Modifying software for fun and music, part 1

Author's Note: This is the first post in an experiment wherein I document my foray into deciphering and modifying a particular piece of open source software as I do it. My interest lies in whether the resulting posts a) are digestible, and b) provide additional insight into the "how" of the process. As such, these will undergo only cursory editing before being posted. Expect typos!

Update 9/14/2013: The second part of this post is finally available here!

A few months ago, I purchased one of these newfangled Internet-enabled televisions so I could stream movies from Netflix without having to plug my laptop into the TV every time. Since I didn't spring for a model with built-in wireless, I subsequently bought a nifty device from some big-name manufacturer, which lets me plug in an Ethernet device and acts as a wireless client on its behalf. This device happens to also let me stream music from said manufacturer's music application to my stereo via an 1/8" audio plug on the device. Pretty nifty stuff.

My main home computer is a desktop running Linux, and I don't want to boot my laptop every time I want to play some music (the whole point of the TV upgrade, right?). So I want an easy way to stream music from Linux to said device. Well, if you're familiar with audio under Linux, there's something like six different subsystems you can run: OSS, ESD, ALSA, Pulse, et cetera. Someone made a nice module for the Pulse audio subsystem that lets these devices act like virtual sound cards, which is great if you're running Pulse. But after an entire afternoon spent breaking and fixing my sound in an effort to shift from ALSA to Pulse, I decided this wasn't the solution for me.

Fortunately, someone else had the same idea and created a utility called raop_play a while back. This is a command line client that takes the IP address of the device we want to stream to and the filename of the audio file (e.g., MP3) to play. After a quick download and compile (okay, a moderately quick compile after installing a few dependencies and subverting build errors), it worked right out of the box. But it lacked a couple of things I wanted:

1. The command line only takes a single filename, even though there is an interactive mode with support for playing additional files. I'd like to specify an entire album up front.
2. Although the documentation claimed support for M4A files (which I happen to have a lot of by virtue of using said manufacturer's music store), I only got errors trying to play them. Playback of MP3 files also seems a bit buggy (playback sometimes stops prematurely). I'm thinking of incorporating a different decoding engine.

For today's post, I will focus just on the first item: playing multiple files. Armed with nothing but a compiler and an innate desire to make this software do what I want, this post is my log of trying to get this to work.