Re: DVB-S2X - S2 Extensions Support

[Mauro Carvalho Chehab <mchehab@s-opensource.com>]

Em Thu, 30 Nov 2017 15:24:47 +0200
Αθανάσιος Οικονόμου         <athoik@gmail.com> escreveu:

> Hi All,
> 
> I am not aware if there was a discussion regarding S2X before, so I
> would like to hear what are your plans regarding S2X.

Ralph started a discussion about that sometime ago.

> There are already several manufacturers with S2X capable receivers and
> soon more will follow.
> 
> The S2 extensions will bring more code rates and modulations, so I
> guess adding those to fe_code_rate and fe_modulation is mandatory.
> 
> Something like the following with proper documentation of course.
> 
> @@ -313,6 +313,24 @@ enum fe_code_rate {
>         FEC_3_5,
>         FEC_9_10,
>         FEC_2_5,
> +       FEC_13_45,
> +       FEC_9_20,
> +       FEC_11_20,
> +       FEC_23_36,
> +       FEC_25_36,
> +       FEC_13_18,
> +       FEC_26_45,
> +       FEC_28_45,
> +       FEC_7_9,
> +       FEC_77_90,
> +       FEC_32_45,
> +       FEC_11_15,
> +       FEC_1_2_L,
> +       FEC_8_15_L,
> +       FEC_3_5_L,
> +       FEC_2_3_L,
> +       FEC_5_9_L,
> +       FEC_26_45_L
>  };
> 
> @@ -350,6 +368,10 @@ enum fe_modulation {
>         APSK_32,
>         DQPSK,
>         QAM_4_NR,
> +       APSK_8,
> +       APSK_64,
> +       APSK_128,
> +       ASPK_256
>  };

That's the easiest part :-)

> Adding new values, means that we should bump the DVB API as well to
> 5.12 in order usespace applications to be aware of the changes.

Yes.

> That is let's say the easy part, the hard part is how are we going to
> query frontend capabilities?
> 
> Are we going to introduce a new delsys (SYS_DVBS2X)? Or are we going
> to introduce Supports "3nd generation" modulation"
> (FE_CAN_3G_MODULATION) ?
> 
> Or since the new APSK modulations are optional, we need to add
> FE_CAN_APSK_8/64/128/256 to capabilities.
> 

We have only 2 bits (maybe a few more bits, if we reuse some
unused ones). Anyway, that's not enough for FE_CAN_foo flags.
So, we'll need to extend the API somehow. I'm answering the other
thread with some raw ideas for discussion.

> Thanks for your suggestions.
> 
> Best Regards,
> Athanasios
> 
> PS. Here you can read about S2X:
> https://www.dvb.org/standards/dvb-s2x
> http://www.dvb.org/resources/public/standards/a83-2_dvb-s2x_den302307-2.pdf



Thanks,
Mauro