Unable to Stream More Than 2 DVB-T Channels Simultaneously

barhack

Hello TVheadend Community,

I hope someone can help me with an issue I've been experiencing. Despite not setting any limits or throttling my connection, I am unable to stream more than 2 DVB-T channels simultaneously. I have 2 streams running continuously, but whenever I try to launch a third stream, it fails to start.

I have checked my settings and configurations but haven't been able to pinpoint the problem. Could anyone advise on what specific areas I should look into or any potential solutions for this issue?

Thank you in advance for your assistance!

DaveH

What hardware are you using, especially tuners?

DeltaMikeCharlie

Check to see if there is an error message in your debug log.

Jonas Lang

A little more info on your hardware/OS setup would help along with possibly a log. It’s a crap shoot otherwise. It could be that the hardware is not coping too well with more than two streams. Who knows.

barhack

Thank you for your responses. I believe I've identified my mistake through some research. I am using a Raspberry TV Hat on my Raspberry Pi, and I just found out that it can only copy multiple channels if they are on the same "mux" or "multiplex."

Indeed, I noticed that the channels which do not work are on different muxes. When I test with channels on the same mux, everything works fine. It's as simple as that. It's unfortunate because I naively thought I could stream around twenty channels. I'm not 100% sure that this is the root of the problem, but it seems likely.

Thank you for pointing me in the right direction!

kbhasi

barhack
Yep, that's correct. As far as I know (and I may not be completely right about this), Tvheadend would instruct the tuner to tune to a specific UHF frequency, which contains a DVB-T or DVB-T2 multiplex (or ‘mux’ in Tvheadend terms), which then contains feeds that contain channels. Tvheadend would subscribe to those feeds to then receive and play/record the channel.

Because one tuner can access one multiplex, Tvheadend can play/record multiple channels on the same multiplex using the same tuner.

In order to access two multiplexes at the same time, two tuners are needed.

As an example with where I live, one TV network has 6 free-to-air channels which are spread across 3 DVB-T2 multiplexes, so if I were to watch/record all 6 channels, I'd need 3 tuners.

As far as I can tell, the Raspberry Pi TV HAT only has one tuner due to the Raspberry Pi platform itself only exposing one I²C connection on its standard GPIO header. If you want more TV tuners, you'd have to use USB TV tuners.

DaveH

Glad you solved it 🙂

DaveH

kbhasi the Raspberry Pi TV HAT only has one tuner due to the Raspberry Pi platform itself only exposing one I²C connection on its standard GPIO header.

I don't think that's completely correct, (a) because an I2C bus can handle multiple devices and (b) because the Pi has two I2C buses (GPIO pins 3&5 and 27&28). But other than that I think your explanation is correct.

barhack

kbhasi I've discovered the same thing... oh well, that TVHAT wasn't a huge investment. Do you have a USB tuner stick you could recommend? I suppose they also need to be plugged into a powered USB hub. I think I'll need to connect 5 USB sticks since I have 5 muxes to stream.

kbhasi

DaveH
That's interesting. When I first heard about the TV HAT, I was surprised that it had only one tuner, and when posting my reply I drew my conclusion about the single I²C bus from images I found when I ran a Web search for ‘Raspberry Pi GPIO pinout’.

DaveH

Only the original Model A and Model B have 26-pin GPIO and so a single I2C bus. All the others have 40-pin GPIO and have the second I2C on pins 27 & 28.