DATV-Express Project – July update report

[KenW6HHC]

Charles G4GUO received his ODROID U3 ARM-based micro-PC and began testing. He reported that the quadcore-ARM microprocessor running at 1.7 GHz has plenty of speed (compared to the Raspberry Pi) and the software repository by ODROID team has all the software needed to compile the kernel, etc. You can see in the picture below that the ODROID U3 comes standard with a large heatsink, and Charles reports the unit runs only warm, and there is no need for the optional fan kit. Charles is still learning how to spread out the processing load evenly over the four cores and is currently playing with the priority of the threads. One advantage of the quadcore-ARM on ODROID-U3 is the CPU speed(s) is fast enough to allow performing DVB-T 2 MHz bandwidth with full 4096 point iFFT math so that there are no nearby alias spurs.


Size of quadcore-ARM ODROID-U3 board is about the same size as Raspberry Pi

Charles has been adding code to allow the DATV-Express software to accept video streams using the UDP protocol. There is a lot of complexities involved but the current project preference is to let the video application (like VLC or FFMPEG) set-up all the PIDs, bit data-rate, etc. This effort is not completed, yet.

The project team has still not heard of any further progress by Hauppauge on releasing a linux driver for their new HVR-1955/HVR-1975 MPEG2 encoder products. So Charles has looked at an alternative video-capture USB-device to perform the MPEG2 encoding for DATV. The EasyCAP (aka EZCAP) is a video-capture product that has been around for a long time. Unfortunately, there are at least five different chip-sets that are being used to manufacture these devices…some work on linux, and others do not work. The chip set by Syntek called STK-1160 works OK, but there is a variation of that chip set that only supplies 8K audio?? A chip set called SAA-7113 works well also. The EasyCAP problem is that the sellers on e-bay or Amazon have no idea which chip set is being used in the product they sell. So the buy has to plug the device into the computer to identify what USB sees as the chip set. At $15 apiece (plus shipping), they are cheap enough to throw away if you get a wrong chip set. But, the project team needs to sort these chip set issues out and see if we can find a good supplier….before we release this EasyCAP code.

The project team has decided to not allow further research of EZCAP to hold up the release of the ARM code for DATV-Express for the ODROID-U3. Charles plans to move forward on preparing a Debian package to install the latest code for DATV-Express, including an installation for ARM that has been tested on ODROID-U3. Ken W6HHC has now received his ODROID and will begin testing Debian packages as soon as he returns from vacation towards the end of August. Charles plans to provide a DATV-Express presentation at BATC General Meeting in September. Ken plans to provide a DATV-Express presentation at TAPR Digital Comm Conference in September.

“moderate speed ahead”….de Ken W6HHC