[200] Shairport

[jimi00]

This program emulates an AirPort Express for the purpose of streaming music from iTunes and compatible iPods. It implements a server for the Apple RAOP protocol. This is different from the Airplay Server which only allows video and slideshows to stream.

Details here: https://github.com/albertz/shairport
Version 0.5 is here downloadable here: https://github.com/albertz/shairport/downloads

It has grown to rely on a simple perl script with dependencies to:
* openssl
* libao
* avahi (Bonjour for linux)
* Perl 5.10 or higher with the following modules:
- HTTP::Request
- HTTP::Message
- Crypt::OpenSSL::RSA
- IO::Socket::INET6
all of which can be installed from opkg (local).

I have tried installing each dependency but ran into an error while the avahi daemon was launching. I tried to run the perl script anyway only to run into an error, this time because I had failed to properly install the required perl modules.
If someone has the background to resolve these two issues we could certainly have a working version on the PCH platform.

[jimi00]

I'd really like to get this project working. Here's a little "up" with some news. Apple Lossless Audio Codec is now open source (Apache license) http://alac.macosforge.org/. This could prove important for this project but also for others (i.e. MPD).

[shadowcode]

(10-28-2011 09:02 AM)jimi00 Wrote:  I'd really like to get this project working. Here's a little "up" with some news. Apple Lossless Audio Codec is now open source (Apache license) http://alac.macosforge.org/. This could prove important for this project but also for others (i.e. MPD).

Sorry to disappoint you, but, we can already decode ALAC with libavcodec (from FFmpeg), that's not really the problem.

The problem is that there's no way of outputting sound. On the A110 MPD uses an audio output plugin written by AlanH (who has access to the Sigma SDK), if I remember correctly (I don't own one) the MPD package for the 200-series is configured to transcode the audio and stream it, while invoking gaya (or whatever's it called now) to receive that stream. I'm not sure what that means for audio quality, though.

Arguably, the same trick can be done by modifying shairport to do something similar, but that's quite a lot of work.

[jimi00]

(10-28-2011 10:06 AM)shadowcode Wrote:  

(10-28-2011 09:02 AM)jimi00 Wrote:  I'd really like to get this project working. Here's a little "up" with some news. Apple Lossless Audio Codec is now open source (Apache license) http://alac.macosforge.org/. This could prove important for this project but also for others (i.e. MPD).

Sorry to disappoint you, but, we can already decode ALAC with libavcodec (from FFmpeg), that's not really the problem.

The problem is that there's no way of outputting sound. On the A110 MPD uses an audio output plugin written by AlanH (who has access to the Sigma SDK), if I remember correctly (I don't own one) the MPD package for the 200-series is configured to transcode the audio and stream it, while invoking gaya (or whatever's it called now) to receive that stream. I'm not sure what that means for audio quality, though.

Arguably, the same trick can be done by modifying shairport to do something similar, but that's quite a lot of work.

Thank you for your reply. By the fact that the Airplay software was ported very quickly and outputs video (and audio), I assumed porting Shairport would be fairly easy. Or am I missing something?

[Grael]

(10-28-2011 10:06 AM)shadowcode Wrote:  if I remember correctly (I don't own one) the MPD package for the 200-series is configured to transcode the audio and stream it, while invoking gaya (or whatever's it called now) to receive that stream. I'm not sure what that means for audio quality, though.

A bit off topic, but... audio quality is very good, it's lossless transcoding. The problem is stability... (when skipping to next track, moving in the current file)

[popcornmix]

(10-28-2011 10:29 AM)jimi00 Wrote:  Thank you for your reply. By the fact that the Airplay software was ported very quickly and outputs video (and audio), I assumed porting Shairport would be fairly easy. Or am I missing something?

Airplay is in some ways simpler as you end up with a URL to a video file you can just pass to the internal media player.

With shairport you just end up with sequences of samples, and you need some way of outputting them. There's no accessible audio driver to send them to.

The best solution I could think of is writing a web server that generates on the fly (by decoding the ALAC) what looks like a wav file, and get NMT to play from that URL. That's not an easy project.

As shadowcode says, there may be something in MPD to help, but I don't know much about it.