On Friday 23 October 2009 06:13:30 Jean Delvare wrote: > Hi folks, > > I am looking for details regarding the DVB frontend API. I've read > linux-dvb-api-1.0.0.pdf, it roughly explains what the FE_READ_BER, > FE_READ_SNR, FE_READ_SIGNAL_STRENGTH and FE_READ_UNCORRECTED_BLOCKS > commands return, however it does not give any information about how the > returned values should be interpreted (or, seen from the other end, how > the frontend kernel drivers should encode these values.) If there > documentation available that would explain this? > > For example, the signal strength. All I know so far is that this is a > 16-bit value. But then what? Do greater values represent stronger > signal or weaker signal? Are 0x0000 and 0xffff special values? Is the > returned value meaningful even when FE_HAS_SIGNAL is 0? When > FE_HAS_LOCK is 0? Is the scale linear, or do some values have > well-defined meanings, or is it arbitrary and each driver can have its > own scale? What are the typical use cases by user-space application for > this value? > > That's the kind of details I'd like to know, not only for the signal > strength, but also for the SNR, BER and UB. Without this information, > it seems a little difficult to have consistent frontend drivers. > > Thanks, I have tried on two occasions to engage the the author of my particular driver as to how to implement a patch and use femon with no response. Its good that there is some movement at last which might get a result. I've said before I don't really care too much about spot on accuracy but rather a scale that increases as you get closer to a lock. I can imagine there are loads of users out there who rely on the output of things like femon and vdr-rotor to tune their equipment and with S2 cards like both of mine they are knackered so to speak. Mike -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
