[Fwd: Re: [linux-dvb] [PATCH] Multi protocol support (stage #1)]

Manu Abraham abraham.manu at gmail.com
Thu Apr 27 13:32:07 CEST 2006



-------- Original Message --------
Subject: 	Re: [linux-dvb] [PATCH] Multi protocol support (stage #1)
Date: 	Thu, 27 Apr 2006 10:33:38 +0200 (CEST)
From: 	Patrick Boettcher <patrick.boettcher at desy.de>
To: 	Manu Abraham <abraham.manu at gmail.com>
CC: 	linux-dvb <linux-dvb at linuxtv.org>
References: 	<444E17BA.4070805 at gmail.com>



Hi Manu,

linuxtv seems to be down currently, would you please bounce my answer in
that case.


On Tue, 25 Apr 2006, Manu Abraham wrote:

> Hi All,
> 
> Revised patch again.

+enum fe_stream {
+       FE_STREAM_HP                    = 0x00000001,
+       FE_STREAM_LP                    = 0x00000002
+};

[..]

+enum fe_bandwidths {
+       FE_BANDWIDTH_QUERY              = 0x00000000,
+       FE_BANDWIDTH_8_MHZ              = 0x00000001,
+       FE_BANDWIDTH_7_MHZ              = 0x00000002,
+       FE_BANDWIDTH_6_MHZ              = 0x00000004,
+       FE_BANDWIDTH_AUTO               = 0x10000000
+};

In DVB-H other bandwidth can be used. IMHO, it would be more useful to
specify the bandwidth in MHz, instead of have defines.

+enum fe_inversion {
+       FE_INVERSION_QUERY              = 0x00000000,
+       FE_INVERSION_OFF                = 0x00000001,
+       FE_INVERSION_ON                 = 0x00000002,
+       FE_INVERSION_AUTO               = 0x10000000
+};

Afaik, at least for DVB-T/H, Inversion is not a real tuning parameter.
There is not reason for a broadcaster to send the inverted spectrum... the
inversion-switch I saw so, was always only because of the tuner-output. So
in fact the inversion differences have been caused by different designs.

>From the tuning point of view inversion should be always AUTO. 

+enum fe_hierarchy_info {
+       FE_HIERARCHY_QUERY              = 0x00000000,
+       FE_HIERARCHY_NONE               = 0x00000001,
+       FE_HIERARCHY_1                  = 0x00000002,
+       FE_HIERARCHY_2                  = 0x00000004,
+       FE_HIERARCHY_4                  = 0x00000008,
+       FE_HIERARCHY_AUTO               = 0x10000000
+};

Those setting seem to come from a modulator-menu ;).

Maybe hierarchy on/off and another parameter alpha is better, or like
this:

+enum fe_hierarchy_info {
+       FE_HIERARCHY_QUERY              = 0x00000000,
+       FE_HIERARCHY_OFF                = 0x00000001,
+       FE_HIERARCHY_ON_ALPHA_1         = 0x00000002,
+       FE_HIERARCHY_ON_ALPHA_2         = 0x00000004,
+       FE_HIERARCHY_ON_ALPHA_4         = 0x00000008,
+       FE_HIERARCHY_AUTO               = 0x10000000
+};

What do you think? In conjuntion with fe_stream we finally can really use
hierarchy mode with linux-dvb.

+enum fe_mpefec{
+       FE_MPEFEC_ON                    = 0x00000001,
+       FE_MPEFEC_OFF                   = 0x00000002,
+};
+
+enum fe_timeslicing {
+       FE_TIMESLICING_ON               = 0x00000001,
+       FE_TIMESLICING_OFF              = 0x00000002
+};

Hmm, OK, What about AUTO for timeslicing and mpefec.

+/**
+ *     DVB-T parameters
+ */
+struct dvbt_params {
+       enum fe_modulations             constellation;
+       enum fe_bandwidths              bandwidth;
+       enum fe_fecrates                code_rate_HP;
+       enum fe_fecrates                code_rate_LP;
+       enum fe_transmit_modes          transmission_mode;
+       enum fe_guard_intervals         guard_interval;
+       enum fe_hierarchy_info          hierarchy;
+};
+
+/**
+ *     DVB-H parameters
+ */
+struct dvbh_params {
+       enum fe_modulations             constellation;
+       enum fe_bandwidths              bandwidth;
+       enum fe_fecrates                code_rate_HP;
+       enum fe_fecrates                code_rate_LP;
+       enum fe_transmit_modes          transmission_mode;
+       enum fe_guard_intervals         guard_interval;
+       enum fe_hierarchy_info          hierarchy;
+       enum fe_mpefec                  mpefec;
+       enum fe_timeslicing             timeslicing;
+};

In hierarchy mode, how to select the HP or LP stream?

I think for dvbh and dvbt we need to add:

+       enum fe_stream                  stream;

Default should be always the HP-stream.

Sorry for being so short - but vacation is waiting :)

best regards,
Patrick.

--
Mail: patrick.boettcher at desy.de
WWW:  http://www.wi-bw.tfh-wildau.de/~pboettch/






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