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 <[email protected]> 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 <[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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