On Wed October 17 2012 02:25:00 Laurent Pinchart wrote: > Hi Hans, > > On Monday 15 October 2012 13:35:45 Hans Verkuil wrote: > > During the Plumbers Conference a few weeks ago we had a session to resolve > > V4L2 ambiguities. It was very successful, but we didn't manage to tackle > > two of the harder topics, and a third one (timestamps) cause a lot of > > discussion on the mailinglist after the conference. > > > > So here is the list I have today. Any other ambiguities or new features that > > should be added to the list? > > Small topic that we've briefly discussed on IRC: if a device doesn't tell the > driver what color space it uses, should the driver guess or tell the > application that the color space is unknown ? I've ran into that issue for the > uvcvideo driver, while I agree with you that in that case the color space is > very likely sRGB, and that the driver is probably in a better position to make > that guess than the userspace application (as the driver knows it handles a > webcam), what should be the rule ? I'll add it to the list. > > 1) Make a decision how to tell userspace that the monotonic timestamp is > > used. > > > > Several proposals were made, but no decision was taken AFAIK. Can someone > > (Sakari?) make a summary/current status of this? > > > > > > 2) Pixel Aspect Ratio > > > > Pixel aspect: currently this is only available through VIDIOC_CROPCAP. It > > never really belonged to VIDIOC_CROPCAP IMHO. It's just not a property of > > cropping or composing. It really belongs to the input/output timings (STD > > or DV_TIMINGS). That's where the pixel aspect ratio is determined. > > > > While it is possible to add it to the dv_timings struct, I see no way of > > cleanly adding it to struct v4l2_standard (mostly because VIDIOC_ENUMSTD is > > now handled inside the V4L2 core and doesn't call the drivers anymore). > > Isn't that an implementation issue instead of an API issue ? True, but it will require changing all drivers. But adding it to v4l2_standard would be the best place for this, so perhaps we should think about doing all this work. Regards, Hans -- 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
