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

Sun Jul 5 10:04:41 EDT 2015

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
>>>>>>>
>>>>>>>
>>>>>
>>>
>>> _______________________________________________
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>>>
>>>
>>
>
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