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

Sun Jul 5 09:51:03 EDT 2015

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
>>>>>
>>>>>
>>>
>
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