DATV-Express Project - January update report

[G4GUO]

I may add an option to allow lower frame rates than standard definition for things like
reduced bandwidth TV where quality is probably more important than refresh rate.

I means adding yet another configuration dialog.

- Charles

[g0mjw]

I like the call - PA 1KW should give a strong signal.

I would quite like to be able to disable sound on very low symbol rate transmissions.

Mike

[ON1AVO]

Hi Charles,

All installed on another laptop (i5 5300U) OS W8.1 and it works after a little tweaking.
Observations:
- internal webcam: TX queue gets full and demodulated video is distorted

Datv Express Webcam.jpg (189.58 KiB) Viewed 8461 times

- Restart necessary on changes to take effect although the GUI shows already the changed parameters, normal behavior?

I'll give it another try on the first laptop (W7pro) and see if I still get the previous mentioned errors.

Freddy

[G4GUO]

Hi Freddy,

I will try the settings you have used and see whether I get the same results.

No I don't get the Tx queue filling. I suspect there was something wrong with the Express card (needed a reset).

After you make a change you need to
File->Save Configuration
then
File->Restart

- Charles

[ON1AVO]

Charles,

This morning I noticed another problem trying to access our local repeater ON0ATV.
When I change the TX frequency to 2340 MHz I get this weird TX freq. 2147483647 Hz.
I changed in both datvexpress.txt & .bak the weird freq. to 2340 MHz but no change still this weird TX freq.
Uninstall and reinstall Express DVB-S didn't help to solve this problem.
When I use a 23cm freq. (1281 MHz) it's alright but no luck with any 13cm freq. always TX freq. 2147483647 Hz.
I didn't encounter this when using DATVExpress Server.

Datv Express 2340MHz.jpg (239.96 KiB) Viewed 8335 times

Freddy

[G4GUO]

Thanks Freddy,
I have found the bug, it was a string conversion error.
I will post a fixed version later this weekend I am making some further changes today.
Here is the temporary fix

https://www.dropbox.com/s/bm1cvegsncxre ... x.zip?dl=0

- Charles

[g0mjw]

Hi Charles,

I have found after a while the express board needs a power cycle. Its a bit difficult to reproduce but the effect is a transmission but no decodable TS. Its like its sending nulls maybe?

Mike

[G4GUO]

Possibly, I think it is more likely that the DTS/PTS/PCR clocks have gone wrong.
It is a bit difficult for me to soak test the software and carry on developing it at the
same time as I only have one Windows computer at the moment located in a warm room.

I will try setting it up on the unheated Workshop computer and leave it running for a few hours.

- Charles

[M0DTS]

Hi all,

Just installed the new Express Software on my PIPO and I'm happy to say it works well!

Tested 4Ms at 7/8 FEC (so 5.5Mb/s Video content) with both Mpeg2 and Mpeg4 without any problem, although cpu was in low 90% when using h264 it was decoding fine on the receiver and no queue issues. The latency also remains very good.
Tested with a Logitech webcam and Easycap usb AV capture dongle, both work OK as video sources.

I also tested using vmix as the capture source and this also worked fine including an overlay too.

It makes a very simple setup for Reduced Bandwidth and regular DATV in one box with a small pc.. very cool!

Rob
M0DTS

[G4GUO]

Hi Rob,
I must admit my Pipo is languishing in it's box. I am quite surprised it works that well.

I have been trying to add a simple text overlay but have not got very far with it.
There seem to be two ways, either use the FFmpeg filter manager or what I am doing,
use Windows Bitmaps to format the text then overlaying the bitmap on the YUV420P
frame that goes into the Codec.

- Charles