On Monday, September 13, 2010 12:50:31 Matti J. Aaltonen wrote: > On Sat, 2010-09-11 at 14:10 +0200, ext Hans Verkuil wrote: > > There are also up to three ways the RDS data can be received/sent: either as > > RDS blocks, or using controls, or as a completely raw bitstream. The latter is > > unlikely to be used for RDS output, but a cheap RDS receiver might just do this > > (and I believe these devices actually exist). > > I thought that the "raw" mode meant reading and writing (uninterpreted) > RDS blocks. At least that's what the wl1273 chip does and that was what > I meant. Is there already a way to deal with this case? I had to dig into the linux-media archives, but I found one chip (the cx2388x) that produces a 38 kHz 16 bit RDS data stream that needs to be demodulated in software. That's really raw :-) But I'm not aware of any board based on this chipset that actually uses this. > Anyway the difference between the "completely raw bits" and the "raw" > blocks is small. And I doubt the usefulness of supporting the > "completely raw" format. I don't intend to support it now. But we need to realize that it exists and we have to plan for it. Regards, Hans > > B.R. > Matti > > > So I propose to add the following tuner capability flags: > > > > V4L2_TUNER_CAP_RDS_READWRITE 0x0100 Use read()/write() > > V4L2_TUNER_CAP_RDS_CONTROLS 0x0200 Use RDS controls > > > > And this allows us to add a RDS_RAW_READWRITE in the future should we need it. > > > > We do need to add these capability flags to the existing RDS drivers (there > > are only a few, so that's no problem) and we need to document that for RDS > > capture the READWRITE is the default if neither READWRITE or CONTROLS is set, > > and that for RDS output the CONTROLS is the default in that case. > > > > Comments? > > > > Hans > > > > > -- Hans Verkuil - video4linux developer - sponsored by TANDBERG, part of Cisco -- 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
