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Re: [Discuss-gnuradio] DVB-T/T2

From: Bogdan Diaconescu
Subject: Re: [Discuss-gnuradio] DVB-T/T2
Date: Thu, 9 Apr 2015 12:01:42 +0000 (UTC)

Ralph, good to hear that you were able to stream with DVB-T.

BTW, Clayton used DVB-T to stream video for several miles and he put it on his blog: http://www.irrational.net/2014/03/02/digital-atv/

You may find it useful.


On Thursday, April 9, 2015 12:46 PM, "Ralph A. Schmid, dk5ras" <address@hidden> wrote:

Short update: I was able to transmit my own stream now, audio stuttered a bit, but for sure I will find out how to fix this. It was a short iPhone video of a snake in front of our office (we do not have so much snakes here in Germany), and it was fun seeing this transmitted via DVB-T :)
From: Bogdan Diaconescu [mailto:address@hidden
Sent: Wednesday, April 8, 2015 5:13 PM
To: Ralph A. Schmid, dk5ras; 'Ron Economos'; address@hidden
Subject: Re: [Discuss-gnuradio] DVB-T/T2
Hi Ralf,
having Us when moving the mouse does not looks good. Can you show a picture taken with htop (on Linux).
the coding is a setting of the transmitter and receiver and it just need to be the same on both. It does impact the maximum bitrate of the stream as in the table.
Look into the 4.5.4 and 4.5.5 chapters. It says that reference information is sent at "boosted" power level with imaginary equal zero. This is what you see in the two dots on left and right.
On Wednesday, April 8, 2015 5:34 PM, "Ralph A. Schmid, dk5ras" <address@hidden> wrote:
The Us are when I do something else with the machine. They do not show when I keep my fingers off the mouse, so no reason to worry, it runs for ages without a single U when the machine is kept alone.

I already found out about the rate. The coding also needs to be reflected by the transport stream, or just regarding the bitrate? I did not find a setting for that, but I will look deeper into it during the next days, when I find some time. My first test trying to set identical settings like from the working test stream brought just a black picture.
Another question...when looking into the constellation, what are the two dot clouds on the X/I-axis, outside the expected 4*4 cloud matrix? Some embedded BPSK? I could not find this in the DVB-T specs at first glance...
From: Bogdan Diaconescu [mailto:address@hidden]
Sent: Wednesday, April 8, 2015 2:57 PM
To: Ralph A. Schmid, dk5ras; 'Ron Economos'; address@hidden
Subject: Re: [Discuss-gnuradio] DVB-T/T2
Hi Ralph,
DVB-T.png shows some u's on the command line which means the whole flowgraph do not provide data to USRP at the right speed. It basically mean the computer cannot cope with the required processing requirement.
As for the video parameters, in the DVB-T specs (http://www.etsi.org/deliver/etsi_en/300700_300799/300744/01.06.01_60/en_300744v010601p.pdf) you will find Table 17 where the rates are presented. FYI, the settings you have used are 8Mhz bandwidth, QAM-16 constellation, coding 1/2, guard interval 1/32. The video should be constant bit rate but it is not a hard requirement (see below).
If you just broadcast video from a file and not plan to use a live streaming from camera, the rate should not matter too much. The video is sent at the rate of the DVB-T according to it's parameters and with RTL2832 receiver it is buffered and played at the correct speed (at least for short files like test.ts).
On Wednesday, April 8, 2015 11:55 AM, "Ralph A. Schmid, dk5ras" <address@hidden> wrote:
Yep, this would be quite useful!

Bogdan, as you are here, too - I don't know very much about all the crazy video file stuff, but maybe you can give me some basic parameters I need to comply with for a transport stream, to be able to transmit it with your package?! I need to use Windows for the conversion, as my Linux installation is only on a virtual machine, with limited space and power. A capable looking Windows program is available, but there are so many options I have no clue about :(
I modified your flow graph according to Rons hints, and now I have a stable and reliable DVB-T transmission path with your package. See http://dk5ras.dyndns.org/tmp/DVB/ with a screenshot. I am using the Ettus B210, and for reception a second PC with DVB-T stick, or a DVB-x tester that does them all, DVB-C/S/S2/T/T2.
You and Ron really did a great job with coding those DVB-x packages!
From: address@hidden [mailto:address@hidden] On Behalf Of Bogdan Diaconescu
Sent: Wednesday, April 8, 2015 8:01 AM
To: Ron Economos; address@hidden
Subject: Re: [Discuss-gnuradio] DVB-T/T2
Ok, it would be useful to have receivers too like for the DVB-T.
On Tuesday, April 7, 2015 11:23 PM, Ron Economos <address@hidden> wrote:
Only transmitter implementations for now. They are here:



The DVB-T2 implementation supports T2-Lite, tone reservation PAPR reduction and MISO processing.

On 04/07/2015 06:38 AM, Bogdan Diaconescu wrote:
Hi Ron,
I have not followed the development of DVB-T2/S2 lately. Are there receiver implementations for the T2/S2 or just transmitters?
On Tuesday, April 7, 2015 1:32 PM, "Ralph A. Schmid, dk5ras" <address@hidden> wrote:
Great to hear that you work finds its way into the official thing!
At the moment, as the RF stuff works, I am trying to learn about all this crazy video file stuff, for being able to create transport streams with my own content. Up to now I am still testing with the cartoon .ts :) Still my laptop (with DVBViewer software) will not decode the audio, while the DVB tester decodes audio just fine.
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