Author Topic: Understanding the Master / Slave roles  (Read 407 times)

Offline z0mbieSt0mp

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Understanding the Master / Slave roles
« on: May 11, 2017, 05:34:20 PM »
Hello all,


This Halloween will be my fourth year doing light shows.


In previous years I ran a Vixen/Arduino setup on a homebrew 16 relay board and 4 RGB strips


This year, I have entered the Falcon's realm and have 3 RP3's and 2 Arduino Megas using 88 channels and all RGB lighting and some triggered halloween props.


My setup plan is as follows: Master Pi connected to a 22" monitor for showing slides and images (tune to, song info, etc.)


Pi #2 (slave) runs the lighting and some props


Pi #3 (slave) will run video to a projector


From my understanding after reading thru the manual a few times, I need to plug my FM transmitter into my Master to run all audio. (This is the pi running the monitor display)


Now, here's where I get confused...


If my playlist contains a video that I want played on the 3rd pi (projector) won't the same video end up playing on the master's monitor?


If YES, how can I stop this from happening, as I only want the monitor to display my "signs" and not video.


Thanks in advance!

Offline CaptainMurdoch

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Re: Understanding the Master / Slave roles
« Reply #1 on: May 17, 2017, 03:00:14 PM »
Is your sequence synchronized to the audio in the video or are you using audio on the master?  You can play a mp3 file on the master and the video should stay in sync although there will be a brief period at the beginning of the video where the audio and video are out of sync.  I have some plans to work on getting better sync at initial startup, but I haven't had a chance to implement yet.
-
Chris

Offline z0mbieSt0mp

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Re: Understanding the Master / Slave roles
« Reply #2 on: May 19, 2017, 06:37:40 PM »
My show is mostly music and lights, with videos mixed in

For example a song/light sequence, then a video plays on my video screen, then back to song/light sequences. Never really playing both simultaneously.

However, before I did it with just Vixen and Arduinos and had to time the video and start of the show perfectly... major pain in the butt

Now with the FPP, it will be easier to keep everything synced up.

My plan was to rip the audio and make a sequence to play on the master, while the actual video played on another PI into my projector.

Question is, how do I keep the video from playing on the monitor on Master (as outlined above)? Do I just NOT include the video file on that Pi?

Offline jbsquires

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Re: Understanding the Master / Slave roles
« Reply #3 on: May 20, 2017, 05:22:12 AM »
If the video contains audio: Create a mp3 audio file from video and put that on master the video file on slave.

Offline jaysdisaster

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Re: Understanding the Master / Slave roles
« Reply #4 on: May 20, 2017, 10:50:34 AM »
When there is a video file on a slave of the same name as a audio file on the master the slave will play the video on it's hdmi output.
I am not sure how you are sending data to your 22" monitor but you might want to use the virtual matrix output for the master where as the pi outputs a matrix from your sequence to the hdmi port

Offline z0mbieSt0mp

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Re: Understanding the Master / Slave roles
« Reply #5 on: May 20, 2017, 06:46:01 PM »
Thank you

Offline z0mbieSt0mp

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Re: Understanding the Master / Slave roles
« Reply #6 on: May 20, 2017, 06:47:09 PM »
I am not sure how you are sending data to your 22" monitor but you might want to use the virtual matrix output for the master where as the pi outputs a matrix from your sequence to the hdmi port


HDMI

Offline z0mbieSt0mp

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Re: Understanding the Master / Slave roles
« Reply #7 on: May 21, 2017, 09:33:57 AM »
Ok, so I tested this out in my living room.


With the master running audio only, it is roughly half a second behind the video... no matter how long it ran, the audio never caught up (video was roughly 4 minutes long)


I switched master to display to the projector, audio sync is no longer an issue.

Offline z0mbieSt0mp

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Re: Understanding the Master / Slave roles
« Reply #8 on: May 21, 2017, 02:30:21 PM »
more findings on this one:

Master running audio, Slave running video

ON MY PLAYLIST: If I select media and sequence and use the MP4 (video) as the source, it stays in sync with the video

Offline z0mbieSt0mp

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Re: Understanding the Master / Slave roles
« Reply #9 on: May 21, 2017, 02:38:37 PM »
Sorry to keep posting back, just thinking ahead if this info could help others.

I imported the VIDEO file in Audacity and added exactly one HALF of a second of silence in the beginning. Then I exported the MP3 file.

I created a playlist with a blank sequence and using the MP3 as the "media" and now it's all sync'd back up

Running Audio on Master (MP3) and Video on a Slave (MP4) connected to my TV

EDIT: Also just adding the MP3 as "Media Only" is also working without problem

Offline CaptainMurdoch

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Re: Understanding the Master / Slave roles
« Reply #10 on: May 23, 2017, 12:06:28 PM »
I imported the VIDEO file in Audacity and added exactly one HALF of a second of silence in the beginning. Then I exported the MP3 file.

I created a playlist with a blank sequence and using the MP3 as the "media" and now it's all sync'd back up

Thanks for looping back and posting your test results.

The MP3 and MP4 players are totally separate programs, so I can imagine that sync might be off a little.  We have also found that saving/recreating a MP3 in Audacity adds a tiny bit of silence at the beginning each time you load/save, so you may find a need to chop some blank space if you ever load the file and save it again.

 

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