[vdr] multistream support in VDR

Manu Abraham abraham.manu at gmail.com
Wed Jan 2 18:52:53 CET 2013


On Wed, Jan 2, 2013 at 10:54 PM, Klaus Schmidinger
<Klaus.Schmidinger at tvdr.de> wrote:
> On 02.01.2013 18:20, Manu Abraham wrote:
>>
>> On Wed, Jan 2, 2013 at 10:34 PM, Klaus Schmidinger
>> <Klaus.Schmidinger at tvdr.de> wrote:
>>>
>>> On 02.01.2013 16:01, Goga777 wrote:
>>>>
>>>>
>>>> Hi
>>>>
>>>> Recently in kernel was added full multistream support (DTV_STREAM_ID)
>>>> https://patchwork.kernel.org/patch/1351421/
>>>>
>>>> is there any plans to implement multistream support in vdr ?
>>>
>>>
>>>
>>> DTV_STREAM_ID is already used in VDR for DVB-T2.
>>
>>
>> The current DVB-T2 support is with CXD2820. CXD2820 supports only a single
>> TS.
>> The only demodulators in kernel that supports Multiple Input Stream
>> (MIS) are the
>> STV0900 and the STV0903.
>
>
> I'm afraid I don't quite know what "Multiple Input Stream" means.
> Can somebody explain this in a few words?

According to the specification:

5.1.6 Base-Band Header insertion
A fixed length base-band Header (BBHEADER) of 10 bytes shall be inserted
in front of the DATA FIELD, describing its format (the maximum efficiency loss
introduced by the BBHEADER is 0,25 % for nldpc = 64 800 and 1 % for
nldpc = 16 200 assuming inner code rate 1/2).

MATYPE (2 bytes): describes the input stream(s) format, the type of
Mode Adaptation and the transmission Roll-off factor, as explained in table 3.

First byte (MATYPE-1):
 TS/GS field (2 bits): Transport Stream Input or Generic Stream Input
(packetized or continuous).
 SIS/MIS field (1 bit): Single Input Stream or Multiple Input Stream.

It simply means whether there exists a Single TS or a hierarchially modulated
multiple TS. Basically, you can have 2 DVB-T streams with the device.

If you have multiple streams, then you need to specify the Stream ID for which
you need the to filter it out. Something like an IP address and it's
Subnet Mask,
in network terminology.

In effect we are not reading the BBheader directly. So this is a bit
clumsy to use.
But anyway for simple usage, one can simply set the Stream ID alone.

I have not seen any MIS being flagged, except that I was told that it was done
only in field trials rather than in the practical world. I was
surprised to find
someone found that there was 1 or 2 Transponders on some Russian bird
which flagged MIS.



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