Multistream and Physical Layer Scrambling Support with the Max SX8 Pro (Linux DVB API)

Multistream and Physical Layer Scrambling Support with the Max SX8 Pro (Linux DVB API)

The Max SX8 (not the Basic version) supports the following advanced features when using the Linux DVB API:

1. Multistream (MIS)

• Property: DTV_STREAM_ID
• Function: Selects a specific stream in multistream transmissions.
• Note:
  • Setting DTV_STREAM_ID = 0x80000000 activates the bbframe mode.
  • In this mode, the tuner outputs all baseband frames (bbframes) encapsulated in transport stream (TS) packets.
  • Streams must be manually demultiplexed and parsed by the application.

2. Physical Layer Scrambling (PLS)

• Property: DTV_SCRAMBLING_SEQUENCE_INDEX
• Function: Sets the gold code required for physical layer scrambling.
• Note:
  • If only the PLS root code is known, it can be converted to a gold code using a simple formula.

Conversion of root code and gold code available at the following link:
https://download.digital-devices.eu/download/dokumentation/plscode-converter/s2pls.html 

Example: Converting Root Code to Gold Code

The conversion uses the following formula:

Gold Code = (Root Code << 2) | 1

Example:
Given root code: 0x1AC (decimal: 428)

Gold Code = (0x1AC << 2) | 1
          = 0x6B0 | 1
          = 0x6B1

Result: The value to set via DTV_SCRAMBLING_SEQUENCE_INDEX is 0x6B1.

This formula follows the DVB-S2 standard: The root code is multiplied by 4 (left shift by 2 bits) and the lowest bit is set to 1.

Important:
These advanced features are available only with the Max SX8 PRO.
The Basic version does not support Multistream or Physical Layer Scrambling.