First USB DVB-T modulator chipsetThere is interesting new device arrived to marked recently, relatively cheap USB DVB-T modulator (modulator = television transmitter). Device is build upon ITE IT9507 chipset, which is world first DVB modulator chipset aimed for mass production devices for home user segment. There has been FPGA based PCI/USB modulators long time, most notably from company called Dektec. These devices are mostly targeted to research and development having price ticket something too much for home users. IT9507 USB dongle manufactured by HiDes costs under $200 USD currently and price will likely go down in the future.
Chipset family is named as IT9500 and it contains two different chip versions, IT9503 and IT9507. IT9503 offers very limited set of DVB-T transmission parameters (constellation QPSK, code rate 1/2, guard interval 1/4) whilst IT9507 is full featured.
Linux DVB API and driverLinux DVB API does not have support for DTV modulators yet. Adding new commands to API is not very big task as there is almost everything already, due to large amount of supported digital television receivers and standards. Biggest challenge I see is to study how to feed transport stream (TS, video and audio data) to Kernel and then from Kernel to device. I think proper solution is to generate correct TS, that match desired transmission parameters, on userspace and then feed that data via Kernel driver to the device.
Dave Chapman has got GPL'd Linux driver from device vendor and is now porting that to the mainline. His work is available on GitHub:
Bad luck, I got Lubuntu and it's doesn't support the drivers for this thing( Speaking of this issue, I always had problems with driver updates on this OS. Especially GPU ones, because the update center always installs the wrong stuff and after that I'm spending another one evening to backup out of this 800x600 disaster. Good that not so long ago I found out the side-part site where I can manually download Nvidia driver http://driverscenter.com/manufacturers/nvidia Although it's not an official NVidia's site, I don't care because download speed is way faster here and there is none of this additional software that they're usually forcing me to install. Unfortunately, there is no drivers for this modulator. And the years passed, so maybe I sould just forget about it.....ReplyDelete
Superbly written article, if only all bloggers offered the same content as you, the internet would be a far better place.. laihdutusReplyDelete