Author Topic: fseq and fpp and 25ms  (Read 1186 times)

Offline dkulp

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fseq and fpp and 25ms
« on: February 15, 2014, 07:39:24 AM »

I noticed that the fseq file records the step time recorded in it.   I know for anything generated with xLights, that would always be 50ms.  Do any of the FPP devs know if the FPP would be OK with a 25ms file?  At least if all the outputs are e1.31? (I know pixelnet has limitations)   Mostly just curious if FPP even looks at that field right now or just assumes it's 50ms.   

For my e131Recorder thing, I may have it try recording at a faster rate.  That could help with some jitter.  Would also help if recording from Vixen or something that wouldn't have the normal 50ms timing.   

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Offline Materdaddy

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Re: fseq and fpp and 25ms
« Reply #1 on: February 15, 2014, 08:16:25 AM »
Currently FPP is hard coded to a refresh rate of 20 Hz, which means 50ms.

I'm not sure if there were ever plans to support other refresh rates, but the fact that one of the fields in the binary file format tells me David at least thought about including it ahead of time in case we ever wanted to support it.

Offline Skunberg

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Re: fseq and fpp and 25ms
« Reply #2 on: February 15, 2014, 09:05:49 AM »
I remember it being talked about at the very beginning, if I recall correctly there were technical issues and everyone involved at the time could live with 50 ms.

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Offline charleskerr

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Re: fseq and fpp and 25ms
« Reply #3 on: February 15, 2014, 11:12:15 AM »
The issue would be Pixelnet is 50ms.  So you can't have 25ms and do pixel net.
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Offline David Pitts

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Re: fseq and fpp and 25ms
« Reply #4 on: February 15, 2014, 02:21:24 PM »
It would be very easy to read the value in the file. I think it would work fine for E131 output. As stated it would not be good if you were outputting Pixelnet.
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Offline Skunberg

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Re: fseq and fpp and 25ms
« Reply #5 on: February 15, 2014, 02:29:39 PM »
But FPP wasn't designed just for pixel net, right?

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Offline MyKroFt

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Re: fseq and fpp and 25ms
« Reply #6 on: February 15, 2014, 02:33:02 PM »
It initially was designed for pixelnet/dmx to DLA products - it has since grown since then - but has stayed at the 50ms timing that most hardware/sequencers use by default

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Offline Timon

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Re: fseq and fpp and 25ms
« Reply #7 on: February 17, 2014, 03:39:30 AM »
Pixelnet could handle 25ms but to do so you would reduce the channel count on each output by half.

Offline charleskerr

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Re: fseq and fpp and 25ms
« Reply #8 on: February 17, 2014, 02:31:04 PM »
Pixelnet could handle 25ms but to do so you would reduce the channel count on each output by half.

But then it wouldn't be Pixelnet (Pixelnet isn't defined to have variable frame sizes in any of RJ's write-ups).  One could also double the Baudrate to 2Mb as well.

Anyway, I only mentioned it as many who starting using Falcon equipment were extending or enhancing their  current setup.  I then it would be great to support different rates, as many items such as shimmer, lip syncing, and fades look better at faster updates.

Offline Timon

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Re: fseq and fpp and 25ms
« Reply #9 on: February 19, 2014, 08:01:47 PM »
Pixelnet could handle 25ms but to do so you would reduce the channel count on each output by half.

But then it wouldn't be Pixelnet (Pixelnet isn't defined to have variable frame sizes in any of RJ's write-ups).  One could also double the Baudrate to 2Mb as well.

But it does not prohibit it. Anytime a sync byte is received the channel is reset back to the start so it would work.

The real question is what a E1.31 Pixelnet controller does if it receives packet at 40 frames per second? Logically it toss every other frame or overwrite the buffer.

Quote
Anyway, I only mentioned it as many who starting using Falcon equipment were extending or enhancing their  current setup.  I then it would be great to support different rates, as many items such as shimmer, lip syncing, and fades look better at faster updates.

What I'd do is accept the faster rates and send them at that rate over E1.31. I'd leave it up to the FPD to drop frames sent out as Pixelnet out and send at full rate when set as DMX out. Let's not forget Renard which the FPD could be programmed to send.

Offline corey872

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Re: fseq and fpp and 25ms
« Reply #10 on: March 08, 2014, 05:00:56 PM »
Just out of curiosity, where is the bottleneck?  Computer hardware is way faster than 2Mb/sec these days, the node datasheets talk of '1080 node cascades' and 'no any twinkle will be detected'.
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Offline David Pitts

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Re: fseq and fpp and 25ms
« Reply #11 on: March 08, 2014, 05:29:34 PM »
Just out of curiosity, where is the bottleneck?  Computer hardware is way faster than 2Mb/sec these days, the node datasheets talk of '1080 node cascades' and 'no any twinkle will be detected'.

The ability of the SSC to receive @2Mbs and send to pixels without missing any bytes coming in. On the Falcon16 and Falcon8 this is not a limitation.

Offline corey872

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Re: fseq and fpp and 25ms
« Reply #12 on: March 08, 2014, 09:47:11 PM »
Does that come down to the PIC or the ST485 transceiver?

I went back and looked up the specs for the ST485 transceiver on all the SSC versions and see it's listed at 2.5Mbps maximum.  The receiver chip I'm using on the new controller (MAX3280E) is guaranteed to 52Mbps minimum.  So if the issue is the 458, that would be cleared up on the new controller.




Offline David Pitts

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Re: fseq and fpp and 25ms
« Reply #13 on: March 08, 2014, 09:51:51 PM »

Does that come down to the PIC or the ST485 transceiver?

I went back and looked up the specs for the ST485 transceiver on all the SSC versions and see it's listed at 2.5Mbps maximum.  The receiver chip I'm using on the new controller (MAX3280E) is guaranteed to 52Mbps minimum.  So if the issue is the 458, that would be cleared up on the new controller.
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Offline corey872

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Re: fseq and fpp and 25ms
« Reply #14 on: March 09, 2014, 01:08:49 PM »
Interesting.   So the issue should be cleared up with the new micro controller.  I notice there is also an ST485ABN which is supposed to have a data rate of 30Mbps.  Looks like it should be a drop in replacement for the 2.5Mbps ST485BN.

 

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