DDS(Diretta Direct Stream) are network packets PURE filled with audio streams
it approaches Pure Audio
DDS(Diretta Direct Stream) are network packets PURE filled with audio streams
it approaches Pure Audio
Network audio is typically built on top of IP (Internet Protocol).
When utilizing Ethernet, arbitrary protocols are built on top of standardized protocols.
This imposes constraints on communication within the OS and Ethernet.
IP includes IPv4 and IPv6, with TCP and UDP existing on top of them.
Diretta utilizes IPv6/UDP, but many audio protocols use IPv4/TCP.
Some protocols claiming high sound quality utilize UDP.
The address length is 32 bits for IPv4 but 128 bits for IPv6, increasing the data volume.
However, there are several differences in their processing.
IPv4 requires consulting a transmission table to determine the Network Interface for communication,
and its variable-length header necessitates this determination.
Additionally, AutoIP issues cause address resolution delays at startup, requiring this process to run constantly.
Therefore, Diretta adopts IPv6.
TCP (Transmission Control Protocol) and UDP (User Datagram Protocol)
differ in whether flow control and packet loss handling are included within the protocol itself or handled by the user, as their names suggest.
Diretta handles all communication control, so UDP is used.
IPv6/UDP has a 48 byte header, and the Diretta Header is 16 bytes, resulting in a total header size of 64 bytes.
Through Diretta MSmode optimization, some functions of the Diretta Header/Footer are reassigned to the UDP Port Number, compressing the header to 1 or 2 bytes (49 or 50 bytes total).
This 1 byte difference exists to maintain memory alignment during transmission (MSmode1 or MSmode2) (MS stands for Multi Stream, but the name has no meaning).
UDP calculates a checksum, and similarly, the Ethernet Frame performs CRC calculation.
In the case of Link Local IPv6 addresses, they are generated from the MAC address, and the Ethernet Frame also contains a MAC Address.
Within Diretta, a protocol specialized for high-end audio, these parts were deemed redundant and optimizable.
DDS eliminates these redundant parts by creating a new protocol to replace IP, processing Ethernet frames directly into Direat within Diretta.
This reduces the header to 2 bytes. (These 2 bytes represent minimal control.)
Adding 2 bytes to the 14 byte Ethernet Frame II header places the audio data at a 64 bit alignment position, optimizing subsequent processing for the CPU architecture.
