TV-server, DVB-T USB 2.0, How many? (1 Viewer)

[Zapp]

Hi!

Thinking of going for dedicated TV-server with DVB-T USB 2.0 dongles.

Just made a test run with my old (very old) test rig, a Intel Celeron 1.7 GHz CPU, and noticed almost no CPU usage at all when tuning into a FTA channels. Sending the stream to a MP client worked without any problems.

I figure I'll need about 4 or 5 DVB-T USB 2.0 dongles connected to a USB 2.0 hub (only 2 ports on motherboard) to cover all recordings and live TV needs around the house.

Today I run a ASRock ION330, both client and server, with 3 DVB-T USB 2.0 dongles without any problems.

Every dongle can handle 2 tuned channels at the same time provided that the channels are on the same MUX.

Q: What will be the bottleneck here, CPU load, USB 2.0 transfer rate, RAM memory, network bandwidth? How many DVB-T USB 2.0 dongles can one USB 2.0 port handle?

/Jonas...

 

[funkstar]

In theory, the device limit of a USB controller is 127 devices, not including hubs and repeaters. If multiple ports share the same controller the number of devices is combined between the two.

As for how many you can practicaly have, well I'm not sure. DVB-T is great, as you have seen it required very little processor overhead for recording as all MediaPortal is doing is taking the video and audio streams from the MUX and dumping it to disk. No video or audio processing is done at this point. The data stored on disk is exactly the data sent by the broadcaster.

I would have said that the USB controller and the drivers would be the limiting factor. USB drivers have a tendancy to be pretty terrible (not all the time, but often enough). While a bunch of tuners may work just fine, you could easily mess things up by adding another device that doesn't like anythign else.

 

[tompa]

Zapp

just for ur info, im running two Hauppauge Nova-TD (and have tried three) without any problems. This is on a old P4 machine.

regards,
/tompa

 

[Zapp]

Hi!

Thanks for the answers. I'll go ahead and implement this then. It does mean that I have to rewire my rooftop antenna, but why not? This is what we live for, right? Testing what works and what does not.

Hopefully I don't trip and fall down... if safe and sound back on ground I'll get back and report my findings.

CU...


/Jonas...

 

[Zapp]

A bit late but still...

I now have a multiseat MP set-up with 3 clients and 1 server. Server has 4 cheap USB DVB-T sticks. In good conditions, all sticks can receive any channel that I subscribe to. Now, my antenna is not that great so the good conditions are rare.

Funny thing, my sticks are from Kjell & Co here in Sweden. 2 of them (Roxcore) costed me about twice as much and the other two (Plexgear).

Now, since you always get what you pay for, right? It bothers me that the reception is always failing on the costly ones and the two really cheap ones just works any day of the week!

BTW: No, it's not the antenna cord that is the problem, I've switched them around and it's always the same two that are failing!

/Jonas...

 

[pilehave]

Question is, do you need 4-5 tuners? Do you receive TV from that many transponders? MediaPortal can tune/timeshift/record more than one channel from each tuner, as long as they are on the same transponder (MUX).

In Denmark we have 5 different MUX's in service, covering our MPEG2 public service (MUX 1), MPEG4 public service (MUX2) and Boxer MPEG4 (MUX 3-5).

I can see from you post that you are aware of this, just didn't read it right the first time, sorry

 

[tompa]

Now, since you always get what you pay for, right? It bothers me that the reception is always failing on the costly ones and the two really cheap ones just works any day of the week!

It doesn't surprise me, have u ever seen a specification for sensitivity (bit error rate for low signals levels) on these type of products? Even though they have the same chip/hardware they probably do there own firmware, and that will result in different behavior.

I have the Plexgear from Kjell also, and its performing as good as my Hauppauge cards.

Thanks for ur info!
/tompa

 

[Zapp]

MediaPortal can tune/timeshift/record more than one channel from each tuner, as long as they are on the same transponder (MUX).
...
I can see from you post that you are aware of this, just didn't read it right the first time, sorry

Well, they are not on the same MUX so I don't have much choice when the family can't decide on just one channel for the evening (hint: 3 clients).

I do receive the Danish FTA channels also!

/Jonas...