Music transmission in a modern world - avoiding lag issues?

Pyjamas

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Hi everyone,

2nd year Christmas lights this year for me and I just was wondering how everyone goes about music transmission in a modern (iPhone/digital) world?

I will be doing my first display with music sequencing this year and I will get an FM transmitter, but, given this either requires people to be in their car (not great on my street due to it being narrow and not much parking) or bring a battery powered radio, are there any digital solutions people have discovered?

I have a set of speakers and an amp connected to my Raspberry Pi so I can play music live to people on the street but I obviously don't want to disturb neighbours so will likely only have this going for an hour a night.

Has anyone come up with any genius ideas that work? Live streaming the music via facebook maybe (likely to have a big delay)? some other app that people can download via a QR code?

Cheers!

Paul
 

djgra79

My name is Graham & I love flashing lights!
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You're right, any streaming platform (be it YouTube, Facebook Live, Twitch, etc) is going to introduce a HEAP of lag.
Even car digital radios have been known to introduce up to .5sec delay which is not an optimal experience (but many viewers may not notice that much, we as the creators will though!)
I too would be interested to see if anyone has any further thoughts of other ways to transmit audio, lag free.
 

Katekate

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Whenever this kind of thing gets brought up, it always gets shot down because of the lag problem. But Grahams comment about digital radios got me thinking - surely you could build something with less than 500ms of lag.

its never going to be perfect, but could it be good enough?

things like https://jamulus.io/ exist for doing live music practice, so surely the latency is not that bad.
 

Skymaster

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All digital solutions will increase latency. There is a certain amount of processing effort required to sample the analog signal, and convert it back to analog again. Typical products that do this in near-real-time are pretty darn expensive - the digital signal processors in them are intense. At near-realtime processing, one dropped packet, and they will glitch, they require a good network to operate.

Anything designed to operate over a network to consumer devices will have a decent (+2sec) jitter buffer in it to take care of any dropped packets, which will definitely occur with any wireless transmission. With digital radio, as mentioned above, these are in the order of 0.5sec, and you do get artifacting if there is an issue.
 

Kent

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So, I was planning to get a proof of concept working first, but since the topic has come up...

Since the audio is known in advance, there is no need to live stream it. A person would visit a website which would buffer the current song on the local device. It is then just a matter of syncing the current point in the current song. There are protocols which I believe will get it close enough not to be annoying (think NTP, however there is a WebRTC or similar standard too, don't have the link on me at the moment). It would also require a hook into FPP or similar to get an accurate timecode of where the display is at in the sequence.

I'm also completely ignoring any legal aspect of serving up copyrighted music at this stage...
 

Pyjamas

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So, I was planning to get a proof of concept working first, but since the topic has come up...

Since the audio is known in advance, there is no need to live stream it. A person would visit a website which would buffer the current song on the local device. It is then just a matter of syncing the current point in the current song. There are protocols which I believe will get it close enough not to be annoying (think NTP, however there is a WebRTC or similar standard too, don't have the link on me at the moment). It would also require a hook into FPP or similar to get an accurate timecode of where the display is at in the sequence.

I'm also completely ignoring any legal aspect of serving up copyrighted music at this stage...
Yeah the copyright music for public transmission is an issue (especially since it would be potentially online transmission). I has hoping if it could be done through a private stream (ie. via a link advertised on the front fence) that would help, obviously not eliminate the issue though
 

Skymaster

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It'd still be "public" though as it would need to be over the public internet - unless if you're going to set up and support a dedicated wifi network for this purpose (Which would be hell)
But hey, if you're using FM already, you have those same issues to deal with.

Edit: On further thoughts, even if it was a dedicated wifi. it's still very on the fence of being public broadcast, given the nature of it.
 

Kent

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I think it would be in the correct spirit of the law (if you have the correct licence for FM transmission), which would be enough for me personally.
 

Skymaster

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There are two legalities to music. 1. ACMA license for FM broadcasting, and 2. APRA license for public performance of music.
(1) Doesnt apply here because it's not over FM. #1 is related to using of the radio spectrum and interference etc.
(2) is the important one - it would also impact speakers in your front yard and also applies to music in a restaurant, music on hold on the phone, shopping centres, etc. It's to do with royalties to the content creators.
The bridge has been crossed before, most of the time they will wave it through, but it's worth asking the question. There are topics on it here.
 

fugley

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VLC media player or plex's new mp3 player on a local network .... lag will NOT be your friend
 

Cathelest

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Vivid had a drone show recently where they had an app to play the soundtrack, cinewav

Used in outdoor cinemas and drive thrus etc,

But as Kent suggested if there is a way to preload content and then have fpp or known time stamps it could work,

But would be easier if you had 1 long mashup sequence that fired at specific known intervals,
 

Notenoughlights

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I have a little bluetooth speaker with an AUX input that sits out in the front yard on one of my controller boxes, as well as an FM transmitter.
I'm not worried about digital radios and the delay they have, because there's nothing I can do about it, those people usually don't get out of their cars anyway and they're only there for the lights, and really only click at the last minute before leaving that the lights are actually timed to music.
I've not had one person come up to me to ask if I know about a delay between the music and lights, and the bluetooth speaker (because it's on AUX input) has no lag, and is at a low volume and has zero bass, anyone on the driveway can hear it and it doesn't bother the neighbours.
Most people are there for the lights, the music is an added bonus.
 
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