Discussion on true Multi-room Solution (continued)

[darrenmason]

Certainly some potential in the PulseAudio stuff - particularly as it plugs in at the ALSA level and should be low impact to get the XinePlayer using it.
Wondering how it would work with Squeezeboxs etc.  Perhaps with a combination of PulseAudio through JACK to slimserver there is potential for getting MD's to synchronise with Squeezeboxs - at least good enough to solve the room transitioning problem.
Time to do some more reading...

[colinjones]

Darren

Not so sure that xine is going to be the issue, that seems to be transparent. The device template could certainly easily setup the basic parameters needed for PulseAudio to initialise in a basic sense..... however, I think that the PulseAudio device will likely need to be a DCE device so that it can respond to commands coming from the media plugin telling it to bifurcate and sync a stream... media plugin is the source for that coordination, not xine... it will effectively take the problem out of the hands of xine, and handle the audio at the virtual "hardware" layer, and so need to respond to some kind of DCE commands from media plugin... which in turn will need to be mod'd to know to actually send those commands to the PulseAudio device in the first place... that being said, all seems very possible and very interesting.....

[Purplexus]

Is it possible to do this within a core or a media director?

No.  It takes an RCA style input, not implementedable within LinuxMCE.

These devices are intended to be plugged directly into a car stereo and would require modification to use otherwise.  It's not meant meant for home system use, there are devices for that purpose, such as amplified matrix distribution systems.

Sorry I was assuming you knew what I was saying when I was refering to Modulators

In the cable industry a modulator usually takes in Composite Video and Left/Right Audio in order to pump its signal to a specific channel frequency.  It the case of a computer a 1/8 stereo mini headphone plug which is Y split out to RCA style plugs.

So yes the same although this time I am trying to make myself more clear.

[phenigma]

Sorry I was assuming you knew what I was saying when I was refering to Modulators

In the cable industry a modulator usually takes in Composite Video and Left/Right Audio in order to pump its signal to a specific channel frequency.  It the case of a computer a 1/8 stereo mini headphone plug which is Y split out to RCA style plugs.

Sorry Perplexus, I do understand the modulator and how it works in the cable industry for Audio-Video distribution.  This device works the same way only it simply modulates audio, no video, onto an FM radio frequency rather than a television channel frequency. 

My point was that there are likely more appropriate devices to use within a home as the device in question uses a 12V power source and has an antenna connector which is designed to plug directly into a car stereo, it is not a standard coax connection, hence the need to alter the device.  This is possible but I believe there are more appropriate devices to use within a home.

This is probably getting off-topic now for discussion within the dev section for multi-room audio within LMCE, I`d be happy to continue discussing this under another topic.

J

[krys]

I was not suggesting that we use the FM modulator I linked, only that maybe the technology could be used. Im sure there is some product out there that uses the same principle for home or business environments.
-Krys

[phenigma]

Not so sure that xine is going to be the issue, that seems to be transparent. The device template could certainly easily setup the basic parameters needed for PulseAudio to initialise in a basic sense..... however, I think that the PulseAudio device will likely need to be a DCE device so that it can respond to commands coming from the media plugin telling it to bifurcate and sync a stream... media plugin is the source for that coordination, not xine... it will effectively take the problem out of the hands of xine, and handle the audio at the virtual "hardware" layer, and so need to respond to some kind of DCE commands from media plugin... which in turn will need to be mod'd to know to actually send those commands to the PulseAudio device in the first place... that being said, all seems very possible and very interesting.....

There is development information available for building PulseAudio clients and modules that interface directly with PA rather than through the command line interface, this would be the ideal way to implement PA as a DCE device.  All stream syncing is taken care of by PA when you choose multiple outputs (local or networked).  Things should be transparent to the media application.  PA sinks (outputs) can be looped back as a source (input) which could be sent to a squeezebox simultaneously, although I don`t know if sync between PA and the squeezeboxes would be possible.  

Development information (much of which is above me) for PA is available at: http://pulseaudio.org/wiki/DeveloperDocumentation

With inexpensive MDs (My Eee Box B202 was $313.00 CDN) costing the same as a squeezebox ($299 US List), it would be great to have the functionality without the need to purchase an additional proprietary device (especially when the MD supports video output).

J

[Purplexus]

Has anyone been able to give pulse audio a try yet?

Very curious to see how it goes.

[Marie.O]

Has anyone been able to give pulse audio a try yet?

Very curious to see how it goes.

If you are so curious, why don't you give it a try yourself

*scnr*

[Purplexus]

Has anyone been able to give pulse audio a try yet?

Very curious to see how it goes.

If you are so curious, why don't you give it a try yourself

*scnr*

Unfortunate I dont have a linux box as of yet.  Will have in 2 more days. 

[Marie.O]

Will have in 2 more days. 

Please keep up us updated as to your findings.

btw: You can use VirtualBox to run Linux as well...

[david_halliday]

OK I have been lurking for a while,

I understand that DigiLinX cracked this problem in their Netstreams line. (http://www.netstreams.com/residential.aspx)

They can not only keep audio synced between zones but also between video playing through a ViewLinX and surround sound through SpeakerLinX.

I think they archive this by:

1) Minimize latency in all playback devices devices
2) Pass only uncompressed data over the wire (including video) using Multicasts
3) Rely on a high bandwidth gigabit switch

I think they may also time stamp all packets and use a local ntp style time sync between all devices on the net.

I'm not sure this is something LinuxMCE could or would want to offer but I thought I would at least point it out as food for thought.

Dave.

Ps. Passing uncompressed data only is the reason they are limited to 1080i at the moment. 1080p 60fps  requires more badwidth than gigabit. http://www.netstreams.com/commothertech.aspx?ID=3

 

[LegoGT]

OK I have been lurking for a while,

I understand that DigiLinX cracked this problem in their Netstreams line. (http://www.netstreams.com/residential.aspx)

They can not only keep audio synced between zones but also between video playing through a ViewLinX and surround sound through SpeakerLinX.

I think they archive this by:

1) Minimize latency in all playback devices devices
2) Pass only uncompressed data over the wire (including video) using Multicasts
3) Rely on a high bandwidth gigabit switch

I think they may also time stamp all packets and use a local ntp style time sync between all devices on the net.

I'm not sure this is something LinuxMCE could or would want to offer but I thought I would at least point it out as food for thought.

Dave.

Ps. Passing uncompressed data only is the reason they are limited to 1080i at the moment. 1080p 60fps  requires more badwidth than gigabit. http://www.netstreams.com/commothertech.aspx?ID=3

 

NetStreams:
About a year ago I wanted to take the plunge and buy a full NetStreams setup. On the plus side, the system is scalable, syncs perfectly, handles audio/video streams, supports bidirectional audio (intercoms), etc. After looking at the mechanics of an install I ran into a few issues:

First, you need to use their proprietary GigE switch and dedicate it to their traffic only. I imagine you could hang a few LinuxMCE boxes off it and not get in too much trouble but it's not a supported installation method.

Second, the components are really expensive. Also, you have to contact and hire a licensed NetStreams installer to even pretend to get the products in your hands. Any devices I've been able to find, otherwise, are old demo type units. Not really a DIY type solution.

PulseAudio
As you can tell, multi-room sync'd audio is important to me. The problem I can see happens when you start listening to music in one room, add another room, and then change the source in the original room. I'm not a pulseaudio expert but I can't think of how to transfer that source to originate from a new location without restarting the stream from a new machine. I don't think pulseaudio has the ability to solve this.

Keep in mind that pulseaudio won't give any success for streaming the video part for movies, TV, or concert videos -- only the audio stream.

Softsqueeze/Squeezeslave
At the moment I've been playing a lot with softsqueeze and having pretty good luck with it. This is exciting because I can start a softsqueeze client (or even a headless squeezeslave as a command line client) from pretty much any electronic device. I like this solution because it's heavily supported, the DCE device is already made, and can turn devices not able to run as full MD's into simple music players.

Network audio pipes
As another alternative, the core could cue up each audio stream and then allow each MD (or other capable audio streaming device) to just "tune in" and play. It would require a new DCE device but might be worth the effort since it's mostly shell scripting. Here's probably the best (and easiest to jump right in) intro into piping the audio around the house: http://www.debian-administration.org/articles/145


Let me know if you guys see any glaring reason to go one way or the other. I will be working on solving this regardless (for my own enjoyment!) but it would be nice if I take the path that's most useful to the rest of the community, too! Ideas?

[totallymaxed]

yes. My two boxes run _in perfect sync_ (yes, i have an "overlapping" area). If you look at their bugfixes, there were quite some improvements in latest firmwares (a few months ago). I've not tested it for days, but i had it running for some hours without getting out of sync.

br, Hari

Well after upgrading to Squeezecenter 7.3.2 and getting our SB Receiver & Boombox test units added to one of our 710 test Core's...then sitting and listening to a load of music I have to agree they sound 100% in sync. They are being served a single stream...but if you also select an MD then you get a separate stream for that MD. This latter scenario causes an out of sync situation between the Squeezeboxes and MD's. If you use all Squeezebox's then you have sync'd audio.

The Receiver is on a Gigabit CAT5 connection...while the Boombox is on Wifi...and they are still in perfect sync when playing a big (200+ track playlist) from the media Floorplan...and they have stayed in sync for several hours now too.

So this is very exciting news indeed!

Andrew

[Marie.O]

Andrew,

great news indeed.

Now, why not replacing xine as our audio player with softsqueeze?

That way, we might get near perfect sync more easily.

[totallymaxed]

Andrew,

great news indeed.

Now, why not replacing xine as our audio player with softsqueeze?

That way, we might get near perfect sync more easily.

Hmmm...that sounds like an interesting idea on the face of it... I will habe a chat with Uplink later about that.

Andrew