spandsp: IMA ADPCM tests

spandsp 0.0.6

IMA ADPCM tests

# What does it do?

To perform a general audio quality test, ima_adpcm_tests should be run. The test file ../test-data/local/short_nb_voice.wav will be compressed to the specified bit rate, decompressed, and the resulting audio stored in post_ima_adpcm.wav. A simple SNR test is automatically performed. Listening tests may be used for a more detailed evaluation of the degradation in quality caused by the compression.

# How is it used?