Manual configuration

The VBIT2 binary generates a teletext packet stream in t42 format on stdout, to be piped to another program such as raspi-teletext.

Alternative output formats can be selected using the --format command line argument:

• t42 – The default 42 byte format.
• raw – As above but includes the three byte clock run-in and framing code. i.e. 45 byte packets.
• ts – An mpeg transport stream containing a DVB-TXT stream with program clock reference(PCR) and presentation time stamps(PTS).
• tsnpts – as ts but omitting PCR and PTS.
• none – Disables stdout output entirely. Intended for use with the --packetserver option.

The pages in the teletext service are loaded from .tti page files in the directory given by the --dir argument on the command line.

For mpeg transport stream output the packet identifier (PID) for the teletext stream can be set with the --pid argument. This argument accepts a decimal integer. The default PID is 32.

The --debug argument takes a value from 0 to 4, which controls how verbose VBIT2 will be on stderr. By default VBIT2 is silent (equivalent to --debug 0).

Configuration settings for the service are read from vbit.conf in the page directory. VBIT2 also checks for a vbit.conf.override file which enables overriding individual settings without altering the main configuration file. (For example where a public service is retrieved from a version control system).

The vbit.conf file is a text based key=value format (ini style). An example is provided in the VBIT2 source.

The following keys are defined:

• header_template – A 32 character string defining the teletext page header.
• initial_teletext_page – Defines the initial page number (and optional subcode) sent in the Broadcast Service Data Packet. Defaults to 100:3F7F.
• row_adaptive_mode – Controls whether VBIT2 should omit blank page rows. Defaults to false
• network_identification_code and country_network_identification – Unique 16 bit hexadecimal codes assigned to television networks in ETSI TR 101 231. Default to 0000.
• full_field – Non-multiplexed teletext transmission. Not currently implemented.
• status_display – A 20 character string sent in the Broadcast Service Data Packet.
• lines_per_field – Specifies the number of VBI lines required per video field. This value must match the rate at which packets are consumed. Defaults to 16.
• magazine_priority – Set the priority of each magazine where 1 is highest priority and 9 is lowest. These are the initial value of internal counters which are used to determine how often a magazine should generate a packet. The values correspond to magazine 8,1,2,3,4,5,6,7. Defaults to 9,3,3,6,3,3,5,6.
  The resulting cycle timings can be observed by setting the debug level to 4.

Magazine specific enhancement data (packet 29) can be configured using special page files.

An integrated TCP packet server can be enabled using the --packetserver argument which requires a valid port number. See Miscellaneous notes.

The control interface server can be enabled using the --interface argument which requires a valid port number. See Control Interface.