Want to resurrect your D/D2 MAC kit?

[Captain Jack]

Strangely, when I put the decoder into service mode, it doesn't lose the lock and stays on. Wonder if there's interference or something odd going on with the converted file that causes it to lose lock every minute. Or receiver... or a quirk with the decoder itself.

 

[fsphil]

Other things took priority for a bit there, but better late than never here's the latest D-MAC encoder and updated script with a more correct pre-emphasis filter: GitHub - fsphil/television.py: Experimental analogue video encoders

On my BSB receiver this locks on in pass-through mode, but glitches every three seconds. In normal mode it just displays a black screen and message saying there's no signal. I'm not sure why that's not working - there's still a lot of the digital data that I'm just padding with random bits so it might need everything to be correct first before it even shows an image. Annoying

 

[Analoguesat]

Brilliant stuff guys - I love reading about this sort of tinkering from our members

 

[Captain Jack]

Thanks Phil - will give it a go!

How are your IC programming skills? Could be converted to a real time hardware encoder. Sadly, my extent of VHDL and assembler knowledge only allows me to operate a 7 segment display... [emoji53] And that was many years ago!

 

[Captain Jack]

Brilliant stuff guys - I love reading about this sort of tinkering from our members

Feel free to give it a go! World be a shame not to with your nick

 

[Captain Jack]

Tried the latest version of converted but still losing lock every second - no idea why. Could be the receiver but just seems weird that it locks and then loses lock. Unless it's in service mode, in which case the lock is permanent.

No such issue from the generator so either the receiver or HackRF.. or we're just not quite there yet

 

[Captain Jack]

Hi Phil, would you mind uploading some PAL encoders? Want to see what I can get there.

 

[fsphil]

I've pushed the pal encoder, and an example grc script for transmitting AM and FM. I don't have the old Sky receiver handy so can't test it with FM for satellite at the moment.
It is extremely slow. Especially the first time you run it as it needs to generate lookup tables. But even after that, on my laptop it barely gets 0.1 fps.

The C version is much faster but not ready yet

 

[Captain Jack]

Thanks Phil. Gave it a go with my TV and it works - sorta. The script seems to be stuck on muxing audio with the video

frame=  606 fps=0.4 q=-0.0 size= 1062507kB time=00:00:24.24 bitrate=359078.4kbit
frame=  607 fps=0.4 q=-0.0 size= 1064261kB time=00:00:24.28 bitrate=359078.4kbit
frame=  608 fps=0.4 q=-0.0 size= 1066014kB time=00:00:24.32 bitrate=359078.4kbit
frame=  608 fps=0.4 q=-0.0 size= 1066014kB time=00:00:24.32 bitrate=359078.4kbit
frame=  608 fps=0.4 q=-0.0 Lsize= 1066014kB time=00:00:24.32 bitrate=359078.4kbits/s   
video:1066014kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.000000%

Also, the flowgraph outputs to hackrf through osmocom sink twice - one for audio, the other for video(?). But when I run it, it say it cannot open hackrf device as it's trying to open it twice. So I disabled one of them...

 

[fsphil]

I haven't added audio yet. Each line of the GRC flow graph does a different function, one is for viewing locally (ends with SDL), one of the lines that ends with the osmocom is for UHF PAL (terrestrial) and the third is for FM PAL (satellite). You should only enable one of the osmocom lines at a time.

The C encoder is making good progress. I'm hoping to add audio to that.

 

[fsphil]

I can push up the audio/nicam stuff I have from previous experiments but it's really unfriendly code

 

[Captain Jack]

Go for it - this new experimentation is opening my eyes into the highly technical aspects of analogue transmissions.

Have you done any more development on DMAC (or even DMAC)? Though your BSB receiver is DMAC only I believe...

 

[fsphil]

Yeah, D-MAC only at the moment. I'm on the look out for a D2 receiver.

The work at the moment is trying to get valid (but empty) audio packets into the data burst. I've still not managed to convince my receiver that it's seeing a valid signal. It's either:
* I've not implemented enough of the standard.
* I've implemented something wrong. (likely)
* The receiver is faulty. (unlikely)

Work continues

 

[Captain Jack]

There's this: PACE MRD960 PLUS Satellite Analogue Receiver | eBay

He has two available but postage is a little pricey as it's located in Cyprus. I was looking at getting it as it's brand new - maybe if we both get it, we can save on postage?

Alternatively, I am more than happy to let you borrow my Pace receiver and Philips decoder to play with

 

[2cvbloke]

There's this: PACE MRD960 PLUS Satellite Analogue Receiver | eBay

Looks familiar...

I was perusing ebay earlier and found this Pace MRD960 MAC decoder apparently new-in-box for sale:

http://www.ebay.co.uk/itm/131104349006

And at the time of posting, there's two for sale (no, I didn't buy the already sold one!!!), dunno if they're any good for play, but maybe worth a look...

 

[scopus]

Go for it - this new experimentation is opening my eyes into the highly technical aspects of analogue transmissions.

Have you done any more development on DMAC (or even DMAC)? Though your BSB receiver is DMAC only I believe...

I had a Philips BSB receiver converted to D2 MAC by a company called Transworld near Whitby, long gone now though. It worked with Filmnet Tv1000 etc with no problem.

 

[Captain Jack]

Yeah, I had a Ferguson one - that was awful. Took forever to lock and decode.

 

[PaulR]

I had a Philips BSB receiver converted to D2 MAC by a company called Transworld near Whitby, long gone now though.

So did I!

IIRC there was also an on-board terrestrial TV tuner that could be used in France. It was a great way for me to feed the SECAM transmissions through to my TV at the time.

 

[fsphil]

Not totally on topic, but I've released the C version of my PAL/NTSC encoder. It's up at GitHub - fsphil/hacktv: Analogue TV transmitter for the HackRF
Just AM modulation so not for satellite receivers yet. It's my goal to eventually add SECAM and D/D2-MAC to this too.

 

[Captain Jack]

Hi Phil, this is truly impressive work and works great from just about any source I throw at it. One slight "bug" that I've found is that the repeat function doesn't seem to work on my setup:

parallels@ubuntu:~/hacktv$ ./hacktv -f 855250000 -m i -g 47  /media/psf/Home/Downloads/FilmNet+\ ident\ from\ 1996.mp4 -r
Video: 832x576 25.00 fps (full frame 1024x625)
Sample rate: 16000000
Opening '/media/psf/Home/Downloads/FilmNet+ ident from 1996.mp4'...
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/media/psf/Home/Downloads/FilmNet+ ident from 1996.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isomavc1mp42
    creation_time   : 2007-10-05 22:49:00
  Duration: 00:00:25.68, start: 0.000000, bitrate: 622 kb/s
    Stream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 119 kb/s (default)
    Metadata:
      creation_time   : 2007-10-05 22:49:00
      handler_name    : (C) 2007 Google Inc. v06.24.2007.
    Stream #0:1(und): Video: h264 (Baseline) (avc1 / 0x31637661), yuv420p, 480x360 [SAR 1:1 DAR 4:3], 500 kb/s, 25 fps, 25 tbr, 25k tbn, 50k tbc (default)
    Metadata:
      creation_time   : 2007-10-05 22:49:00
      handler_name    : (C) 2007 Google Inc. v06.24.2007.
UU

[starts transmitting file at this stage]
[at the end of the file, it prints a ton of Us but no more output from HackRF]

UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU.....

Would be amazing to see a D2MAC implementation of this! With audio