DVBv5 (S2API) API for DVB-T | |
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Hi Steve and others,I was quite busy recently and only found now the time to do what I should have done some time ago as it turned out. I could beat myself.
When I checked how DVB-T is now implemented I saw that there is one thing which was wrong in the DVBv3 API already and is still in DVBv5.
It is regarding hierarchical transmissions and the selection of high-priority and low-priority streams. This was not possible with DVBv3.
I quickly changed how I think it should be done and the resulting patch can be found attached.
The worst is, that this patch changes the frontend.h and thus the user interface. I put some comments in the code I wrote which hopefully helps to understand why I think this is necessary.
I hope it is not too late to apply this and to go for 2.6.28 . If it is, my bad and everyone can blame me for not having a proper hierarchical mode implemented.
Sorry again, Patrick. -- Mail: patrick.boettcher@xxxxxxx WWW: http://www.wi-bw.tfh-wildau.de/~pboettch/
diff -r e2a8b9b9c294 linux/drivers/media/dvb/dvb-core/dvb_frontend.c
--- a/linux/drivers/media/dvb/dvb-core/dvb_frontend.c Fri Oct 17 19:45:55 2008 +0300
+++ b/linux/drivers/media/dvb/dvb-core/dvb_frontend.c Sun Oct 19 18:42:53 2008 +0200
@@ -845,6 +845,7 @@
.cmd = DTV_DELIVERY_SYSTEM,
.set = 1,
},
+
[DTV_HIERARCHY] = {
.name = "DTV_HIERARCHY",
.cmd = DTV_HIERARCHY,
@@ -862,16 +863,6 @@
.set = 1,
},
#endif
- [DTV_CODE_RATE_HP] = {
- .name = "DTV_CODE_RATE_HP",
- .cmd = DTV_CODE_RATE_HP,
- .set = 1,
- },
- [DTV_CODE_RATE_LP] = {
- .name = "DTV_CODE_RATE_LP",
- .cmd = DTV_CODE_RATE_LP,
- .set = 1,
- },
[DTV_GUARD_INTERVAL] = {
.name = "DTV_GUARD_INTERVAL",
.cmd = DTV_GUARD_INTERVAL,
@@ -882,6 +873,7 @@
.cmd = DTV_TRANSMISSION_MODE,
.set = 1,
},
+
/* Get */
[DTV_DISEQC_SLAVE_REPLY] = {
.name = "DTV_DISEQC_SLAVE_REPLY",
@@ -961,10 +953,15 @@
.cmd = DTV_TRANSMISSION_MODE,
.set = 0,
},
- [DTV_HIERARCHY] = {
+ [DTV_HIERARCHY] = { /* is this a hierarchical transmission - boolean*/
.name = "DTV_HIERARCHY",
.cmd = DTV_HIERARCHY,
.set = 0,
+ },
+ [DTV_ALPHA] = {
+ .name = "DTV_ALPHA",
+ .cmd = DTV_ALPHA,
+ .set = 0,
},
};
@@ -1043,14 +1040,49 @@
else
/* Including BANDWIDTH_AUTO */
c->bandwidth_hz = 0;
- c->code_rate_HP = p->u.ofdm.code_rate_HP;
- c->code_rate_LP = p->u.ofdm.code_rate_LP;
+
c->modulation = p->u.ofdm.constellation;
c->transmission_mode = p->u.ofdm.transmission_mode;
c->guard_interval = p->u.ofdm.guard_interval;
- c->hierarchy = p->u.ofdm.hierarchy_information;
+
+ if (p->u.ofdm.hierarchy_information== HIERARCHY_AUTO ||
+ p->u.ofdm.hierarchy_information == HIERARCHY_NONE) {
+ c->fec_inner = p->u.ofdm.code_rate_HP;
+ c->hierarchy = 0;
+ c->stream_selection = 1;
+ c->alpha = 1;
+ } else {
+
+ /* the previous channel descriptor does not
+ * really support hierarchy, that's why we can
+ * assume HP as selected here - closest to
+ * previous behaviour */
+ c->fec_inner = p->u.ofdm.code_rate_HP;
+
+ c->hierarchy = 1;
+ c->stream_selection = 1;
+ switch (p->u.ofdm.hierarchy_information) {
+ default: /* just to inhibit a compiler warning, both cases have been handled above */
+ case HIERARCHY_1:
+ c->alpha = 1;
+ break;
+ case HIERARCHY_2:
+ c->alpha = 2;
+ break;
+ case HIERARCHY_4:
+ c->alpha = 4;
+ break;
+ }
+ }
+
+ /* to report back the correct information to the user
+ * after a auto scan - not used for tuning */
+ c->code_rate_HP = p->u.ofdm.code_rate_HP;
+ c->code_rate_LP = p->u.ofdm.code_rate_LP;
+
c->delivery_system = SYS_DVBT;
break;
+
case FE_ATSC:
c->modulation = p->u.vsb.modulation;
if ((c->modulation == VSB_8) || (c->modulation == VSB_16))
@@ -1097,12 +1129,28 @@
p->u.ofdm.bandwidth = BANDWIDTH_8_MHZ;
else
p->u.ofdm.bandwidth = BANDWIDTH_AUTO;
- p->u.ofdm.code_rate_HP = c->code_rate_HP;
- p->u.ofdm.code_rate_LP = c->code_rate_LP;
+
+ p->u.ofdm.code_rate_HP = c->fec_inner;
+ p->u.ofdm.code_rate_LP = FEC_1_2; /* never used correctly by any frontend driver so far */
+ if (c->hierarchy) {
+ switch (c->alpha) {
+ default:
+ case 1:
+ p->u.ofdm.hierarchy_information = HIERARCHY_1;
+ break;
+ case 2:
+ p->u.ofdm.hierarchy_information = HIERARCHY_2;
+ break;
+ case 4:
+ p->u.ofdm.hierarchy_information = HIERARCHY_4;
+ break;
+ }
+ } else
+ p->u.ofdm.hierarchy_information = HIERARCHY_NONE;
+
p->u.ofdm.constellation = c->modulation;
p->u.ofdm.transmission_mode = c->transmission_mode;
p->u.ofdm.guard_interval = c->guard_interval;
- p->u.ofdm.hierarchy_information = c->hierarchy;
c->delivery_system = SYS_DVBT;
break;
case FE_ATSC:
@@ -1287,6 +1335,16 @@
case DTV_HIERARCHY:
tvp->u.data = fe->dtv_property_cache.hierarchy;
break;
+ case DTV_ALPHA:
+ tvp->u.data = fe->dtv_property_cache.alpha;
+ break;
+ case DTV_STREAM_SELECTION:
+ tvp->u.data = fe->dtv_property_cache.stream_selection;
+ break;
+ case DTV_TRANSMITTER_ID:
+ tvp->u.data = fe->dtv_property_cache.transmitter_id;
+ break;
+
default:
r = -1;
}
@@ -1376,21 +1434,20 @@
r = dvb_frontend_ioctl_legacy(inode, file, FE_SET_TONE,
(void *)fe->dtv_property_cache.sectone);
break;
- case DTV_CODE_RATE_HP:
- fe->dtv_property_cache.code_rate_HP = tvp->u.data;
- break;
- case DTV_CODE_RATE_LP:
- fe->dtv_property_cache.code_rate_LP = tvp->u.data;
- break;
case DTV_GUARD_INTERVAL:
fe->dtv_property_cache.guard_interval = tvp->u.data;
break;
case DTV_TRANSMISSION_MODE:
fe->dtv_property_cache.transmission_mode = tvp->u.data;
break;
- case DTV_HIERARCHY:
- fe->dtv_property_cache.hierarchy = tvp->u.data;
+
+ case DTV_ALPHA:
+ fe->dtv_property_cache.alpha = tvp->u.data;
break;
+ case DTV_STREAM_SELECTION:
+ fe->dtv_property_cache.stream_selection = tvp->u.data;
+ break;
+
default:
r = -1;
}
diff -r e2a8b9b9c294 linux/drivers/media/dvb/dvb-core/dvb_frontend.h
--- a/linux/drivers/media/dvb/dvb-core/dvb_frontend.h Fri Oct 17 19:45:55 2008 +0300
+++ b/linux/drivers/media/dvb/dvb-core/dvb_frontend.h Sun Oct 19 18:42:53 2008 +0200
@@ -200,7 +200,9 @@
fe_transmit_mode_t transmission_mode;
u32 bandwidth_hz; /* 0 = AUTO */
fe_guard_interval_t guard_interval;
- fe_hierarchy_t hierarchy;
+ u8 hierarchy;
+ u8 alpha;
+ u8 stream_selection;
u32 symbol_rate;
fe_code_rate_t code_rate_HP;
fe_code_rate_t code_rate_LP;
@@ -209,6 +211,8 @@
fe_rolloff_t rolloff;
fe_delivery_system_t delivery_system;
+
+ u32 transmitter_id;
#if 0
/* ISDB-T specifics */
u32 isdb_segment_idx;
diff -r e2a8b9b9c294 linux/include/linux/dvb/frontend.h
--- a/linux/include/linux/dvb/frontend.h Fri Oct 17 19:45:55 2008 +0300
+++ b/linux/include/linux/dvb/frontend.h Sun Oct 19 18:42:54 2008 +0200
@@ -300,12 +300,29 @@
#define DTV_ISDB_LAYERC_TIME_INTERLEAVING 34
#endif
#define DTV_API_VERSION 35
-#define DTV_API_VERSION 35
+
+/* FEC code rate for the two streams coded (ro), in case of no hierarchy: CODE_RATE_HP is the one */
#define DTV_CODE_RATE_HP 36
#define DTV_CODE_RATE_LP 37
+
+/* all OFDM standard have that (rw) */
#define DTV_GUARD_INTERVAL 38
+/* FFT size (rw) */
#define DTV_TRANSMISSION_MODE 39
+
+/* DVB-T hierarchical stream information and selection */
+/* hierarchical transmission in DVB-T is in fact two independent transport streams
+ * one low-priority stream and a high priority one - see code_rate above (ro) */
#define DTV_HIERARCHY 40
+/* alpha is signalled by TPS, for HIERARCHY = 0, ALPHA is 1 */
+#define DTV_ALPHA 41
+
+/* 1 = HP (default) , 0 = LP */
+#define DTV_STREAM_SELECTION 42
+/* use DTV_INNER_FEC to to tune with the DTV_STREAM_SELECTION correctly set */
+
+/* tps cell id in DVB-T - (ro) */
+#define DTV_TRANSMITTER_ID 43
#define DTV_MAX_COMMAND DTV_HIERARCHY
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