Andreas Oberritter wrote:
> On Tue, 2005-07-26 at 11:23 +0200, Johannes Stezenbach wrote:
> > Andreas Oberritter wrote:
> > > if you have multiple displays and/or Picture-In-Picture decoding, then
> > > you have to define one PCR per display as master for vcxo control.
> > >
> > > Therefore I propose the following simple interface:
> > >
> > > struct dmx_stc_mapping {
> > > unsigned int clock_num;
> > > unsigned int pcr_num;
> > > }
> > >
> > > #define DMX_SET_STC_MAPPING _IOWR('o', 51, struct dmx_stc_mapping)
> >
> > I think the naming is a bit misleading, because in your first
> > sentence you say that this is about setting the "master for
> > vcxo control". I.e. (if I get it right) you have one 27MHz
> > crystal, but two PCR/STC. Obviously the vcxo can be synced to
> > only one of them, so you have to choose (for PiP usually the
> > one with the bigger picture).
> >
> > How about:
> >
> > struct dmx_vcxo_control {
> > unsigned int vcxo_num; // in case you have more than one vcxo
> > unsigned int pcr_num; // which PCR to sync the vcxo to
> > };
> >
> > #define DMX_VCXO_CONTROL _IOWR('o', 51, struct dmx_vcxo_control)
> >
> > or maybe DMX_SET_VCXO_SYNC_SOURCE?
>
> You are right, "stc" was quite confusing.
STC was actually not confusing, but "mapping" was.
> I've been told that using a VCXO is not the only way to synchronize the
> transmitter and receiver clock, so how about your proposal with "vcxo"
> replaced by the more generic "clock"?
Maybe we should use "STC" then. What hardware is there when
no VCXO is used?
Johannes
