[Tutor] Python + Sound

[Corey Richardson]

On 02/12/2011 02:27 AM, Steven D'Aprano wrote:
> Corey Richardson wrote:
>> Hello Tutors,
>>
>> I'm working on a small script that compresses a file, sends it through
>> the telephone, and then receives and decompresses the file on the other
>> end. The compression is the easy part. The transmission is the hard
>> part. If anyone has worked with sound before, what do you recommend?
> 
> [snip of excellent help and advice]
> 
> http://en.wikipedia.org/wiki/TCP/IP_model
> http://www.howstuffworks.com/modem.htm
> http://en.wikipedia.org/wiki/Modem
> 
> and this may entertain, and help:
> http://www.joelonsoftware.com/articles/LeakyAbstractions.html
> 

Always been a fan of Joel's articles.

> 
> Of course this can be done -- otherwise we wouldn't have the Internet!
> But my guess is that doing this in pure Python will be so slow it will
> be almost faster for you to copy the file onto a USB stick and
> hand-deliver it to the other end. But if you insist...

Well, I'm still on my way to learning other languages, Java (which I
hate) and soon I begin my voyage onwards into C. I figure once I get
something working in a tool I know how to use well, I'll be able to get
it done in a tool that I /don't/ know as well.

> 
> * Your compressed file is a bunch of bytes. You need to come up with
>   a scheme for encoding that to sound. This needs to be reversible
>   and designed to work on low-fidelity systems (phone networks).
>   The obvious way is to have one tone represent a one-bit, and another
>   *very different* tone represent a two-bit. See also "frequency
>   modulation" and "amplitude modulation".
> 
> * Because of noise on the line, you need a scheme for error correction.
>   Google for "Error correcting codes" for more information.
> 
> * The sender and receiver need a way to notify each other that they
>   are ready to start transmitting data. This is called a handshake.
>   Otherwise, you risk losing data from the ends of the transmission.
> 
> You described this as "a small script" -- it might be so far, but by the
> time you finish it will be huge.
> 
>> I don't really want to use the wave module because it looks like too
>> much work.
> 
> Pardon me while I chortle :)

Merely one aspect of a larger whole that I expected to be much more
complex - I didn't want to spend all my time working on sound encoding.
I think I have much more realistic view on it now.

Thank you _so much_ for the help. I truly appreciate it, you've given me
much more perspective, and I'll need to consider carefully my next
steps. Probably quite a bit of time at the drawing board!