Forked for self-learning, add more comments to explain the code.

Additionally support the MP3 format.

A command line slow-scan television decoder that works on audio files rather than reading a soundcard (like most other decoders). Currently supports the following modes:

• Martin 1, 2
• Scottie 1, 2, DX
• Robot 36, 72

$ git clone https://github.com/colaclanth/sstv.git

$ python setup.py install

$ sstv -d audio_file.wav -o result.png

• SSTV specification/timings - The Dayton Paper