From c07e4bebbdd43ef3cde4c571a6add4de3b9393f3 Mon Sep 17 00:00:00 2001 From: Ralph Metzler Date: Fri, 15 Dec 2017 00:25:51 +0100 Subject: [PATCH] add documentation about bb frame mode --- docs/bbframes | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) create mode 100644 docs/bbframes diff --git a/docs/bbframes b/docs/bbframes new file mode 100644 index 0000000..78f57f1 --- /dev/null +++ b/docs/bbframes @@ -0,0 +1,75 @@ +To allow the transport of DVB-S2 baseband frames (BBFrame) across existing hard- and software +interfaces, we have added the ability to embed the BBFrame data into a MPEG2 transport stream. +This is available on supported cards as firmware update. + +This feature is currently considered experimental. + +Supported hardware: + +Cine V7A (>=1.7 FW) +OctopusCI S2 Pro Advanced (>=1.7 FW) +Duoflex S2 v4 Advanced (TBA) + +The following cards are based on the broadcast version of the +DVB-S2 demodulator. The BBFrame output is working but +not documented. We therefore can not guarantee the +feature will work under all conditions. + +cineS2 V7 (>=1.7 FW) +OctopusCI S2 Pro (>=1.7 FW) +Duoflex S2 v4 (TBA) + + + +Packet format: + +The BBFrames are packetized into MPEG2 private sections (0x80), one section per transport stream +packet. The PID is fixed at 0x010E. + + +Header packet of frame: + +0x47 0x41 0x0E 0x1X 0x00 0x80 0x00 L 0xB8 BBHeader (169 * Data) + +L: Section Length, always 180 (0xB4) +BBHeader: 10 Bytes BBFrame header (see DVB-S2, EN-302307) +Data: 169 Bytes of BBFrame payload + + +Payload packets: + +0x47 0x41 0x0E 0x1X 0x00 0x80 0x00 L N (179 * Data) + +L: Section Length, always 180 (0xB4) +N: Packet counter, starting with 0x01 after header packet +Data: 179 Bytes of BBFrame payload + + +Last packet: +0x47 0x41 0x0E 0x1X 0x00 0x80 0x00 L N ((L-1) * Data) ((180 – L) * 0xFF) + +L: Section Length, remaining Data – 1, (0x01 .. 0xB4) +N: Packet counter +Data: L-1 Bytes of BBFrame payload + + + +Automatic detection of input format: + +The bridge firmware allows automatic detection of the incoming data. +To receive regular transport streams in this formats it is still required to setup +the DVB-S2 demodulator to output BBFrames instead of regular TS Packets. +When enabled the embedding mode is automatically turned on or off depending on incoming data +from the DVB-S2/S2X frontend. The decision depends currently only on the first byte of a packet. +If it is 0x47 it switches to transport stream mode else it switches to embedding mode. + +Note that 0x47 can currently not occur in the first byte of a BBFrame header if all reserved +values of DVB-S2 and -S2X are observed. + + + + +API: + +Currently DTV_STREAM_ID is misused. +Set it to 0x80000000 to enable frame mode in the demod.