MUX Data Rate

[Joe69]

Hi Driver Developers,

I operate the TBS-5880 with Windows Driver 1.0.0.5 and noticed in TSReader or Transedit, that MUX data rate is always reported at approximately 35Mbps, regardless of real data rate. I can receive several different DVB-T MUXes here, for example
16QAM FEC 3/4 ~ 15Mbps
16QAM FEC 5/6 ~ 17Mbps
64QAM FEC 2/3 ~ 20Mbps

With my other DVB-T Device these data rates show up correctly in all applications, so I guess this is a TBS-Driver issue. I tried older drivers from initial 1.0.0.1, 1.0.0.3 and 1.0.0.4 also, no difference noticeable.

Maybe you could provide a fix for that issue?

Thank you in advance!
Best Regards, Joe

[steven]

Hi Joe69

This is because the speed is contained the NULL packet, Would you mind subtract the NULL packet rate
and have a check again.

Kind Regards

steven

[updatelee]

Here is what steven is talking about

updatelee@antec:~$ dvbtraffic
0000 16 p/s 2 kb/s 25 kbit
0001 15 p/s 2 kb/s 23 kbit
0010 15 p/s 2 kb/s 23 kbit
0011 16 p/s 2 kb/s 25 kbit
0014 0 p/s 0 kb/s 1 kbit
0100 15 p/s 2 kb/s 23 kbit
0101 7349 p/s 1349 kb/s 11054 kbit
0102 132 p/s 24 kb/s 198 kbit
0106 0 p/s 0 kb/s 1 kbit
0200 15 p/s 2 kb/s 23 kbit
0201 7705 p/s 1414 kb/s 11589 kbit
0202 131 p/s 24 kb/s 197 kbit
0206 0 p/s 0 kb/s 1 kbit
0300 15 p/s 2 kb/s 23 kbit
0301 5997 p/s 1101 kb/s 9019 kbit
0302 131 p/s 24 kb/s 197 kbit
0306 0 p/s 0 kb/s 1 kbit
0400 16 p/s 2 kb/s 25 kbit
0401 3801 p/s 697 kb/s 5716 kbit
0402 131 p/s 24 kb/s 197 kbit
0500 16 p/s 2 kb/s 25 kbit
0501 7073 p/s 1298 kb/s 10638 kbit
0502 131 p/s 24 kb/s 197 kbit
0506 0 p/s 0 kb/s 1 kbit
0550 1 p/s 0 kb/s 2 kbit
1fff 1360 p/s 249 kb/s 2046 kbit
2000 34099 p/s 6260 kb/s 51285 kbit
-PID--FREQ-----BANDWIDTH-BANDWIDTH-


1fff are null packets used as filler. 2000 is the total bitrate including null packets.

so this tp here has a total bitrate of 51.285mbit/sec with a databitrate of 49.239mbit/sec.

UDL

[Joe69]

Hi again,

and thank you for your explanations. So here are my rates from a MUX with around 15Mbps, as it is reported with other brand DVB-T Device:

PID HexPID StreamType kbps Percent
5020 0x139C MPEG2 Video 4231.54 28.32
5010 0x1392 MPEG2 Video 4193.64 28.07
5040 0x13B0 MPEG2 Video 3617.70 24.22
5023 0x139F AC3 Audio 470.36 3.15
5013 0x1395 AC3 Audio 470.36 3.15
8191 0x1FFF Null Packets 346.52 2.32
5015 0x1397 Teletext 263.50 1.76
5025 0x13A1 Teletext 263.42 1.76
5045 0x13B5 Teletext 263.34 1.76
5041 0x13B1 MPEG Audio 172.45 1.15
5021 0x139D MPEG Audio 172.45 1.15
5011 0x1393 MPEG Audio 172.45 1.15
18 0x0012 EIT 166.61 1.12
5046 0x13B6 Teletext 37.65 0.25
5024 0x13A0 Teletext 37.57 0.25
5014 0x1396 Teletext 37.57 0.25
503 0x01F7 PMT 45717 0.02
504 0x01F8 PMT 42430 0.02
502 0x01F6 PMT 42430 0.02
501 0x01F5 PMT 42430 0.02
1 0x0001 CAT 42430 0.02
0 0x0000 PAT 42430 0.02
21 0x0015 Network Sync 15738 0.02
17 0x0011 SDT 0.73 0.00
16 0x0010 NIT 0.16 0.00

You can see the null Packets 0X1FFF with approximately 2 percent. And this is what TBS-5880 reports on the same MUX:

PID HexPID StreamType kbps Percent
8191 0x1FFF Null Packets 20978.91 59.25
5020 0x139C MPEG2 Video 4480.48 12.66
5010 0x1392 MPEG2 Video 4122.21 11.64
5040 0x13B0 MPEG2 Video 3274.36 9.25
5023 0x139F AC3 Audio 470.09 1.33
5013 0x1395 AC3 Audio 470.07 1.33
5045 0x13B5 Teletext 263.27 0.74
5015 0x1397 Teletext 263.25 0.74
5025 0x13A1 Teletext 263.23 0.74
5041 0x13B1 MPEG Audio 172.36 0.49
5021 0x139D MPEG Audio 172.36 0.49
5011 0x1393 MPEG Audio 172.36 0.49
18 0x0012 EIT 166.50 0.47
5024 0x13A0 Teletext 37.61 0.11
5014 0x1396 Teletext 37.61 0.11
5046 0x13B6 Teletext 37.59 0.11
504 0x01F8 PMT 0.01 0.01
503 0x01F7 PMT 0.01 0.01
502 0x01F6 PMT 0.01 0.01
501 0x01F5 PMT 0.01 0.01
1 0x0001 CAT 0.01 0.01
0 0x0000 PAT 0.01 0.01
21 0x0015 Network Sync 2.46 0.01
17 0x0011 SDT 0.76 0.00
16 0x0010 NIT 0.15 0.00
20 0x0014 TOT 0.11 0.00

You can see, that according to the list there are more than 20Mbps Null Bytes reported, which result to an overall data rate of 35Mbps. And as I mentioned, every DVB-T MUX is reported with 35Mbps, regardless of the MUXes I tune to.
I can send you more examples... when tuning to a non active frequency with TBS 5880 the analyzer also shows up something:

PID HexPID StreamType kbps Percent ServiceName
8191 0x1FFF Null Packets 35420.63 100.00 N/A

You can see 35Mbps Null Bytes, where no signal exists at all. My other device shows no stream output in analyzer software.

So that brings me to the conclusion, that this is a TBS-driver issue.

Best regards,
Joe

[updatelee]

If there is no lock then you cant judge the results. The stv0900 driver will tell you TS rates like 250mbit/sec until it gets a lock. No lock = invalid results regardless. so disregard it.

Im not seeing a problem here though

"an overall data rate of 35Mbps. And as I mentioned, every DVB-T MUX is reported with 35Mbps"

where is the problem then? if all the pids add up to 35mbit/sec and thats whats reported. null packets are included in that calculation, thats pretty standard. If you dont want them factored in then thats a userland application issue, not a driver issue.

UDL

[Joe69]

Well, the problem is, that 35Mbps do not comply with the reality. For some reason with the TBS Card a massive amount of null bytes are reported, which aren't there and this adds up to 35Mbps.
Furthermore I don't think an application like TS Reader or Transedit reports garbage, because with all other devices the real, approved data rates show up. And as you can see for my example MUX this would be 15Mpbs, not 35Mbps.

You can calculate it by yourself - the data rate depends on bandwidth, modulation, FEC and guard interval. A DVB-T 16QAM FEC 3/4 GI 1/4 MUX with a channel width of 8MHz can in no case be capable of 35Mbps data rate.

Joe

[updatelee]

Ok I see what your saying, I missunderstood before.

First do you have another device to test just to confirm that there really isnt 20mbit/sec null packets. its high sure, but Ive seen worse.

It is suspect that every single freq you tune is always 35mbit/sec though, but I dont know dvb-t as its not here in NA, we use dvb-s and atsc. all similar but different as well. It would be nice to know the actual bitrate, but even if it did return the correct bitrate be aware that it would still include those null packets. If you only want data packets calculated then you just take the bitrate of 0x2000 and subtract 0x1fff. So again, its a userland application issue not a driver issue to calculate datarate, so even though the driver might be incorrectly reporting total bitrate, its still doable as is to calculate data bitrate. A driver should always return total bitrate, thats how all drivers work right now, its how all applications expect it currently.

UDL

[Joe69]

I mentioned twice , that with my other DVB-T Device the overall data rate shows up correctly in all applications. That's why I know about the correct data rates and I do know, that the 0x01FFF null packets count also for the overall data rate.

I guess, that the amount of Null Packets is calculated from the overall data rate 0x02000 subtracting the sum of all existent PID data rates. And it would be nice for the TBS-Device to report the real overall data rate 0x02000. That's what I asked for to correct.

Steven, would that be possible?

Kind Regards, Joe

[Joe69]

Hi Slo,

unfortunately I didn't get an answer from developers since my last post.

Best Regards,
Joe

[Thorium]

I can confirm the problem reported by Joe69. The problem of "added" null bytes (PID 8191) is existent with every mode using the 5880. For example, when I tune to a DVB-T Mux here with a netto rate auf 13.27Mbit/s, the box displays a Mux rate of 35Mbit/s and "fills up" the rest with null bytes. So you need to deduct the filled bytes to get the real null data rate of the mux.... it certainly is a bug of the driver.