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 <[email protected]> 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 <[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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