DVBserver dvb-t; AV lagging.

[gibman]

When my 2 unicast clients tune to 2 different channels within the same mux, then the audio/video starts to lag like hell on both clients. If they tune to the same channel within the mux, then the problem disappears on the fly.

It's a 100mbit wired network, which is not the problem. File transfers etc. work flawlessly and speedy too.

 

The problem is quite easily reproduced.

 

Start an instance of DVBserver on ServerPC sharing a DVB-t device. In my case this is the Yakumo USB2 stick (with latest BDA drivers 1.0.0.42 and 5.9.19.0).

 

Here in denmark we currently have 4 (std. def.) channels in one mux.

Lets call it Mux1 has the following channels:

Ch1

Ch2

(we only need 2 channels to showcase the problem.)

 

Now on the client1 and client2, use a clean install of either 3.2.6.80 or one of the latest beta's - it doesn't really matter, since the bug is present no matter what client version you use.

 

Both clients are hooked up by a unicast connection.

Both clients can channel surf just fine - one client at a time that is .

So far so nice.

But now try to do this;

Client1 tune to Ch1 on Mux1

Client2 tune to Ch1 on Mux1

The 2 clients are now tuning into the same channel - still no problem - fine.

 

Ok, no we try and change the channel on one of the clients - the channel has to be in the same mux.

Like this:

Client1 tune to Ch1 on Mux1

Client2 tune to Ch2 on Mux1

Bang, now the audio and video is lagging so much that it is unwatchable.

(This lagging happens on both clients.)

 

Now change the channel again, this time on client1 ... like this;

Client1 tune to Ch2 on Mux1

Client2 tune to Ch2 on Mux1

Now the problem disappears.

(The problem is solved on both clients. They are now on the same channel)

 

/Elo

[Derrick]

Bang, now the audio and video is lagging so much that it is unwatchable.

..what do you mean by and ? If both lag the same amount, it will only cause an additional delay. Or do you have to wait until the next day

[gibman]

The audio has those annoying digital high screethcing noises. Like when a digital stream has errors. Awful sound. Tinitus here I come

Also the video is all choppy, pausing each few seconds. Sometimes the image is distorted too - the image is broken. You could say that it behaves a bit like when the bandwidth is insufficient. I will bet my money on the problem lies within the dvbserver.

 

It would be nice to have some feedback from people who are sharing a dvb-t device through dvbserver.

 

/Elo

Edited March 21, 2006 by gibman

[Derrick]

..could be an usb or network related problem as well. I only could try with dvb-s and pci or firewire.

[gibman]

Now consider the traffic between the server hosting dvbserver.exe and the USB2 enabled dvb-t device. When dvbserver has tuned into a mux1 b/c client1 requests ch1 from mux1. The whole mux1 data containing all 4 channels are transported from the dvb-t device over the USB2 interface, to the pc server host not only the ch1 data part...right ?

If this is a yes, then the USB2 bandwidth shouldnt be a problem here.

 

If no then consider that usb2 is 480 mbps. This should be able hold 2 different channels (each @ 4.5 mbit) easily.

Hell, it works when sharing my SS2/dvb-s channels, where some of them are over 5 mbit - and this is over a measely 100mbit LAN with 2 unicast clients. USB2 has more bandwidth.

 

So what is the problem here ?

Any guys out there willing to try this on their usb2 dvb-t sticks using dvbserver and 2 unicast clients ?? Beers on me, yeah

 

/Elo