Le dimanche 03 juillet 2016 à 11:43 +0200, Hans Verkuil a écrit : > Hi Nicolas, > > On 07/02/2016 10:29 PM, Nicolas Dufresne wrote: > > > > Le 30 juin 2016 5:35 PM, "Shuah Khan" <shuahkh@xxxxxxxxxxxxxxx > > <mailto:shuahkh@xxxxxxxxxxxxxxx>> a écrit : > > > > > > Remove vidioc_g_crop() from s5p-mfc decoder. Without its s_crop > > > counterpart > > > g_crop is not useful. Delete it. > > > > G_CROP tell the userspace which portion of the output is to be > > displayed. Example, 1920x1080 inside a buffer of 1920x1088. It can > > be > > implemented using G_SELECTION too, which emulate G_CROP. removing > > this without implementing G_SEKECTION will break certain software > > like > > GStreamer v4l2 based decoder. > > Sorry, but this is not correct. > > G_CROP for VIDEO_OUTPUT returns the output *compose* rectangle, not > the output > crop rectangle. > > Don't blame me, this is how it was defined in V4L2. The problem is > that for video > output (esp. m2m devices) you usually want to set the crop rectangle, > and that's > why the selection API was added so you can unambiguously set the crop > and compose > rectangles for both capture and output. > > Unfortunately, the exynos drivers were written before the > G/S_SELECTION API was > created, and the crop ioctls in the video output drivers actually set > the output > crop rectangle instead of the compose rectangle :-( > > This is a known inconsistency. > > You are right though that we can't remove g_crop here, I had > forgotten about the > buffer padding. > > What should happen here is that g_selection support is added to s5p- > mfc, and > have that return the proper rectangles. The g_crop can be kept, and a > comment > should be added that it returns the wrong thing, but that that is > needed for > backwards compat. > > The gstreamer code should use g/s_selection if available. It should > check how it > is using g/s_crop for video output devices today and remember that > for output > devices g/s_crop is really g/s_compose, except for the exynos > drivers. This is already the case. There is other non-mainline driver that do like exynos (I have been told). https://cgit.freedesktop.org/gstreamer/gst-plugins-good/commit/sys?id=7 4f020fd2f1dc645efe35a7ba1f951f9c5ee7c4c > > It's why I recommend the selection API since it doesn't have these > problems. > > I think I should do another push towards implementing the selection > API in all > drivers. There aren't many left. > > 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
