Re: DVB-S2 multistream support

[Antti Palosaari <crope@iki.fi>]

On 12/27/2011 12:12 PM, Christian Prähauser wrote:
>>
>> Yes, I'm meaning something like what it was described there. I think
>> that the code written by Christian were never submitted upstream.
>>
>
> Hello Mauro,
>
> Konstantin drew my attention to this discussion. Indeed, some time ago I wrote
> a base-band demux for LinuxDVB. It was part of a project to integrate support
> for second-generation IP/DVB encapsulations (GSE). The BB-demux allows to
> register filters for different ISIs and data types (raw, generic stream,
> transport stream).
>
> I realized that the repo hosted at our University is down. If there is interest,
> I can update my patches to the latest LinuxDVB version and we can put them on a
> public repo e.g. at linuxdvb.org.
>
> Kind regards,
> Christian.

I have a question which is a little bit off-topic for that thread but I 
would like to ask since I think you could have some idea.

FEC Code Rate is often given as k/n, for example FEC 1/4. But nowadays 
there is also seen 0.x like FEC 0.8.
I have feeling that this is due to new inner coding used, LDPC instead 
of traditional convolutional codes. When convolution codes were used it 
was correct to define 1/2 as basic rate and puncture rest from that. But 
as now with LDPC we have larger blocks we cannot represent so easily. 
For example DTMB uses LDPC(7488,6016) = 6016/7488 = ~0.8034 => FEC 0.8 
is used.

I am adding DTMB support for DVB API and that's why I have to think if I 
extend old k/n FECs or define new ones as FEC 0.4/0.6/0.8.

regards
Antti

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