DATV-Express Project - January update report

[KenW6HHC]

Art WA8RMC was very busy in January manufacturing a new production batch of DATV-Express boards. Twenty-four assembled PCBA’s were picked up from the nearby assembly vendor on 2016-01-26. The first 4 boards that Art tested all came up OK on that day….and so Art tested the rest of the boards. USA inventory of DATV-Express boards are now full.

The EU distribution center for DATV-Express shipped five boards….all to a new group of hams working on a new DATV repeater in The Netherlands. Art immediately sent another batch of completed boards to the EU distribution center to replenish that inventory location and relieve a back-order from Belgium.

Charles G4GUO has been doing some testing of H.262 and H.265 compression CODECs for video/audio. (BTW – H.262 is just the formal name for MPEG2 CODECs.) H.265 supports HD video very efficiently…essentially twice the compression (averaging one-half the bits per frame) oh H.264. BUT…the H.265 latency is much longer than H.264. Part of the latency problem is (a) the H.265 algorithm looks forward at more video frames before it begins to create a “short hand” compression of each frame and (b) the H.265 compression algorithm is very processing intensive (Charles reported that his four-core 64-bit computer had each core running at nearly 100% of capacity). The new Windows-based programming effort by Charles can capture video/audio from a source, compress it using the FFMPEG codec libraries, turn it into a valid MPEG2 Transport Stream and then send it to the DATV-Express board where it is turned into DVB-S by the FPGA and then transmitted.

This new software is all still being worked on, but does currently supports H.262 (MPEG 2), H.264 (MPEG4-AVC / MPEG4 part 10 ) and H.265 HEVC. At the moment it only supports MPEG1 Layer II sound although Charles will be adding AAC audio.

The capturing is done using Windows DirectShow so in theory just about any device that has DirectShow support will work with it. In practice there is bound to be some device format project team does not have support for. G4GUO has tested it with 2 different Webcams, an Ezcap capture-dongle and of course vMix. It supports the usual range of symbol rates 200K to 8M and the usual frequency range 65 MHz to 2.48 GHz.

On the Yahoo DigitalATV forum, there is a lot of discussion that Hauppauge has now released the drivers for the HD PVR2 model 157210 capture unit for ubuntu. Grant ZL1WTT/VE3 reported that the ubuntu drivers can be obtained at the Hauppauge support download area. But no one has yet said that they have actually used these new linux drivers with DATV-Express and HD PVR 2 unit?? G4GUO suspects that the PVR 2 drivers are source code and may have to be compiled by the installer to be compatible by DATV-Express?? But, perhaps a new distribution by Ubuntu now contains the drivers? (Is they any feedback from readers on this topic?)

Art WA8RMC is off in Florida escaping the snow storms of Ohio and Ken W6HHC is now happily-married and getting ready for ski vacation in the Sierra-Nevada mountains of California at Mammoth.

"project is set to slow speed"....de Ken W6HHC

[G4GUO]

Here is my first attempt!
It will be a miracle if anyone gets it to work other than me.
https://www.dropbox.com/s/97f5g8n9nw3bd ... r.zip?dl=0

- Charles G4GUO

[g0mjw]

It's a Miracle - it worked. A few crashes but huge improvement.

Mike

[G4GUO]

Thanks Mike for finding the first 4 bugs.

I have replaced the version located at the link above with one that won't crash if you have
10 or more media devices on your PC.

I am a bit disappointed that Rob was not able to get it to work very well with his webcams.
So far I have tested it on 2 of my 3 webcams and it worked well. Today I need to search
the house / shed for my 3rd webcam.

- Charles

[ON1AVO]

Charles,

Below my findings.

DATV Express Transmitter
- SW Installation: OK
- Start: errormessage, after OK, Express Transmitter window

Afbeelding 001.jpg (22.55 KiB) Viewed 9393 times

- Videoinput: C920, connected to laptop, device format empty
- Videoinput: internal laptop webcam, SBC1900N, device format empty
- Videoinput: vMix = OK
- Transmit: default Settings

Afbeelding 006.jpg (69.5 KiB) Viewed 9393 times

o Tx Queue: empty????
o Receiver Tandberg TT1220 locked on the signal
o No video output, explation, see TS analyser screenshot

Afbeelding 007.jpg (130.28 KiB) Viewed 9393 times

Just all stuffing Null packets.
- Test receiver Promax PRODIG-5 : no lock

[G4GUO]

Hi,

You need to select a video format
640x480 30 fps RGB24 for the C920 as input
or 720x576 25 fps if you are using vMix output

The sampler can't connect to the video source as it doesn't know
what format the samples are in. Consequently no video is being
transmitted.

Once you have the initial configuration done that problem should go away.

Those Tandberg receivers require a perfectly formatted DVB signal so you may have
problems. Modern receivers are better are coping with out of spec signals.

- Charles

[PA1KW]

It works! This is my experience:
After changing configuration files and press PTT:

DATV-Express crash.png (7.09 KiB) Viewed 9082 times

After starting the application it works:

DATV Express ok.png (10.63 KiB) Viewed 9082 times

I had one crash and was not able to start app and had to reinstall the program. After reinstall and reconfiguring everything is ok! I'm using VMix....

PA1KW DATV Express.png (598.68 KiB) Viewed 9082 times

My configuration is:
Intel i7-2600k 3,4Ghz
Memory 16Gig
Windows 10 – 64bit

73 Koert PA1KW

[PA1KW]

I did try to use my Logitech Quickcam S5500, but i'm receiving the following message:

sample grabber error.png (4.73 KiB) Viewed 9081 times

This are the video settings:

Video Capture settings.png (7.77 KiB) Viewed 9081 times

73 Koert PA1KW

[G4GUO]

Hello Koert,

Glad to hear you are having some luck. The program is not very good
and starting on a system it does not know about hence the original crash.

During tests with GB3KM it was found the repeater only likes PAL frame rate
and resolution images so I put a filter in the code that would have rejected
your 15 fps camera. Hence the reason you get the message. If you had selected
a 640 x 480 30 fps device it probably would have worked.I guess I should
add a message that says something like "No suitable video capture device selected".

I stretch the image from 640x480 to 720x576 in software. KM thought the
original image was NTSC (we think).

- Charles

[PA1KW]

Thanks Charles,
The Logitech webcam is an old one and 15 is the maximum it is supporting.

QuickcamS5500.png (13.31 KiB) Viewed 9029 times

It is time to buy a new one.

73 Koert PA1KW