T2-MI technical overview
Aug 09, 2024
The DVB-T2 standard allows different modulation parameters to be used for individual programs or groups of programs within a channel.
Programs/groups of programs are fed to the modulator as physical layerpipes (PLP). The associated modulation parameters are transmitted as L1 information. The T2 modulator interface (T2-MI) has been defined.
This serial interface (ASI or IP) enables time division multiplex (TDM) transmission of all channel data, including PLPs and L1 information.
T2-MI packets
All data (BB frames, L1 data, SFN info, FEF and AuxData streams) is packetized as payload into T2-MIpackets. In the T2-MI packet header, the packet_type gives the type of payload data, the payload_len field the payload length in bits. Padding bits are used to align the subsequent CRC32 fi eld byte. The CRC32 and packet_count fi elds make it possible to verify error free transmission of the T2-MI packet.
DVB data piping (T2-MI specific) single PID
T2-MI packets are encapsulated into DVB/MPEG transport stream packets using "data piping" in line with EN 301 192 [4], clause 4. The T2-MI packets are inserted, one after another, into the payload of MPEG-2 TS packets. Each new T2-MI packet is to immediately follow the previous one. A TS packet may contain morethan one T2-MI packet. T2-MI packets that are too big to fi t into the payload of a single TS packet are to be split across multiple TS packets as required. The fi rst byte of a T2-MI packet is signaled by the payload_unit_ start_indicator bit in the transport_packet_header and, in this case, a pointer_fi eld is inserted after the trans port_packet_header or adaptation_fi eld. The value of the pointer_fi eld gives the offset to the start of the fi rstT2-MI packet.
Transport stream
T2-MI packets + null packets + optional PAT, PMT with T2MI_descriptor
DIBSYS MUX7400 T2-MI gateway
MUX7400 DVB-T2 gateway Multiplexer and Re-multiplexer developed for T2-MI gereration for DVB-T2 digital Television
standards. It can encapsulate into a T2-MI stream multi TS stemming from a multiplexer or directly from encoders. MUX7400
DVB-T2 Gateway, can support up to 8 ASI or 512IP inputs and Multiplexing to one T2-MI packets over4* ASI and 2*IP out.
Based on the most widely DVB-T2 Gateway, MUX7400 is compliant with the major transmitter manufacturers guaranteeing a
safe DVB-T2 broadcasting over SFN networks. It can provide an end-to-end regionalization solution using PLP substitution or
PLP aggregation technology
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