Reproduce PIPE functionality in IronPython
- by Muppet Geoff
Hi,
I am hoping some genious out there can help me out with this...
I am using sox to merge and resample a group of WAV files, and pipe the output directly to the input of NeroAACEnc for encoding to AAC format.
I originally ran the process in a script, which included:
sox.exe d:\audio\1.wav d:\audio\2.wav d:\audio\3.wav -c 1 -r 22050 -t wav - | neroAacEnc.exe -q 0.5 -if - -of test.m4a
This worked as expected. The '-' in the comand line translates as 'Pipe/redirect input/output (stdin/stdout)' - So Sox pipes to stdout, and NeroAACEnc reads from stdin, the | joins them together.
I then migrated the whole solution to Python, and the equivalent command became:
from subprocess import call, Popen, PIPE
runwav = Popen(['sox.exe', 'd:\audio\1.wav', 'd:\audio\2.wav', 'd:\audio\3.wav', '-c', '1', '-r', '22050', '-t', 'wav', '-'], shell=False, stdout=PIPE)
runm4b = call(['neroAacEnc.exe', '-q', '0.5', '-if', '-', '-of', 'test.m4a'], shell=False, stdin=runwav.stdout)
This also worked like a charm, exactly as expected. Slightly more convoluted, but hey :)
Well now I have to move it to IronPython, and the Subprocess module isn't available (the partial implementation that is, doesn't have Popen/PIPE support - plus it seems silly to add a custom library when there is probably a native alternative).
I should mention here, that I opted for IronPython over C#, because I am comfortable with Python now - however, there is a chance of moving it again later to C# native, and I am using IronPython to ease myself into it :) I have no C# or .net experience.
So far I have the following equivalent, that sets up the 2 processes:
from System.Diagnostics import Process
wav = Process()
wav.StartInfo.UseShellExecute = False
wav.StartInfo.RedirectStandardOutput = True
wav.StartInfo.FileName = 'sox.exe'
wav.StartInfo.Arguments = 'd:\audio\1.wav d:\audio\2.wav d:\audio\3.wav -c 1 -r 22050 -t wav -'
wav.Start()
m4b = Process()
m4b.StartInfo.UseShellExecute = False
m4b.StartInfo.RedirectStandardInput = True
m4b.StartInfo.FileName = 'neroAacEnc.exe'
m4b.StartInfo.Arguments = '-q 0.5 -if - -of test.m4a'
m4b.Start()
I know that these 2 processes start (I can see Nero and Sox in the task manager) but what I can't figure out (for the life of me) is how to string the two output/input streams together, as with the previous two solutions. I have searched and searched, so I thought I'd ask!
If anyone knows either:
How to join the two streams with the same net result as the Python and Commandline versions; or
A better way to acheive what I am trying to do.
I would be extremely grateful!
Many thanks in advance,
Geoff
P.S. A code sample based off the above would be awesome :) or a specific code example of a similar process that I can easily translate... this has broked my brayne.
