VRT.jl

VITA Radio Transport in Julia

VRT.jl provides support for reading and writing VITA 49 streams in pure Julia. It is a very young package, and by no means supports all of the features of VITA 49.2.

Quick start

VRT.jl is not yet registered, so you will need to use the Pkg package to install it.

pkg> add https://github.com/maleadt/VRT.jl

After importing the package, you can read packages from a stream by using the read function, and write them back using the write function:

julia> io = ...

julia> read(io, AbstractVRTPacket)
VRTContextPacket(
  ...
)

julia> write(io, VRTContextPacket(...))

To create a new packet, use the appropriate constructor to create an initial object, and then use @set from Accessors.jl to initialize the immutable fields (using the field hierarchy as shown in the output, whic follows the packet structure as defined in the spec):

julia> packet = VRTContextPacket()
VRTContextPacket(
  # prologue
  header: VRTPacketHeader(
    packet_type: VRT_PT_CONTEXT
    has_class_id: false
    indicators: VRTPacketIndicators(
      nd0: false
      tsm: false
    )
    tsi: VRT_TSI_NONE
    tsf: VRT_TSF_NONE
    packet_count: 0
    packet_size: 0
  )
  stream_id: 0

  context_fields: VRTFields()
)

julia> packet = Accessors.@set packet.header.indicators.nd0 = true
VRTContextPacket(
  header: VRTPacketHeader(
    indicators: VRTPacketIndicators(
      nd0: true
    )
)

For more complicated fields that require setting multiple fields or specially-encoded values, such as the timestamp, functions are provided to help you:

julia> VRT.set_timestamp(packet, Dates.now())
VRTContextPacket(
  header: VRTPacketHeader(
    tsi: VRT_TSI_UTC
    tsf: VRT_TSF_REAL_TIME
  )
  timestamp: 2025-03-20T13:30:37.704 TAI
    integer part: 1742477400
    fractional part: 703999996185
)