Carousel Erase flag bugfix

Fix a minor bug in status flag bits where in certain conditions the Erase flag was erroneously removed from a subpage

Bugfixes, log verbosity, and datacast API preview

This release includes:

• Small bugfixes for the TCP packetserver, and tidied up includes.
• Tweaks to the internal clock code to make the generated packet stream run closer to the system clock time.
• The verbosity of log output is now controlled by the --debug <level> argument. This takes a value between 0 (none) and 5 (verbose debug message).
• Added Nemetext to available services.

This release also contains an experimental preview of a databroadcasting server, which can be enabled with the new --datacast <port> argument. The API currently supports inserting IDL format A or raw packet data on datachannels 1-15, but is subject to change before release.
A new datacast_lines parameter in vbit.conf sets how many lines per field are dedicated to datacast packet output. If this is absent or set to zero, datacast lines will replace filler packets within the main service instead.

Bugfix

Fix a bug preventing recalculation of page CRCs when carousels changed

Integrated packet server

New features

This release adds a simple TCP packet server for feeding packet data to microcomputer emulators etc. Entire fields of t42 data are transmitted to up to five clients. Blank lines are filled with null bytes.

The server is enabled with a new --packetserver argument which requires a valid port number.

In addition a new output format none has been added which disables the standard output when only a packet server is required.

Bug fixes

Some of the hard crashes have been fixed in the TCP command interface in this release, however it is still substantially unfinished/broken.

DVB improvements

Make DVB output simpler to use by encapsulating DVB-TXT packets in an mpeg transport stream.

This provides two new output formats ts and tsnpts to generate an encapsulated DVB-TXT stream with or without program clock reference and presentation timestamps respectively.

The PID of the teletext stream may be set using the --pid argument which accepts a decimal integer.

The previous un-encapsulated PES output format is removed in this release.

Page checksums

This release finally implements page checksums to keep BBC micro teletext adapters and any future VHS teletext recoverers happy 😉

A known issue with this implementation is that dynamically generated substitutions used on the Teefax world clock, and system status page are transmitted with an incorrect CRC.

Minor release

Add the ability to set a custom header for a magazine through special page files to support ancillary services with a different identity to the main service.

New vbit-config and DVB output

Ground-up rewrite of vbit-config to implement missing features
Add alternate output formats including Packetised Elementary Streams for DVB
Implement cycle mode carousel timings
New clock synchronisation and output packet throttling code
Miscellaneous fixes and minor features

New Ceefax regions

Adds Wales and London Ceefax regions to known services
Implement page coding type 4 for TOP Additional Information Tables
Implement per packet coding (type 5)

Minor changes to scripts

This update tidies up the systemd unit files for Raspberry Pi systems and adds symlinks to the user's ~/.local/bin directory for vbit2 and the runvbit2.sh script.
The Ceefax (South) region is added to the known services in vbit-config.
Windows users can continue to use the v2.4.0 binary.