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 <[email protected]> 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 <[email protected]> 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:[email protected]:box=1:[email protected] >> -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] <[email protected]> >> 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" <[email protected]> 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] <[email protected]> >>>> wrote: >>>> >>>>> The ts mux bitrate has to match the modulator's >>>>> Avconv parameter -muxrate >>>>> El 5/7/2015 14:11, "Craig Barber" <[email protected]> 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 <[email protected] >>>>>> > 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 < >>>>>>> [email protected]> 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:[email protected] >>>>>>>> :box=1:[email protected] -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 <[email protected]> >>>>>>>> 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 <[email protected]> >>>>>>>>> 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 >>>>>>>> [email protected] >>>>>>>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev >>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> HackRF-dev mailing list >>>>>> [email protected] >>>>>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev >>>>>> >>>>>> >>>> >> >> _______________________________________________ >> HackRF-dev mailing list >> [email protected] >> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev >> >> >
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