aboutsummaryrefslogtreecommitdiffstats
path: root/calc-gtf-cvt.cpp
diff options
context:
space:
mode:
authorHans Verkuil <hverkuil-cisco@xs4all.nl>2020-11-28 09:38:52 +0100
committerHans Verkuil <hverkuil-cisco@xs4all.nl>2021-02-15 13:25:51 +0100
commitaf996e6391676750d8d37b1ff7690f0936e54b3d (patch)
tree7e16bae06ef6685edae375411fb803e9ed876db2 /calc-gtf-cvt.cpp
parent7b02132df3e9fb0d947e7097a2f99973662cfe44 (diff)
edid-decode: show or calculate timings
Add new options to show all Established Timings, DMTs, VICs and HDMI VICs. Add new options to show the timings for specific Standard Timing codes, or DMT, VIC and HDMI VIC codes. Add new options to calculate GTF and CVT timings, fully implementing the GTF and CVT standards, including interlaced, overscan, reduced blanking and support for the GTF Secondary Curve. Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Diffstat (limited to 'calc-gtf-cvt.cpp')
-rw-r--r--calc-gtf-cvt.cpp238
1 files changed, 238 insertions, 0 deletions
diff --git a/calc-gtf-cvt.cpp b/calc-gtf-cvt.cpp
new file mode 100644
index 0000000..b9d62b2
--- /dev/null
+++ b/calc-gtf-cvt.cpp
@@ -0,0 +1,238 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright 2006-2012 Red Hat, Inc.
+ * Copyright 2018-2021 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ *
+ * Author: Adam Jackson <ajax@nwnk.net>
+ * Maintainer: Hans Verkuil <hverkuil-cisco@xs4all.nl>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <time.h>
+
+#include "edid-decode.h"
+
+#define CELL_GRAN 8.0
+#define MARGIN_PERC 1.8
+#define GTF_MIN_PORCH 1.0
+#define GTF_V_SYNC_RQD 3.0
+#define GTF_H_SYNC_PERC 8.0
+#define GTF_MIN_VSYNC_BP 550.0
+
+timings edid_state::calc_gtf_mode(unsigned h_pixels, unsigned v_lines,
+ double ip_freq_rqd, bool int_rqd,
+ enum gtf_ip_parm ip_parm, bool margins_rqd,
+ bool secondary, double C, double M, double K, double J)
+{
+ timings t = {};
+ /* C' and M' are part of the Blanking Duty Cycle computation */
+ double C_PRIME = ((C - J) * K / 256.0) + J;
+ double M_PRIME = K / 256.0 * M;
+
+ double h_pixels_rnd = round(h_pixels / CELL_GRAN) * CELL_GRAN;
+ double v_lines_rnd = int_rqd ? round(v_lines / 2.0) : v_lines;
+ unsigned hor_margin = margins_rqd ?
+ round(h_pixels_rnd * MARGIN_PERC / 100.0 / CELL_GRAN) * CELL_GRAN : 0;
+ unsigned vert_margin = margins_rqd ? round(MARGIN_PERC / 100.0 * v_lines_rnd) : 0;
+ double interlace = int_rqd ? 0.5 : 0;
+ double total_active_pixels = h_pixels_rnd + hor_margin * 2;
+
+ t.hact = h_pixels_rnd;
+ t.vact = v_lines;
+ t.interlaced = int_rqd;
+
+ double pixel_freq;
+ double h_blank_pixels;
+ double total_pixels;
+ double v_sync_bp;
+
+ if (ip_parm == gtf_ip_vert_freq) {
+ // vertical frame frequency (Hz)
+ double v_field_rate_rqd = int_rqd ? ip_freq_rqd * 2 : ip_freq_rqd;
+ double h_period_est = ((1.0 / v_field_rate_rqd) - GTF_MIN_VSYNC_BP / 1000000.0) /
+ (v_lines_rnd + vert_margin * 2 + GTF_MIN_PORCH + interlace) * 1000000.0;
+ v_sync_bp = round(GTF_MIN_VSYNC_BP / h_period_est);
+ double total_v_lines = v_lines_rnd + vert_margin * 2 +
+ v_sync_bp + interlace + GTF_MIN_PORCH;
+ double v_field_rate_est = 1.0 / h_period_est / total_v_lines * 1000000.0;
+ double h_period = h_period_est / (v_field_rate_rqd / v_field_rate_est);
+ double ideal_duty_cycle = C_PRIME - (M_PRIME * h_period / 1000.0);
+ h_blank_pixels = round(total_active_pixels * ideal_duty_cycle /
+ (100.0 - ideal_duty_cycle) /
+ (2 * CELL_GRAN)) * 2 * CELL_GRAN;
+ total_pixels = total_active_pixels + h_blank_pixels;
+ pixel_freq = total_pixels / h_period;
+ } else if (ip_parm == gtf_ip_hor_freq) {
+ // horizontal frequency (kHz)
+ double h_freq = ip_freq_rqd;
+ v_sync_bp = round(GTF_MIN_VSYNC_BP * h_freq / 1000.0);
+ double ideal_duty_cycle = C_PRIME - (M_PRIME / h_freq);
+ h_blank_pixels = round(total_active_pixels * ideal_duty_cycle /
+ (100.0 - ideal_duty_cycle) /
+ (2 * CELL_GRAN)) * 2 * CELL_GRAN;
+ total_pixels = total_active_pixels + h_blank_pixels;
+ pixel_freq = total_pixels * h_freq / 1000.0;
+ } else {
+ // pixel clock rate (MHz)
+ pixel_freq = ip_freq_rqd;
+ double ideal_h_period =
+ ((C_PRIME - 100.0) +
+ sqrt(((100.0 - C_PRIME) * (100.0 - C_PRIME) +
+ (0.4 * M_PRIME * (total_active_pixels + hor_margin * 2) /
+ pixel_freq)))) / 2.0 / M_PRIME * 1000.0;
+ double ideal_duty_cycle = C_PRIME - (M_PRIME * ideal_h_period) / 1000.0;
+ h_blank_pixels = round(total_active_pixels * ideal_duty_cycle /
+ (100.0 - ideal_duty_cycle) /
+ (2 * CELL_GRAN)) * 2 * CELL_GRAN;
+ total_pixels = total_active_pixels + h_blank_pixels;
+ double h_freq = pixel_freq / total_pixels * 1000.0;
+ v_sync_bp = round(GTF_MIN_VSYNC_BP * h_freq / 1000.0);
+ }
+
+ double v_back_porch = v_sync_bp - GTF_V_SYNC_RQD;
+
+ t.vbp = v_back_porch;
+ t.vsync = GTF_V_SYNC_RQD;
+ t.vfp = GTF_MIN_PORCH;
+ t.pixclk_khz = round(1000.0 * pixel_freq);
+ t.hsync = round(GTF_H_SYNC_PERC / 100.0 * total_pixels / CELL_GRAN) * CELL_GRAN;
+ t.hfp = (h_blank_pixels / 2.0) - t.hsync;
+ t.hbp = t.hfp + t.hsync;
+ t.hborder = hor_margin;
+ t.vborder = vert_margin;
+ t.pos_pol_hsync = secondary;
+ t.pos_pol_vsync = !secondary;
+ t.rb = secondary ? RB_GTF : 0;
+ return t;
+}
+
+void edid_state::edid_gtf_mode(unsigned refresh, struct timings &t)
+{
+ unsigned hratio = t.hratio;
+ unsigned vratio = t.vratio;
+ t = calc_gtf_mode(t.hact, t.vact, refresh, t.interlaced);
+ t.hratio = hratio;
+ t.vratio = vratio;
+}
+
+#define CVT_MIN_VSYNC_BP 550.0
+#define CVT_MIN_V_PORCH 3
+#define CVT_MIN_V_BPORCH 6
+#define CVT_C_PRIME 30.0
+#define CVT_M_PRIME 300.0
+#define CVT_RB_MIN_VBLANK 460.0
+
+// If rb == RB_CVT_V2, then alt means video-optimized (i.e. 59.94 instead of 60 Hz, etc.).
+// If rb == RB_CVT_V3, then alt means that rb_h_blank is 160 instead of 80.
+// Note: for RB_CVT_V3 this calculation is slightly different, but
+// since CVT 1.3 is not yet public, I cannot update the calculation yet. For now
+// it will follow V2. So RBv3 timings will be off for now.
+timings edid_state::calc_cvt_mode(unsigned h_pixels, unsigned v_lines,
+ double ip_freq_rqd, unsigned rb, bool int_rqd,
+ bool margins_rqd, bool alt)
+{
+ timings t = {};
+
+ t.hact = h_pixels;
+ t.vact = v_lines;
+ t.interlaced = int_rqd;
+
+ double cell_gran = rb == RB_CVT_V2 ? 1 : CELL_GRAN;
+ double h_pixels_rnd = floor(h_pixels / cell_gran) * cell_gran;
+ double v_lines_rnd = int_rqd ? floor(v_lines / 2.0) : v_lines;
+ unsigned hor_margin = margins_rqd ?
+ floor((h_pixels_rnd * MARGIN_PERC / 100.0) / cell_gran) * cell_gran : 0;
+ unsigned vert_margin = margins_rqd ? floor(MARGIN_PERC / 100.0 * v_lines_rnd) : 0;
+ double interlace = int_rqd ? 0.5 : 0;
+ double total_active_pixels = h_pixels_rnd + hor_margin * 2;
+ double v_field_rate_rqd = int_rqd ? ip_freq_rqd * 2 : ip_freq_rqd;
+ double clock_step = rb == RB_CVT_V2 ? 0.001 : 0.25;
+ double h_blank = (rb == RB_CVT_V1 || (rb == RB_CVT_V3 && alt)) ? 160 : 80;
+ double rb_v_fporch = rb == RB_CVT_V1 ? 3 : 1;
+ double refresh_multiplier = (rb == RB_CVT_V2 && alt) ? 1000.0 / 1001.0 : 1;
+ double h_sync = 32;
+
+ double v_sync;
+ double pixel_freq;
+ double v_blank;
+ double v_sync_bp;
+
+ /* Determine VSync Width from aspect ratio */
+ if ((t.vact * 4 / 3) == t.hact)
+ v_sync = 4;
+ else if ((t.vact * 16 / 9) == t.hact)
+ v_sync = 5;
+ else if ((t.vact * 16 / 10) == t.hact)
+ v_sync = 6;
+ else if (!(t.vact % 4) && ((t.vact * 5 / 4) == t.hact))
+ v_sync = 7;
+ else if ((t.vact * 15 / 9) == t.hact)
+ v_sync = 7;
+ else /* Custom */
+ v_sync = 10;
+
+ if (rb >= RB_CVT_V2)
+ v_sync = 8;
+
+ if (rb == 0) {
+ double h_period_est = ((1.0 / v_field_rate_rqd) - CVT_MIN_VSYNC_BP / 1000000.0) /
+ (v_lines_rnd + vert_margin * 2 + CVT_MIN_V_PORCH + interlace) * 1000000.0;
+ v_sync_bp = floor(CVT_MIN_VSYNC_BP / h_period_est) + 1;
+ if (v_sync_bp < v_sync + CVT_MIN_V_BPORCH)
+ v_sync_bp = v_sync + CVT_MIN_V_BPORCH;
+ v_blank = v_sync_bp + CVT_MIN_V_PORCH;
+ double ideal_duty_cycle = CVT_C_PRIME - (CVT_M_PRIME * h_period_est / 1000.0);
+ if (ideal_duty_cycle < 20)
+ ideal_duty_cycle = 20;
+ h_blank = floor(total_active_pixels * ideal_duty_cycle /
+ (100.0 - ideal_duty_cycle) /
+ (2 * CELL_GRAN)) * 2 * CELL_GRAN;
+ double total_pixels = total_active_pixels + h_blank;
+ h_sync = floor(total_pixels * 0.08 / CELL_GRAN) * CELL_GRAN;
+ pixel_freq = floor((total_pixels / h_period_est) / clock_step) * clock_step;
+ } else {
+ double h_period_est = ((1000000.0 / v_field_rate_rqd) - CVT_RB_MIN_VBLANK) /
+ (v_lines_rnd + vert_margin * 2);
+ double vbi_lines = floor(CVT_RB_MIN_VBLANK / h_period_est) + 1;
+ double rb_min_vbi = rb_v_fporch + v_sync + CVT_MIN_V_BPORCH;
+ v_blank = vbi_lines < rb_min_vbi ? rb_min_vbi : vbi_lines;
+ double total_v_lines = v_blank + v_lines_rnd + vert_margin * 2 + interlace;
+ if (rb == RB_CVT_V1)
+ v_sync_bp = v_blank - rb_v_fporch;
+ else
+ v_sync_bp = v_sync + CVT_MIN_V_BPORCH;
+ double total_pixels = h_blank + total_active_pixels;
+ pixel_freq = floor((v_field_rate_rqd * total_v_lines * total_pixels / 1000000.0 *
+ refresh_multiplier) / clock_step) * clock_step;
+ }
+
+ t.vbp = v_sync_bp - v_sync;
+ t.vsync = v_sync;
+ t.vfp = v_blank - t.vbp - t.vsync;
+ t.pixclk_khz = round(1000.0 * pixel_freq);
+ t.hsync = h_sync;
+ t.hfp = (h_blank / 2.0) - t.hsync;
+ t.hbp = t.hfp + t.hsync;
+ t.hborder = hor_margin;
+ t.vborder = vert_margin;
+ t.rb = rb;
+ if (alt && (rb == RB_CVT_V2 || rb == RB_CVT_V3))
+ t.rb |= RB_FLAG;
+ t.pos_pol_hsync = t.rb;
+ t.pos_pol_vsync = !t.rb;
+ calc_ratio(&t);
+ return t;
+}
+
+void edid_state::edid_cvt_mode(unsigned refresh, struct timings &t)
+{
+ unsigned hratio = t.hratio;
+ unsigned vratio = t.vratio;
+
+ t = calc_cvt_mode(t.hact, t.vact, refresh, t.rb & ~RB_FLAG, t.interlaced,
+ false, t.rb & RB_FLAG);
+ t.hratio = hratio;
+ t.vratio = vratio;
+}

Privacy Policy