kghunt
Posts: 383
Joined: Sun Mar 04, 2012 9:28 am

Max number of USB Tuners

Wed Dec 14, 2016 1:57 pm

I have just set up one of my Pi 2's as a tvheadend server with a win Nova T ministick USB tuner. It only took around an hour and works a treat (most of the time was scanning & scraping).

As my Pi3 is currently in use as a retro console I was concerned that the Pi2 would not be man enough especially as I do not have the mpeg2 license for this pi. I was pleasantly surprised, even recording one show and streaming a recording the pi was only using 80Mb of RAM and not much CPU.

I have a second tuner on the way but my question is. How many tuners can you run off a Pi2/Pi3?

I currently have 1 tuner and 1 USB stick as my hardrive crashed every time it spun up (need external power).

fruitoftheloom
Posts: 19796
Joined: Tue Mar 25, 2014 12:40 pm
Location: Delightful Dorset

Re: Max number of USB Tuners

Wed Dec 14, 2016 2:33 pm

kghunt wrote:I currently have 1 tuner and 1 USB stick as my hardrive crashed every time it spun up (need external power).
If you have a Raspberry Pi 2B revision 1.1 (BCM2836 model) you can increase the USB total current from the default 600mA to 1200mA, though you will need a decent PSU and add the following to config.txt:

Code: Select all

max_usb_current=1
https://www.raspberrypi.org/help/faqs/#powerReqs

https://projects.drogon.net/testing-set ... berry-pi-b
adieu

My other Computer is an Asus CS10 ChromeBit running Chrome Operating System.
HP Envy 4500 Wireless Printer supported by HPLIP software in Raspbian Buster.
Raspberry Pi Model 2B v1.1

drgeoff
Posts: 9365
Joined: Wed Jan 25, 2012 6:39 pm

Re: Max number of USB Tuners

Thu Dec 15, 2016 12:51 am

kghunt wrote: As my Pi3 is currently in use as a retro console I was concerned that the Pi2 would not be man enough especially as I do not have the mpeg2 license for this pi. I was pleasantly surprised, even recording one show and streaming a recording the pi was only using 80Mb of RAM and not much CPU.
The MPEG-2 licence enables GPU hardware support when decompressing MPEG-2 video. Neither recording nor streaming involves decompressing the video. Therefore the presence or absence of an MPEG-2 licence is irrelevant.

(The use of video transcoding during recording or streaming would be a different matter.)

HiroProtagonist
Posts: 212
Joined: Sat Jun 29, 2013 9:45 am

Re: Max number of USB Tuners

Thu Dec 15, 2016 3:48 am

kghunt wrote: I have a second tuner on the way but my question is. How many tuners can you run off a Pi2/Pi3?
I currently have 1 tuner and 1 USB stick as my hardrive crashed every time it spun up (need external power).
As another user has mentioned, you need to investigate max_usb_current if you're running this stuff directly off the Pi USB ports.

There's no fixed upper limit to the number of USB tuners you can add, but you need to either keep within the limits of the Pi's ability to provide power, or connect them using powered USB hub. At some point you'd run into bandwidth problems on the Pi's USB, but you'd need quite a few tuners to get there.

I run 3 DVB-T tuners on a Pi 2 via a powered hub, I'm sure it could handle more.

kghunt
Posts: 383
Joined: Sun Mar 04, 2012 9:28 am

Re: Max number of USB Tuners

Sat Dec 17, 2016 7:11 am

Do you have any idea what the power draw on a USB tuner is?

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