Today, I checked if the VASE framework can handle DVB-T2 as well as DVB-T via its internal DVB support for Linux. So, I tested with WIT and identified open issues which hamper the watching of DVB-T2 channels.
- First of all, I searched which station is the nearest one. In my case, it is „Fernmeldeturm Stuttgart“, which is less than 20 km from here.
- I searched the Internet for a complete channel list and found: http://www.dvb-stuttgart.de. But this doesn’t tell anything about DVB-T2. So, I decided to do some channel scans with „w_scan“ under Linux. Fortunately, I bought some new equipment some days ago:
„DVBSky T680C V2 USB“ as DVB-T/T2/C receiver:
„Vega AVK25 Plus“ as antenna:
- The resulting list with all found DVB-T2 and DVB-T channels is stored in „channels.conf“ format: channels_dvbt2_stuttgart.conf
(I also published this list here: http://www.vdr-wiki.de/wiki/index.php/Channels.conf_DVBT-De-Baden-W%C3%BCrttemberg-Stuttgart)
- Based on my new channel list, I was able to debug the parser in VASE, which handles a channels.conf file. After adding a couple of code lines regarding the parsing of the „S1“ channel parameter, it was able to distinguish between DVB-T and DVB-T2 entries. I ended up with a correct channel list in memory.
- However, the DVB channel switch did not work properly yet. I had to extend the command sequence which gets sent via „FE_SET_PROPERTY“ towards the DVB frontend:
- For DVB-S2 and DVB-T2 a new parameter called „DTV_STREAM_ID“ was introduced in the LinuxTV API to support multiple sub streams for a single transport stream.
- Additionally, my hardware (or only the driver, I am not sure at this point) does not support the I/O call „FE_READ_SIGNAL_STRENGTH“ and others, which are typically used in VASE to check the result of a channel switch. Some new code lines do now the auto-detection of this case and avoid further warnings and aborts.
At this point, I had reached my goal and got some first pictures from the German DVB-T2 channel „Zweites Deutsches Fernsehen“. A benefit of the VASE framework in this situation is the support for hardware accelerated video decoding. It uses the great FFmpeg API with its „cuvid“ decoders for Linux. As result of this, VASE allows a smooth playback of DVB-T2 channels and the applied HEVC codec also on standard PCs.