On 08/08/2011 19:06, Nima Mohammadi wrote: > Hi folks, > I was reading the source code of various dvb related utilities and I > was wondering about forming up the message which instructs the DiSEqC > switch. But I found out that different programs produce the command > differently. > The confusing thing is that according to the DiSEqC specification > documents that I've read, the least significant bit (lsb) must > indicate the band (low/high), not the polarity (ver/hor), but as you > see it only applies to some of these programs: > > getstrean abd dvbstream: > int i = 4 * switch_pos + 2 * hiband + (voltage_18 ? 1 : 0); > > szap and mplayer: > (((sat_no * 4) & 0x0f) | (hi_lo ? 1 : 0) | (polv ? 0 : 2)); > > scan: > 4 * switch_pos + 2 * hiband + (voltage_18 ? 1 : 0) > > gstdvbsrc: > (((sat_no * 4) & 0x0f) | (tone == SEC_TONE_ON ? 1 : 0) | (voltage == > SEC_VOLTAGE_13 ? 0 : 2)); > > Hello I'm the upstream author of MuMuDVB (http://mumudvb.braice.net) The diseqc related code is here http://gitweb.braice.net/gitweb?p=mumudvb;a=blob;f=src/tune.c On the document http://www.eutelsat.com/satellites/pdf/Diseqc/associated%20docs/applic_info_LNB_switchers.pdf Page 7 (page 10 of the PDF) the band is the LSB and the table is organized in increasing binary data But in http://www.eutelsat.com/satellites/pdf/Diseqc/associated%20docs/update_recomm_for_implim.pdf page 33 (35 in the PDF) The LSB SEEMS to be the polarization, but it's still the band, the table is just organized in a strange way If you look deeply into the code of scan http://www.linuxtv.org/hg/dvb-apps/file/36a084aace47/util/scan/diseqc.c You'll see that the table is organized as in the second document and the code addresses the table for making the message but there is no mistake in the real data since it's f0,f2,f1 etc ... So the difference is if the diseqc data is wrote directly (as in MuMuDVB) or taken from a table organised as in the specification (as in scan) Hope it's clear and it helps Regards -- Brice A: Yes. >Q: Are you sure? >>A: Because it reverses the logical flow of conversation. >>>Q: Why is top posting annoying in email? -- 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
