Views

DVB-T

In addition to the usual IP-based streaming over wired Ethernet and WiFi, all lectures at 28C3 are broadcast via our public, free-to-air DVB-T transmitter, which should cover the whole BCC area. The transmission parameters are as follows (preliminary configuration!):

This means you can bring any DVB-T receiver (including the small USB key sized adapters that you can plug in your laptop) and view the lectures this way. A great solution for high-quality video streams, even if the Wifi is overloaded and you don't have a wired Ethernet connection.

Transmission parameters

Channel	21
Frequency	474 MHz (470-478 MHz)
Bandwidth	8 MHz
FFT-Mode	8K
Constellation	QAM16
Guard Interval	1/4
FEC	2/3
Bitrate	13,27 MBit/s
Transmission Power (ERP)	<6 Watt (7,8 dBW)

Reception

These parts are still preliminary

channels.conf

For viewing with mplayer, put this into .mplayer/channels.conf

Room 1:474000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_AUTO:QAM_16:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_4:HIERARCHY_NONE:256:257:1
Room 2:474000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_AUTO:QAM_16:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_4:HIERARCHY_NONE:512:513:2
Room 3:474000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_AUTO:QAM_16:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_4:HIERARCHY_NONE:768:769:3

and run with

mplayer dvb://"Room 1"

to boost the volume add the following(for 20dB)

-af volume=20:0

VLC

run VLC with the following command line:

vlc --aspect-ratio=16:9 dvb://frequency=474000000

VDR (Video Disc Recorder)

You can also use the VDR (http://www.vdr-wiki.de) Software to watch and record the DVB-T streams of the talks. To have the feeling of watching TV you can use the script from http://www.federationhq.de/projekte/vdr/fahrplan-importer [1] to import the Fahrplan as EPG Data into the VDR and use it for Recording TImer programming. You can find a working channels.conf for VDR there too.

Required Hardware

Any DVB-T receiver will do - use USB sticks, handheld monitors or cellphones with DVB-T function. During the event we will gather information about working USB sticks. Also we will add configuration settings for specific devices and software.

Transmitter Setup

Since the BCC is a steel-concrete structure which is very bad for electromagnetic waves. However the biggest problem was the fact that the USB2 480MBit/s datarate puts a big peak into channel 22 (478-486MHz). Because of that we have moved down one channel. This should improve reception more than any transmitter relocation or power increase.

one box in the backoffice works as quad encoder, multiplexer and sends the MPEG TS via UDP/RTP to the transmitter. Also the PSI tables are inserted here.
the actual transmitter will be located in the dome of room 1. The antenna is in the middle of room 1.