func (d Device) Guard() (dvb.Guard, error) {
g, e := d.get(dtvGuardInterval)
if e != 0 {
return 0, Error{"get", "guard interval", e}
}
return dvb.Guard(g), nil
}
func ParseTerrestrialDeliverySystemDescriptor(d Descriptor) (tds TerrestrialDeliverySystemDescriptor, ok bool) {
if d.Tag() != TerrestrialDeliverySystemTag {
return
}
data := d.Data()
if len(data) < 11 {
return
}
tds.Freq = int64(decodeU32(data[0:4])) * 10
switch data[4] >> 5 {
case 0:
tds.Bandwidth = 8e6
case 1:
tds.Bandwidth = 7e6
case 2:
tds.Bandwidth = 6e6
case 3:
tds.Bandwidth = 5e6
default:
return
}
tds.HighPrio = data[4]&0x10 != 0
tds.TimeSlicing = data[4]&0x08 == 0
tds.MPEFEC = data[4]&0x04 == 0
switch data[5] >> 6 {
case 0:
tds.Constellation = dvb.QPSK
case 1:
tds.Constellation = dvb.QAM16
case 2:
tds.Constellation = dvb.QAM64
default:
return
}
tds.Hierarchy = dvb.Hierarchy((data[5] >> 3) & 0x07)
if tds.Hierarchy > dvb.Hierarchy4 {
return
}
tds.CodeRateHP = decodeCodeRate(data[5] & 0x07)
if tds.CodeRateHP == dvb.FECAuto || tds.CodeRateHP == dvb.FECNone {
return
}
tds.CodeRateLP = decodeCodeRate(data[6] >> 5)
if tds.CodeRateLP == dvb.FECAuto {
return
}
tds.Guard = dvb.Guard((data[6] >> 3) & 0x03)
tds.TxMode = dvb.TxMode((data[6] >> 1) & 0x03)
if tds.TxMode > dvb.TxMode8k {
return
}
tds.OtherFreq = data[6]&0x01 != 0
ok = true
return
}