$tgt"
done
This works fine and I understand the code.  Its saying for every file that ends in .mp3, run these commands, which do the coding.  The only problem is, this doesnt work in python, since its not pythong   Can someone give me a little bit of help?  Dont give me the program, or give me to much info, links would be great.
1 - Need to Get Directory
2 - Loop through all the .mp3 files and add them to an array.
3 - create a sub directory named "wav"
mkdir ~/wav
4 - copy all the mp3's to "wav"
cp ARRAy to wav/
5 - convert all .mp3's to wav
6 - delete the copied mp3's from .wav directory
for .mp3
rm
7 - tell me how many wavs were created.
for .wav
count + 1
That is just a rough flow chart of what I need to do, and as you can see its pretty bare as of now.  Also, I imagine to run mpg321 or lame commands, I need some sort of lame or mpg321 module?  Ive read the python wiki for for loops and lists and tuples, but I need more info.  Thanks, Justin.

Answer 1

Alright that helped alot, its almost working now, I am using Popen wrong still I assume, here is what I got.
import os
import subprocess
here = os.getcwd()
ctr = 0
for file in os.listdir(here):
    name, ext = os.path.splitext(file)
    if ext == ".mp3":
                p = subprocess.Popen("mpg123 -w " + name + ".wav " + name + ext , stdout=subprocess.PIPE, shell=True)
                ctr = ctr + 1
print ctr
That executes, but gives this error,
High Performance MPEG 1.0/2.0/2.5 Audio Player for Layers 1, 2 and 3
version 1.4.3; written and copyright by Michael Hipp and others
free software (LGPL/GPL) without any warranty but with best wishes
[readers.c:893] error: Cannot file [Beginning: No such file or directory
[mpg123.c:516] error: Cannot open [Beginning: File access error. (code 22)
[readers.c:893] error: Cannot file of: No such file or directory
[mpg123.c:516] error: Cannot open of: File access error. (code 22)
[readers.c:893] error: Cannot file Whats About to Happen] HWY 74.wav 01 [Beginni
ng of Whats: No such file or directory
[mpg123.c:516] error: Cannot open Whats About to Happen] HWY 74.wav 01 [Beginnin
g of Whats: File access error. (code 22)
[readers.c:893] error: Cannot file About: No such file or directory
[mpg123.c:516] error: Cannot open About: File access error. (code 22)
[readers.c:893] error: Cannot file to: No such file or directory
[mpg123.c:516] error: Cannot open to: File access error. (code 22)
[readers.c:893] error: Cannot file Happen]: No such file or directory
[mpg123.c:516] error: Cannot open Happen]: File access error. (code 22)
[readers.c:893] error: Cannot file HWY: No such file or directory
[mpg123.c:516] error: Cannot open HWY: File access error. (code 22)
[readers.c:893] error: Cannot file 74.mp3: No such file or directory
[mpg123.c:516] error: Cannot open 74.mp3: File access error. (code 22)
2
If i remove the subprocess popen, and just print name + ext and use the counter, it prints out both file name together, and how many mp3's it processed, 2.  So i know the program is doing what I want, im just converting wrong.  Thanks again.
here is whats in the directory, there is more then mp3's, so I know it is filtering the files properly thanks to your splittext.
justin ~/build/convert $  dir -ls
total 12104
  20 -rw-r--r-- 1 justin justin   17138 2008-05-19 17:59 00\ -\ Wretch.txt
   4 -rw-r--r-- 1 justin justin      44 2008-06-01 18:20 01
7588 -rw-r--r-- 1 justin justin 7768364 2008-05-19 17:59 01\ [Beginning\ of\ What's\ About\ to\ Happen]\ HWY\ 74.mp3
   4 -rw-r--r-- 1 justin justin      44 2008-06-01 18:20 02
4484 -rw-r--r-- 1 justin justin 4588063 2008-05-19 17:59 02\ Love\ Has\ Passed\ Me\ By.mp3
   4 -rw-r--r-- 1 justin justin    1284 2008-06-01 18:20 convert.py
justin ~/build/convert $
Last edited by axion419 (2008-06-01 22:23:32)