[Intel-gfx] [PATCH] Implement Limited Video Range
Ville Syrjälä
ville.syrjala at linux.intel.com
Wed Nov 9 20:25:48 UTC 2016
On Wed, Nov 09, 2016 at 09:11:58PM +0100, Peter Frühberger wrote:
> I am currently not sure what the way forward should be.
>
> We are successfully implementing this patch in e.g. LibreELEC an embedded
> distribution for home theater pcs. But through current bug reports - I am
> not sure, if we should give such functionality to the user, that is
> overwritten on a lower level, e.g. it does not what the user expects.
>
> E.g. since some time displays are driven with 10 or 12 bit from the intel
> driver, image data is dithered, scaled back and forth without being
> transparent for the user. In fact we have some users with hdmi capture
> cards, coming back to us if some decoded values of their video stuff does
> not match.
Re-reading what was written (can't remember anymore obviously), I think
what both me and Daniel were after was a cleaner separation of the
"what should the infoframe say?" and "how should we mangle the color data?".
Daniel's "limit_color_range" is a wee bit too similar looking to
"limited_color_range" for my liking. So how about we go with something
like "bool compress_color_range". It also conveys the fact that we're
not just clamping things. Any objections/thoughts/better ideas?
>
> Best regards
> Peter
>
> On Mon, Nov 30, 2015 at 3:11 PM, Ville Syrjälä <
> ville.syrjala at linux.intel.com> wrote:
>
> > On Mon, Nov 30, 2015 at 09:43:32AM +0100, Daniel Vetter wrote:
> > > On Mon, Nov 30, 2015 at 08:08:48AM +0100, Peter Frühberger wrote:
> > > > (Resent cause of moderation)
> > > >
> > > > This implements a highly needed feature in a minimal non instructive
> > way.
> > > > Consider a Limited Range display (like most TVs) where you want to
> > watch a
> > > > decoded video. The TV is set to limited range and the intel driver also
> > > > uses full scaling Limited 16:235 mode, e.g. if you display the gray
> > value
> > > > 16 - the driver will postprocess it to something like ~ 22.
> > > >
> > > > The following happens currently in linux intel video world:
> > > > Video is decoded with e.g. vaapi, the decoded surface is either used
> > via
> > > > EGL directly in Limited Range. Limited Range processing takes place
> > and at
> > > > the end while rendering the intel driver will scale down the limited
> > range
> > > > data again as it cannot distunguish of the data it gets when e.g.
> > rendering
> > > > with OpenGL like we succesfully do in kodi.
> > > >
> > > > Another use case is vaapi when using the old vaCopySurfaceGLX
> > > > (vaPutSurface) which would automatically use BT601 / BT709 matrix to
> > > > upscale the content without any dithering to Full Range RGB. Later on
> > this
> > > > is scaled down again with the Limited 16:235 setting and output.
> > Quality
> > > > degrades two times.
> > > >
> > > > Users and applications widely used want to make sure that colors
> > appear on
> > > > screen like they were processed after the last processing step. In
> > video
> > > > case two use cases make sense:
> > > >
> > > > a) scaling limited range to full range with dithering applied when you
> > need
> > > > to output fullrange
> > > > b) already having limited range and outputting that without any further
> > > > touching by the driver
> > > >
> > > > Use case a) is already possible. Usecase b) will be possible with the
> > > > attached patch. It is a possibility to get Limited Range on screen in
> > > > perfect quality in 2k15.
> > > >
> > > > For the future a userspace api to provide info frames and so on in a
> > > > generic way should be considered but until we have this I bet we have 2
> > > > years to go. This solution also works on X11 (without wayland) and is
> > > > useful for existing applications.
> > > >
> > > > Thanks much for consideration.
> > > >
> > > > ---
> > > > From deaa9d730c08aefefe3671d073d93d970bb39a31 Mon Sep 17 00:00:00 2001
> > > > From: fritsch <peter.fruehberger at gmail.com>
> > > > Date: Sun, 29 Nov 2015 16:38:14 +0100
> > > > Subject: [PATCH] Intel: Implement Video Color Range
> > > >
> > > > ---
> > > > drivers/gpu/drm/i915/i915_drv.h | 1 +
> > > > drivers/gpu/drm/i915/intel_display.c | 4 ++--
> > > > drivers/gpu/drm/i915/intel_drv.h | 8 ++++++++
> > > > drivers/gpu/drm/i915/intel_hdmi.c | 17 +++++++++++++++--
> > > > drivers/gpu/drm/i915/intel_modes.c | 1 +
> > > > 5 files changed, 27 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/i915/i915_drv.h
> > > > b/drivers/gpu/drm/i915/i915_drv.h
> > > > index 95bb27d..e453461 100644
> > > > --- a/drivers/gpu/drm/i915/i915_drv.h
> > > > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > > > @@ -3449,6 +3449,7 @@ int intel_freq_opcode(struct drm_i915_private
> > > > *dev_priv, int val);
> > > > #define INTEL_BROADCAST_RGB_AUTO 0
> > > > #define INTEL_BROADCAST_RGB_FULL 1
> > > > #define INTEL_BROADCAST_RGB_LIMITED 2
> > > > +#define INTEL_BROADCAST_RGB_VIDEO 3
> > > >
> > > > static inline uint32_t i915_vgacntrl_reg(struct drm_device *dev)
> > > > {
> > > > diff --git a/drivers/gpu/drm/i915/intel_display.c
> > > > b/drivers/gpu/drm/i915/intel_display.c
> > > > index 71860f8..ea40d81 100644
> > > > --- a/drivers/gpu/drm/i915/intel_display.c
> > > > +++ b/drivers/gpu/drm/i915/intel_display.c
> > > > @@ -8605,7 +8605,7 @@ static void intel_set_pipe_csc(struct drm_crtc
> > *crtc)
> > > > * consideration.
> > > > */
> > > >
> > > > - if (intel_crtc->config->limited_color_range)
> > > > + if (intel_crtc->config->limited_color_range &&
> > > > !intel_crtc->config->video_color_range)
> > > > coeff = ((235 - 16) * (1 << 12) / 255) & 0xff8; /* 0.xxx... */
> > > >
> > > > /*
> > > > @@ -8629,7 +8629,7 @@ static void intel_set_pipe_csc(struct drm_crtc
> > *crtc)
> > > > if (INTEL_INFO(dev)->gen > 6) {
> > > > uint16_t postoff = 0;
> > > >
> > > > - if (intel_crtc->config->limited_color_range)
> > > > + if (intel_crtc->config->limited_color_range &&
> > > > !intel_crtc->config->video_color_range)
> > > > postoff = (16 * (1 << 12) / 255) & 0x1fff;
> > > >
> > > > I915_WRITE(PIPE_CSC_POSTOFF_HI(pipe), postoff);
> > > > diff --git a/drivers/gpu/drm/i915/intel_drv.h
> > > > b/drivers/gpu/drm/i915/intel_drv.h
> > > > index 0598932..6940243 100644
> > > > --- a/drivers/gpu/drm/i915/intel_drv.h
> > > > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > > > @@ -372,6 +372,13 @@ struct intel_crtc_state {
> > > > */
> > > > bool limited_color_range;
> > > >
> > > > + /*
> > > > + *
> > > > + * Use reduced/limited/broadcast rgb range without compressing.
> > > > + *
> > > > + */
> > > > + bool video_color_range;
> > >
> > > I think the names and semantics are confusion, resulting in hard-to-read
> > > if conditions. What about:
> > >
> > > bool limit_color_range; /* should we limit from full->16:235 in
> > > the encoder/csc? */
> >
> > We might call this simply as "adjust_color_range" or something like
> > that. Then it would also work for the limited->full conversion if we
> > ever come up with some use case that would need such a thing. Althoguh
> > it does mean we'd have to check both flags when deciding how to program
> > the port/pipeconf range bit/pipe csc.
> >
> > >
> > > bool limited_color_range_output; /* set the infoframe or not? */
> > >
> > > Names aren't great yet I think, coffee's not yet working ;-)
> > >
> > > Thanks, Daniel
> > >
> > > > +
> > > > /* DP has a bunch of special case unfortunately, so mark the pipe
> > > > * accordingly. */
> > > > bool has_dp_encoder;
> > > > @@ -682,6 +689,7 @@ struct intel_hdmi {
> > > > int ddc_bus;
> > > > bool limited_color_range;
> > > > bool color_range_auto;
> > > > + bool color_range_video;
> > > > bool has_hdmi_sink;
> > > > bool has_audio;
> > > > enum hdmi_force_audio force_audio;
> > > > diff --git a/drivers/gpu/drm/i915/intel_hdmi.c
> > > > b/drivers/gpu/drm/i915/intel_hdmi.c
> > > > index 9eafa19..dc78760 100644
> > > > --- a/drivers/gpu/drm/i915/intel_hdmi.c
> > > > +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> > > > @@ -464,7 +464,8 @@ static void intel_hdmi_set_avi_infoframe(struct
> > > > drm_encoder *encoder,
> > > > }
> > > >
> > > > if (intel_hdmi->rgb_quant_range_selectable) {
> > > > - if (intel_crtc->config->limited_color_range)
> > > > + if (intel_crtc->config->limited_color_range ||
> > > > + intel_crtc->config->video_color_range)
> > > > frame.avi.quantization_range =
> > > > HDMI_QUANTIZATION_RANGE_LIMITED;
> > > > else
> > > > @@ -1266,6 +1267,8 @@ bool intel_hdmi_compute_config(struct
> > intel_encoder
> > > > *encoder,
> > > > pipe_config->limited_color_range =
> > > > intel_hdmi->limited_color_range;
> > > > }
> > > > + if (intel_hdmi->color_range_video)
> > > > + pipe_config->video_color_range = true;
> > > >
> > > > if (adjusted_mode->flags & DRM_MODE_FLAG_DBLCLK) {
> > > > pipe_config->pixel_multiplier = 2;
> > > > @@ -1485,25 +1488,35 @@ intel_hdmi_set_property(struct drm_connector
> > > > *connector,
> > > > if (property == dev_priv->broadcast_rgb_property) {
> > > > bool old_auto = intel_hdmi->color_range_auto;
> > > > bool old_range = intel_hdmi->limited_color_range;
> > > > + bool old_range_video = intel_hdmi->color_range_video;
> > > >
> > > > switch (val) {
> > > > case INTEL_BROADCAST_RGB_AUTO:
> > > > intel_hdmi->color_range_auto = true;
> > > > + intel_hdmi->color_range_video = false;
> > > > break;
> > > > case INTEL_BROADCAST_RGB_FULL:
> > > > intel_hdmi->color_range_auto = false;
> > > > intel_hdmi->limited_color_range = false;
> > > > + intel_hdmi->color_range_video = false;
> > > > break;
> > > > case INTEL_BROADCAST_RGB_LIMITED:
> > > > intel_hdmi->color_range_auto = false;
> > > > intel_hdmi->limited_color_range = true;
> > > > + intel_hdmi->color_range_video = false;
> > > > + break;
> > > > + case INTEL_BROADCAST_RGB_VIDEO:
> > > > + intel_hdmi->color_range_auto = false;
> > > > + intel_hdmi->limited_color_range = true;
> > > > + intel_hdmi->color_range_video = true;
> > > > break;
> > > > default:
> > > > return -EINVAL;
> > > > }
> > > >
> > > > if (old_auto == intel_hdmi->color_range_auto &&
> > > > - old_range == intel_hdmi->limited_color_range)
> > > > + old_range == intel_hdmi->limited_color_range &&
> > > > + old_range_video == intel_hdmi->color_range_video)
> > > > return 0;
> > > >
> > > > goto done;
> > > > diff --git a/drivers/gpu/drm/i915/intel_modes.c
> > > > b/drivers/gpu/drm/i915/intel_modes.c
> > > > index 38a4c8c..c49681a 100644
> > > > --- a/drivers/gpu/drm/i915/intel_modes.c
> > > > +++ b/drivers/gpu/drm/i915/intel_modes.c
> > > > @@ -103,6 +103,7 @@ static const struct drm_prop_enum_list
> > > > broadcast_rgb_names[] = {
> > > > { INTEL_BROADCAST_RGB_AUTO, "Automatic" },
> > > > { INTEL_BROADCAST_RGB_FULL, "Full" },
> > > > { INTEL_BROADCAST_RGB_LIMITED, "Limited 16:235" },
> > > > + { INTEL_BROADCAST_RGB_VIDEO, "Video 16:235 pass-through" },
> > > > };
> > > >
> > > > void
> > > > --
> > > > 2.5.0
> > >
> > > > _______________________________________________
> > > > Intel-gfx mailing list
> > > > Intel-gfx at lists.freedesktop.org
> > > > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > >
> > >
> > > --
> > > Daniel Vetter
> > > Software Engineer, Intel Corporation
> > > http://blog.ffwll.ch
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx at lists.freedesktop.org
> > > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >
> > --
> > Ville Syrjälä
> > Intel OTC
> >
--
Ville Syrjälä
Intel OTC
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