[Hackrf-dev] DVB-T and DVB-T2

Sun Jul 5 10:17:08 EDT 2015

Thanks for your help guys.

Yeah same here Simon, I have been playing with frame rates and noticed my
TV supports up to 50ish then display nothing!

I'd like to play with DVB-T2 next once I've got the hang of this.
On 5 Jul 2015 15:08, "Simon Kennedy" <simon at thekennedys.info> wrote:

> Cool, I'll delete the email I was about to send! I had forgotten that you
> were trying to tx DVB-T. However, I remember that when I was playing with
> DVB-T I was able to use framerates from 25 to 60, but maybe it depends on
> the TV your are using.
>
> I used an RTL-SDR dongle for receiving and found that avconv worked
> perfectly but using ffmpeg I could only get a pixellated image, go figure!
>
> Simon.
>
> On 5 July 2015 at 15:04, Craig Barber <radiocraig28 at gmail.com> wrote:
>
>> Bingo... I had to change the video frame rate from 60 down to 25 which I
>> found is apparently what is broadcasted in the UK for Digital TV... and now
>> I have video!
>>
>> On Sun, Jul 5, 2015 at 2:54 PM, Craig Barber <radiocraig28 at gmail.com>
>> wrote:
>>
>>> Hi Simon,
>>>
>>> The mpeg2 TS plays fine in mplayer and VLC and I get video and sound,
>>> but on my test bench TV I only hear the audio. I've tried a couple of
>>> different bitrates for the video too but no luck.
>>>
>>> I've edited dvbt-hackrf_tx_sk.py to use channel_mhz = 8 as I understand
>>> that is what is normally used in the UK for UHF DVB-T. Any other option
>>> other than that and I don't seem to see any signal at all on the test TV.
>>>
>>> Craig
>>>
>>> On Sun, Jul 5, 2015 at 2:51 PM, Simon Kennedy <simon at thekennedys.info>
>>> wrote:
>>>
>>>> HI Craig,
>>>>
>>>> just seen your emails. Try using mplayer to play the ts from the fifo
>>>> file. This will enable you to double check that the first part of the
>>>> process is ok, ie. the creation of the mpeg2 ts.
>>>>
>>>> Where have you put channel_mhz = 8?
>>>>
>>>> Earlier today I had someone else email me to tell me that they have had
>>>> success with the commands and program I put on my blog post so I know it
>>>> does work for someone else!
>>>>
>>>> Regards
>>>> Simon.
>>>>
>>>> On 5 July 2015 at 14:41, Craig Barber <radiocraig28 at gmail.com> wrote:
>>>>
>>>>> Thankyou, I just found it (https://en.wikipedia.org/wiki/DVB-T), I
>>>>> now have stable sound (getting there!) but no video oddly! The command I'm
>>>>> using to create the TS before broadcast is as follows:
>>>>>
>>>>> avconv -f alsa -i hw:0,0 -f video4linux2 -s 640x480 -i /dev/video0 -vf
>>>>> drawtext=fontfile=/usr/share/fonts/truetype/freefont/FreeMonoBold.ttf:text="TEST
>>>>> ":x=440:y=420:fontsize=48:fontcolor=white at 0.6:box=1:boxcolor=black at 0.4
>>>>> -vcodec mpeg2video -r 60 -b 2500000 -acodec mp2 -ar 48000 -ab 48000 -ac 2
>>>>> -muxrate 4976000 -mpegts_transport_stream_id 1025 -mpegts_service_id 1
>>>>> -mpegts_pmt_start_pid 4096 -mpegts_start_pid 400 -f mpegts -y test3
>>>>>
>>>>> I'm then using QPK, with 1/2 code rate and 1/4 guard interval which
>>>>> expects a bitrate of 4.976mbps so should be correct?
>>>>>
>>>>> On Sun, Jul 5, 2015 at 2:16 PM, n0p [Luis Bernal] <lbernal at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> The modulator bitrate depends of it's parameters, there's a nice
>>>>>> table with the formula but i can't find it now since I'm on mobile
>>>>>> El 5/7/2015 14:48, "Craig Barber" <radiocraig28 at gmail.com> escribió:
>>>>>>
>>>>>>> Thanks for the fast response n0p but I cannot find that parameter?
>>>>>>>
>>>>>>> On Sun, Jul 5, 2015 at 1:34 PM, n0p [Luis Bernal] <lbernal at gmail.com
>>>>>>> > wrote:
>>>>>>>
>>>>>>>> The ts mux bitrate has to match the modulator's
>>>>>>>> Avconv parameter -muxrate
>>>>>>>> El 5/7/2015 14:11, "Craig Barber" <radiocraig28 at gmail.com>
>>>>>>>> escribió:
>>>>>>>>
>>>>>>>>> The good news is I got it working, sort of, using channel_mhz = 8
>>>>>>>>> - however the picture and audio judders really badly, and basically plays
>>>>>>>>> back really slow! I don't have a stream of UUUUUUUUUUU appearing in my
>>>>>>>>> console window, so can't be buffer underruns, any ideas Simon?
>>>>>>>>>
>>>>>>>>> On Sun, Jul 5, 2015 at 12:30 PM, Craig Barber <
>>>>>>>>> radiocraig28 at gmail.com> wrote:
>>>>>>>>>
>>>>>>>>>> Hi Simon,
>>>>>>>>>>
>>>>>>>>>> I've tried your script today with my test TV but see no signal
>>>>>>>>>> whatsoever on the TV although the hackrf is definitely transmitting. I've
>>>>>>>>>> also tried with a pre-recoded mpeg2 file from avconv but no luck.
>>>>>>>>>>
>>>>>>>>>> Any suggestions?
>>>>>>>>>>
>>>>>>>>>> Craig
>>>>>>>>>>
>>>>>>>>>> On Tue, Jun 30, 2015 at 10:57 PM, Simon Kennedy <
>>>>>>>>>> simon at thekennedys.info> wrote:
>>>>>>>>>>
>>>>>>>>>>> I feel slightly embarrassed as I subscribed to this list using
>>>>>>>>>>> an email address that is redirected to my main email, so consequently
>>>>>>>>>>> replies sent from my main email address were not coming from the correct
>>>>>>>>>>> address. Hence, none of the replies I posted have been seen on the list.
>>>>>>>>>>> Oops!
>>>>>>>>>>>
>>>>>>>>>>> Here is my reply about this thread:
>>>>>>>>>>>
>>>>>>>>>>> Hi Craig,
>>>>>>>>>>>
>>>>>>>>>>> Check out Clayton's web page (who created the sdr-examples you
>>>>>>>>>>> refer to) here
>>>>>>>>>>> <http://www.irrational.net/2014/03/02/digital-atv/>
>>>>>>>>>>>
>>>>>>>>>>> I amended his BladeRF script and I have put my HackRF version
>>>>>>>>>>> here
>>>>>>>>>>> <https://www.dropbox.com/s/bdnzoa0kn01dfav/dvbt-hackrf_tx_sk.py?dl=0> for
>>>>>>>>>>> download
>>>>>>>>>>> My version transmits DVB-T on the lowest Freeview channel in the
>>>>>>>>>>> UK at 474MHz (obviously only while using a dummy load). I successfully
>>>>>>>>>>> received the transmission of my webcam image this way using an RTL-SDR
>>>>>>>>>>> dongle.
>>>>>>>>>>>
>>>>>>>>>>> The command I used was very heavily influenced (ok, basically
>>>>>>>>>>> copied) from Clayton's examples:
>>>>>>>>>>> avconv -f alsa -i hw:0,0 -f video4linux2 -s 640x480 -i
>>>>>>>>>>> /dev/video0 -vf
>>>>>>>>>>> drawtext=fontfile=/usr/share/fonts/truetype/freefont/FreeMonoBold.ttf:text="TEST
>>>>>>>>>>> ":x=440:y=420:fontsize=48:fontcolor=white at 0.6
>>>>>>>>>>> :box=1:boxcolor=black at 0.4 -vcodec mpeg2video -r 60 -b 2000000
>>>>>>>>>>> -acodec mp2 -ar 48000 -ab 48000 -ac 2 -mpegts_transport_stream_id 1025
>>>>>>>>>>> -mpegts_service_id 1 -mpegts_pmt_start_pid 4096 -mpegts_start_pid 400 -f
>>>>>>>>>>> mpegts -y in.fifo
>>>>>>>>>>>
>>>>>>>>>>> I used a standard web cam to capture the image, sent the output
>>>>>>>>>>> to a fifo file (in.fifo) and consumed the output through the python program
>>>>>>>>>>> with the command:
>>>>>>>>>>> ./dvbt_hackrf_tx_sk.py in.fifo
>>>>>>>>>>>
>>>>>>>>>>> The fifo file can be created using the command mkfifo in.fifo
>>>>>>>>>>>
>>>>>>>>>>> Run the avconv command and the python program in the same
>>>>>>>>>>> directory as you created the fifo file in.
>>>>>>>>>>>
>>>>>>>>>>> I have also transmitted DVB-S which I have documented on my blog
>>>>>>>>>>> here
>>>>>>>>>>> <http://photohamrad.blogspot.co.uk/2015/06/transmitting-video-with-hackrf-blue.html>
>>>>>>>>>>>
>>>>>>>>>>> Simon.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On 30 June 2015 at 17:35, Simon Kennedy <simon at thekennedys.info>
>>>>>>>>>>> wrote:
>>>>>>>>>>>
>>>>>>>>>>>> Can you tell us the command you used to get this error please.
>>>>>>>>>>>> I remember that I got a smilar error but cannot look up how I
>>>>>>>>>>>> solved it until I get home in a couple of hours.
>>>>>>>>>>>> The key point is that the program is trying to open a UDP port
>>>>>>>>>>>> to receive the data and error relates to the asignment of the argument you
>>>>>>>>>>>> supply to the program to the variable 'port' in the program.
>>>>>>>>>>>>
>>>>>>>>>>>> Simon.
>>>>>>>>>>>>
>>>>>>>>>>>> On 30 June 2015 at 16:49, Craig Barber <radiocraig28 at gmail.com>
>>>>>>>>>>>> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>>> Here's the error I get:
>>>>>>>>>>>>>
>>>>>>>>>>>>> Traceback (most recent call last):
>>>>>>>>>>>>>   File "./dvbt-hackrf.py", line 123, in <module>
>>>>>>>>>>>>>     main(sys.argv[1:])
>>>>>>>>>>>>>   File "./dvbt-hackrf.py", line 31, in main
>>>>>>>>>>>>>     port    = int(args[0])
>>>>>>>>>>>>> ValueError: invalid literal for int() with base 10: 'testdvbt'
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> _______________________________________________
>>>>>>>>>>> HackRF-dev mailing list
>>>>>>>>>>> HackRF-dev at greatscottgadgets.com
>>>>>>>>>>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> _______________________________________________
>>>>>>>>> HackRF-dev mailing list
>>>>>>>>> HackRF-dev at greatscottgadgets.com
>>>>>>>>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>>>>>>>>
>>>>>>>>>
>>>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> HackRF-dev mailing list
>>>>> HackRF-dev at greatscottgadgets.com
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>>>>>
>>>>>
>>>>
>>>
>>
>
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