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pythonstructpackpyaudio

How to use struct.pack/unpack with pyaudio correctly?

My goal is to unpack the string provided by pyaudio correctly to int16 for some modification and then pack it again to do the playback.

This is what i got so far (code copied from other post):

#data contains my string of interleaved int16 data

#this code should unpack it accordingly
# 1 short out of each 2 chars in data
count = len(data)/2
format = "%dh"%(count) #results in '2048h' as format: 2048 short
shorts = struct.unpack(format, data)

#here some modifications will take place but are left out to test packing

#now i need to pack my short data back to pyaudio compliant string
#i have tried the following with no success. just random noise
struct.pack(str(len(shorts)*2) + "s", str(shorts))

Now my question:

  • what would be the correct arguments for struct.pack to get my data back to pyaudio string?
Solution

  • Ok i found the answer elswhere:

    struct.pack("%dh"%(len(shorts)), *list(shorts))

    results in a correctly formatted string for pyaudio.

    Nevertheless i will happily accept any other answer, which explains the function calls and their correct usage!