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

[Vanush Vaswani]

Hey guys, why does digital video need its own standard?

On Thu, Apr 9, 2015 at 7:45 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 :)
>
>
>
> Ralph.
>
>
>
> 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.
>
>
>
> Bogdan
>
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> On Wednesday, April 8, 2015 5:34 PM, "Ralph A. Schmid, dk5ras"
> <address@hidden> wrote:
>
>
>
> Hi,
>
>
>
> 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...
>
>
>
> Ralph.
>
>
>
>
>
> 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).
>
>
>
> Bogdan
>
>
>
>
>
> 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!
>
>
>
> Ralph.
>
>
>
> 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.
>
>
>
> Bogdan
>
>
>
>
>
> On Tuesday, April 7, 2015 11:23 PM, Ron Economos <address@hidden> wrote:
>
>
>
> Only transmitter implementations for now. They are here:
>
> https://github.com/drmpeg/gr-dvbs2
>
> https://github.com/drmpeg/gr-dvbt2
>
> The DVB-T2 implementation supports T2-Lite, tone reservation PAPR reduction
> and MISO processing.
>
> Ron
>
> 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?
>
>
>
> Thanks,
>
> Bogdan
>
>
>
>
>
> 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.
>
>
>
> Ralph.
>
>
>
>
>
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