Re: [PATCH RFCv3] dvb: Add DVBv5 properties for quality parameters

[Antti Palosaari <crope@iki.fi>]

On 01/01/2013 06:48 PM, Manu Abraham wrote:
> On Tue, Jan 1, 2013 at 8:30 PM, Mauro Carvalho Chehab
> <mchehab@redhat.com> wrote:
>
>> [RFCv4] dvb: Add DVBv5 properties for quality parameters
>>
>> The DVBv3 quality parameters are limited on several ways:
>>          - Doesn't provide any way to indicate the used measure;
>>          - Userspace need to guess how to calculate the measure;
>>          - Only a limited set of stats are supported;
>>          - Doesn't provide QoS measure for the OFDM TPS/TMCC
>>            carriers, used to detect the network parameters for
>>            DVB-T/ISDB-T;
>>          - Can't be called in a way to require them to be filled
>>            all at once (atomic reads from the hardware), with may
>>            cause troubles on interpreting them on userspace;
>>          - On some OFDM delivery systems, the carriers can be
>>            independently modulated, having different properties.
>>            Currently, there's no way to report per-layer stats;
>
> per layer stats is a mythical bird, nothing of that sort does exist. If some
> driver states that it is simply due to lack of knowledge at the coding side.
>
> ISDB-T uses hierarchial modulation, just like DVB-S2 or DVB-T2

Manu, you confused now two concept (which are aimed to resolve same real 
life problem) - hierarchical coding and multiple transport stream. Both 
are quite similar on lower level of radio channel, but differs on upper 
levels.

Hierarchical is a little bit weird baby as it remuxes those lower lever 
radio channels (called layers in case of ISDB-T) to one single mux! 
There is only single TS which demodulator is responsible to remux all 
those 3 physical "layer" channels, which could be modulated differently. 
So after demodulation you really has a TS which contains stream that has 
different statistics. That's opposite to compared for multiple TS 
principle used for DVB-T2/S2. In case of multiple TS you have same 
statistics for whole TS (but naturally there could be multiple TS after 
demodulation).

regards
Antti

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