mirror of
https://github.com/DigitalDevices/dddvb.git
synced 2023-10-10 13:37:43 +02:00
105 lines
3.0 KiB
Plaintext
105 lines
3.0 KiB
Plaintext
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
|
||
an MPEG2 transport stream.
|
||
|
||
This feature is available on supported cards as firmware update and
|
||
is currently considered experimental.
|
||
|
||
Supported hardware:
|
||
|
||
Cine V7A (>=1.7 FW)
|
||
OctopusCI S2 Pro Advanced (>=1.7 FW)
|
||
Duoflex S2 v4 Advanced (TBA)
|
||
MaxSX8 (NOT the MAXS8!)
|
||
|
||
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)
|
||
|
||
|
||
Current FPGA images (including FW 1.7 for the above mentioned cards)
|
||
can be found here:
|
||
|
||
http://download.digital-devices.de/download/firmware/html/firmwareupdate.html
|
||
|
||
|
||
|
||
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.
|
||
|
||
|
||
|
||
Because there were some questions why we use this data format,
|
||
here are some examples for why using this format this makes handling BBFrames easier:
|
||
|
||
- The start of a frame is easily found because a new set of sections is
|
||
started.
|
||
|
||
- Existing software layers like the Linux kernel DVB demuxer can be used unchanged.
|
||
|
||
- Existing hardware like the OctopusNet SAT>IP server which can only handle TS packets can
|
||
stream BBFrames via SAT>IP with this method.
|
||
|
||
- There is at least one demodulator (e.g. on the MaxSX8) which supports this format in hardware.
|
||
|
||
|
||
|
||
|
||
|
||
|