Command to use ffplay on test_output.ts file

git-artes / gr-isdbt

DTV ISDB-T in GNURadio

http://iie.fing.edu.uy/investigacion/grupos/artes/gr-isdbt/

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Command to use ffplay on test_output.ts file #25

Closed ergwd-pcieerd closed 6 years ago

ergwd-pcieerd commented 6 years ago

Hi, I just need to know what actual command to use in playing test_output.ts file with ffplay? I never used ffmpeg and ffplay before and directly using ffplay test_output.ts doesn't show anything. Do I need to convert the file with ffmpeg to a .mp4 format, then use ffplay? Just got to ask as this might actually be a one liner you guys readily know...

Thanks a lot for attending to my newbie questions.

Cheers, Daryl

git-artes commented 6 years ago

Hi, What's the size of the resulting test_output.ts? Because if it is 0 byte, it means the RS decoder is considering the stream beyond correction, typically meaning (if your constellation is "nice") that you are setting the parameters wrong (e..g time interleaver depth). best

ergwd-pcieerd commented 6 years ago

I see... I got ffplay running by using one of your demo .dat files (569MHz_recording.dat). It's constellation and video playback is shown in the attached image. So for it to be accepted by the RS decoder, I guess my constellation will have to like something like it right?

Will check test_out.ts on my own experiment. Will get back at this.

ergwd-pcieerd commented 6 years ago

Going back to my own experiment, and checking test_out.ts, it is 0 byte indeed. The constellation was also nothing like in above (image below).

I'm attaching my flowgraph below, perhaps you can see which parameter I got wrong? I'm using ADALM-Pluto SDR for this. I really appreciate you helping out on this. rx_demo grc

ergwd-pcieerd commented 6 years ago

Following up:

Is this the expected form of the obtaining parameters flowgraph?

I now understand the instructions better...but, I will need to find the parameters that can give this kind of form.

Thanks, Daryl

git-artes commented 6 years ago

Exactly, you'll have to first test which are the mode and the guard interval (when you obtain a graph like in the last image you attached), and then (when the constellation is "nice") you'll have to obtain the rest of the parameters by enabling "print parameters" in the tmcc decoder block. best

git-artes commented 6 years ago

I forgot to mention that I've never used a ADALM-Pluto SDR, so I'm not sure if it may be problematic. With the USRP you have to be extra careful with the supported sampling rates and gain.

ergwd-pcieerd commented 6 years ago

OK, thanks for confirming that...I will find those parameters - I'll get back at this on my next free time. You can close this issue now sir. as ffplay turned out fine when fed with correct isdbt data.