|
| From: | Mir Muhammad Lodro |
| Subject: | Re: [Discuss-gnuradio] gr-modtool |
| Date: | Mon, 11 Feb 2019 13:05:07 +0000 |
Thanks for your reply. I can see the gr_modtool in the said directory. However, I can't start gnuradio using
~/prefix/default/bin/gnuradio-companion
When I do this it says:
address@hidden:~/prefix/default/bin$ gnuradio-companion
Command 'gnuradio-companion' not found, but can be installed with:
sudo apt install gnuradio
Apparently, there is no other gnuradio installation. How to know that I have multiple gnuradio copies installed.
Thanks
Mir
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Today's Topics:
1. Re: bit stuffing DVB-S TX example ? (Alban Meffre)
2. Re: bit stuffing DVB-S TX example ? (Ron Economos)
3. Re: bit stuffing DVB-S TX example ? (Ron Economos)
4. Re: gr-modtool (Cinaed Simson)
----------------------------------------------------------------------
Message: 1
Date: Fri, 8 Feb 2019 18:59:12 +0100
From: Alban Meffre <address@hidden>
To: "Raydel Abreu (CM2ESP)" <address@hidden>
Cc: Ron Economos <address@hidden>, discuss-gnuradio
<address@hidden>
Subject: Re: [Discuss-gnuradio] bit stuffing DVB-S TX example ?
Message-ID:
<address@hidden>
Content-Type: text/plain; charset="utf-8"
hi thanks for your answers
my symbol rate is 300 ksps
using this calculator
http://www.satbroadcasts.com/DVB-S_Bitrate_and_Bandwidth_Calculator.html
and these settings : QPSK rate 1/2 FEC frame 64800
i get 276.5 kbps of TS bitrate
here are my settings for ffmpeg :
*ffmpeg -re -f lavfi -i testsrc=s=640x480:r=25:n=1 -vf
"drawtext=text=%{localtime}:x=(w-tw)/2:y=h-th-37:fontsize=20:fontcolor=yellow:borderw=2:bordercolor=black"
-pix_fmt yuv420p -an -g 25 -b:v 228k -c:v libx264 -tune zerolatency
-maxrate 228k -bufsize 230k -nal-hrd cbr -f mpegts
udp://127.0.0.1:1234?pkt_size=188 <http://127.0.0.1:1234?pkt_size=188>*
this generates a test pattern very close to 275 kbps
as i'm very close to the DVB-S net bitrate i get a near constant output
power (with some small gaps) and SDRAngel is quite happy
i will play with the -muxrate option to see if this keeps tightly the
bitrate at maximum limit
best regards
Bob
Le ven. 8 f?vr. 2019 ? 13:22, Raydel Abreu (CM2ESP) <address@hidden> a
?crit :
> Hi Ron
>
> That formula it's very useful! Thanks. I have a silly question (sorry for
> it). If I understand correctly 8000000 is the symbol rate and 12901961 is
> the TS rate? Correct?
>
> The multiply by 2 is because Tx signal is QPSK? If that's so then it will
> be 1 for BPSK, 3 for 8PSK and so on.... Am I right?
>
> Thanks!
>
> Raydel
>
>
>
>
> El jue., 7 de feb. de 2019 7:26 PM, Ron Economos <address@hidden>
> escribi?:
>
>> First, you have to match the TS rate to the symbol rate. The equation is:
>>
>> Symbol rate * 2 * 188/204 * code rate
>>
>> For the example flow graph:
>>
>> 8000000 * 2 * 188/204 * 7/8 = 12.901961 Mbps
>>
>> Second, you need to constrain the video bitrate to fit into the selected
>> TS bitrate. With ffmpeg, something like this:
>>
>> ffmpeg -i test.mp4 -c:v libx264 -b:v 10M -minrate 11M -maxrate 11M
>> -bufsize 8M -c:a copy -muxrate 12901961 test.ts
>>
>> For SD video, a smaller bufsize like 2M should be used.
>>
>> Ron
>> On 2/7/19 15:15, Alban Meffre wrote:
>>
>> Hi All
>> did some transmission test in DVB-S tonight
>> TX : ffmpeg + gnuradio + pluto SDR
>> RX : RTLSDR + sdrangel
>> it works but there are some gaps in the received signal because the TS
>> stream bitrate is slightly less to the maximum usable bitrate
>>
>> is it possible to add some bit stuffing at DVB-S modulator side to make
>> to output power constant ?
>>
>> Bob
>>
>> --
>> Alban MEFFRE F4GSW
>>
>>
>>
>> _______________________________________________
>> Discuss-gnuradio mailing address@hidden://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>
>> _______________________________________________
>> Discuss-gnuradio mailing list
>> address@hidden
>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
--
Alban MEFFRE F4GSW
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Message: 2
Date: Fri, 8 Feb 2019 12:25:21 -0800
From: Ron Economos <address@hidden>
To: discuss-gnuradio <address@hidden>
Subject: Re: [Discuss-gnuradio] bit stuffing DVB-S TX example ?
Message-ID: <address@hidden>
Content-Type: text/plain; charset="utf-8"; Format="flowed"
Raydel,
??? You are correct on both points. QPSK (the only allowed
constellation in DVB-S) is 2 bits per symbol.
Ron
On 2/8/19 04:20, Raydel Abreu (CM2ESP) wrote:
> Hi Ron
>
> That formula it's very useful! Thanks. I have a silly question (sorry
> for it). If I understand correctly 8000000 is the symbol rate and
> 12901961 is the TS rate? Correct?
>
> The multiply by 2 is because Tx signal is QPSK? If that's so then it
> will be 1 for BPSK, 3 for 8PSK and so on.... Am I right?
>
> Thanks!
>
> Raydel
>
>
>
>
> El jue., 7 de feb. de 2019 7:26 PM, Ron Economos <address@hidden
> <mailto:address@hidden>> escribi?:
>
> First, you have to match the TS rate to the symbol rate. The
> equation is:
>
> Symbol rate * 2 * 188/204 * code rate
>
> For the example flow graph:
>
> 8000000 * 2 * 188/204 * 7/8 = 12.901961 Mbps
>
> Second, you need to constrain the video bitrate to fit into the
> selected TS bitrate. With ffmpeg, something like this:
>
> ffmpeg -i test.mp4 -c:v libx264 -b:v 10M -minrate 11M -maxrate 11M
> -bufsize 8M -c:a copy -muxrate? 12901961 test.ts
>
> For SD video, a smaller bufsize like 2M should be used.
>
> Ron
>
> On 2/7/19 15:15, Alban Meffre wrote:
>> Hi All
>> did some transmission test in DVB-S tonight
>> TX : ffmpeg + gnuradio + pluto SDR
>> RX : RTLSDR + sdrangel
>> it works but there are some gaps in the received signal because
>> the TS stream bitrate is slightly less to the maximum usable bitrate
>>
>> is it possible to add some bit stuffing at DVB-S modulator side
>> to make to output power constant ?
>>
>> Bob
>>
>> --
>> Alban MEFFRE F4GSW
>>
>>
>>
>> _______________________________________________
>> Discuss-gnuradio mailing list
>> address@hidden <mailto:address@hidden>
>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden <mailto:address@hidden>
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
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------------------------------
Message: 3
Date: Fri, 8 Feb 2019 12:40:42 -0800
From: Ron Economos <address@hidden>
To: discuss-gnuradio <address@hidden>
Subject: Re: [Discuss-gnuradio] bit stuffing DVB-S TX example ?
Message-ID: <address@hidden>
Content-Type: text/plain; charset="utf-8"; Format="flowed"
Alban,
??? It's absolutely critical that you use the -muxrate option in
ffmpeg. If you don't, you get a variable rate Transport Stream, which is
guaranteed to cause problems.
Also, I would specify the muxrate to 1 bps of accuracy. ffmpeg supports
it. So for 300 kSyms/s, it would be 276471.
You don't really need the -nal-hrd cbr parameter. The video bitrate can
be variable, but the peak video? bitrate (combined with the audio
bitrate) can't exceed the TS rate.
BTW, the RF power output is not changing. It's just the player not being
able to decode the bitstream properly.
Ron
On 2/8/19 09:59, Alban Meffre wrote:
> hi thanks for your answers
>
> my symbol rate is 300 ksps
> using this calculator
> http://www.satbroadcasts.com/DVB-S_Bitrate_and_Bandwidth_Calculator.html
> and these settings : QPSK rate 1/2 FEC frame 64800
> i get 276.5 kbps of TS bitrate
>
> here are my settings for ffmpeg :
> *ffmpeg -re -f lavfi -i testsrc=s=640x480:r=25:n=1 -vf
> "drawtext=text=%{localtime}:x=(w-tw)/2:y=h-th-37:fontsize=20:fontcolor=yellow:borderw=2:bordercolor=black"
> -pix_fmt yuv420p -an -g 25? -b:v 228k -c:v libx264 -tune zerolatency
> -maxrate 228k -bufsize 230k -nal-hrd cbr -f mpegts
> udp://127.0.0.1:1234?pkt_size=188 <http://127.0.0.1:1234?pkt_size=188>*
>
> this generates a test pattern very close to 275 kbps
>
> as i'm very close to the DVB-S net bitrate i get a near constant
> output power (with some small gaps) and SDRAngel is quite happy
>
> i will play with the -muxrate option to see if this keeps tightly the
> bitrate at maximum limit
>
> best regards
> Bob
>
>
>
> Le?ven. 8 f?vr. 2019 ??13:22, Raydel Abreu (CM2ESP) <address@hidden
> <mailto:address@hidden>> a ?crit?:
>
> Hi Ron
>
> That formula it's very useful! Thanks. I have a silly question
> (sorry for it). If I understand correctly 8000000 is the symbol
> rate and 12901961 is the TS rate? Correct?
>
> The multiply by 2 is because Tx signal is QPSK? If that's so then
> it will be 1 for BPSK, 3 for 8PSK and so on.... Am I right?
>
> Thanks!
>
> Raydel
>
>
>
>
> El jue., 7 de feb. de 2019 7:26 PM, Ron Economos <address@hidden
> <mailto:address@hidden>> escribi?:
>
> First, you have to match the TS rate to the symbol rate. The
> equation is:
>
> Symbol rate * 2 * 188/204 * code rate
>
> For the example flow graph:
>
> 8000000 * 2 * 188/204 * 7/8 = 12.901961 Mbps
>
> Second, you need to constrain the video bitrate to fit into
> the selected TS bitrate. With ffmpeg, something like this:
>
> ffmpeg -i test.mp4 -c:v libx264 -b:v 10M -minrate 11M -maxrate
> 11M -bufsize 8M -c:a copy -muxrate 12901961 test.ts
>
> For SD video, a smaller bufsize like 2M should be used.
>
> Ron
>
> On 2/7/19 15:15, Alban Meffre wrote:
>> Hi All
>> did some transmission test in DVB-S tonight
>> TX : ffmpeg + gnuradio + pluto SDR
>> RX : RTLSDR + sdrangel
>> it works but there are some gaps in the received signal
>> because the TS stream bitrate is slightly less to the maximum
>> usable bitrate
>>
>> is it possible to add some bit stuffing at DVB-S modulator
>> side to make to output power constant ?
>>
>> Bob
>>
>> --
>> Alban MEFFRE F4GSW
>>
>>
>>
>> _______________________________________________
>> Discuss-gnuradio mailing list
>> address@hidden <mailto:address@hidden>
>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden <mailto:address@hidden>
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden <mailto:address@hidden>
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
>
>
> --
> Alban MEFFRE F4GSW
>
>
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------------------------------
Message: 4
Date: Fri, 8 Feb 2019 12:43:12 -0800
From: Cinaed Simson <address@hidden>
To: address@hidden
Subject: Re: [Discuss-gnuradio] gr-modtool
Message-ID: <address@hidden>
Content-Type: text/plain; charset=utf-8
On 2/8/19 4:45 AM, Mir Muhammad Lodro wrote:
> Hi,
> I am trying to create OOT using gr_modtool. It responds with the
> following output:
>
> address@hidden:~/prefix/default$ gr_modtool newmod howto
> Command 'gr_modtool' not found, but can be installed with:
>
> sudo apt install gnuradio
>
> I have installed fresh copy of the GNU Radio using PyBombs.
Make sure there's only 1 copy of gnuradio installed on you system.
It should be located in
~/prefix/default/bin/gr_modtool
Can you start
~/prefix/default/bin/gnuradio-companion
-- Cinaed
>
> Thanks
> Mir
>
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
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