[PATCH 1/2] OMAPDSS: DISPC: Update Fir Coefficients

Chandrabhanu Mahapatra
2011-12-14T04:51:56Z

The FIR coefficients present in kernel are being updated to new coefficients
consisting of 24 coefficient tables, with 12 each for 3 tap and 5 tap scenario,
which are chosen on the basis of DISPC up/downsampling filters M value. M is
the inverse of low pass cut off frequency of the sampling filter. For vertical
scaling 3 tap or 5 tap tables are used based on the clock rate and width of
the line buffer whereas in OMAP2 3 tap is always used. For horizontal scaling
however 5 tap tables are always used.

New coefficients and the corresponding logic have been tested on OMAP2, OMAP3
and OMAP4. Horizontal and vertical scaling worked fine except for some 3 tap
vs 5 tap issue during vertical upscaling and clock failing issues which is
acknowledged in the next patch. Vertical upscaling was found to perform better
under 5 taps. The 24 coefficient tables have been moved to another file
dispc_coefs.c for proper maintainance.

This code is written based on code written by Lajos Molnar <lajos@ti.com> in
Android Kernel for scaling. Lajos Molnar <lajos@ti.com> had fine tuned the FIR
coefficient selection process and reduced outliness and blockiness around
images when upscaling more than 2 times.

Signed-off-by: Chandrabhanu Mahapatra <cmahapatra@ti.com>
---
drivers/video/omap2/dss/Makefile | 2 +-
drivers/video/omap2/dss/dispc.c | 135 ++------------
drivers/video/omap2/dss/dispc.h | 11 +
drivers/video/omap2/dss/dispc_coefs.c | 327 +++++++++++++++++++++++++++++++++
4 files changed, 357 insertions(+), 118 deletions(-)
create mode 100644 drivers/video/omap2/dss/dispc_coefs.c

diff --git a/drivers/video/omap2/dss/Makefile b/drivers/video/omap2/dss/Makefile
index bd34ac5..f10d56f 100644
--- a/drivers/video/omap2/dss/Makefile
+++ b/drivers/video/omap2/dss/Makefile
@@ -1,5 +1,5 @@
obj-$(CONFIG_OMAP2_DSS) += omapdss.o
-omapdss-y := core.o dss.o dss_features.o dispc.o display.o manager.o overlay.o
+omapdss-y := core.o dss.o dss_features.o dispc.o dispc_coefs.o display.o manager.o overlay.o
omapdss-$(CONFIG_OMAP2_DSS_DPI) += dpi.o
omapdss-$(CONFIG_OMAP2_DSS_RFBI) += rfbi.o
omapdss-$(CONFIG_OMAP2_DSS_VENC) += venc.o
diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
index 6892cfd..b981983 100644
--- a/drivers/video/omap2/dss/dispc.c
+++ b/drivers/video/omap2/dss/dispc.c
@@ -63,22 +63,6 @@ struct omap_dispc_isr_data {
u32 mask;
};

-struct dispc_h_coef {
- s8 hc4;
- s8 hc3;
- u8 hc2;
- s8 hc1;
- s8 hc0;
-};
-
-struct dispc_v_coef {
- s8 vc22;
- s8 vc2;
- u8 vc1;
- s8 vc0;
- s8 vc00;
-};
-
enum omap_burst_size {
BURST_SIZE_X2 = 0,
BURST_SIZE_X4 = 1,
@@ -532,105 +516,27 @@ static void dispc_ovl_write_firv2_reg(enum omap_plane plane, int reg, u32 value)
dispc_write_reg(DISPC_OVL_FIR_COEF_V2(plane, reg), value);
}

-static void dispc_ovl_set_scale_coef(enum omap_plane plane, int hscaleup,
- int vscaleup, int five_taps,
- enum omap_color_component color_comp)
-{
- /* Coefficients for horizontal up-sampling */
- static const struct dispc_h_coef coef_hup[8] = {
- { 0, 0, 128, 0, 0 },
- { -1, 13, 124, -8, 0 },
- { -2, 30, 112, -11, -1 },
- { -5, 51, 95, -11, -2 },
- { 0, -9, 73, 73, -9 },
- { -2, -11, 95, 51, -5 },
- { -1, -11, 112, 30, -2 },
- { 0, -8, 124, 13, -1 },
- };
-
- /* Coefficients for vertical up-sampling */
- static const struct dispc_v_coef coef_vup_3tap[8] = {
- { 0, 0, 128, 0, 0 },
- { 0, 3, 123, 2, 0 },
- { 0, 12, 111, 5, 0 },
- { 0, 32, 89, 7, 0 },
- { 0, 0, 64, 64, 0 },
- { 0, 7, 89, 32, 0 },
- { 0, 5, 111, 12, 0 },
- { 0, 2, 123, 3, 0 },
- };
-
- static const struct dispc_v_coef coef_vup_5tap[8] = {
- { 0, 0, 128, 0, 0 },
- { -1, 13, 124, -8, 0 },
- { -2, 30, 112, -11, -1 },
- { -5, 51, 95, -11, -2 },
- { 0, -9, 73, 73, -9 },
- { -2, -11, 95, 51, -5 },
- { -1, -11, 112, 30, -2 },
- { 0, -8, 124, 13, -1 },
- };
-
- /* Coefficients for horizontal down-sampling */
- static const struct dispc_h_coef coef_hdown[8] = {
- { 0, 36, 56, 36, 0 },
- { 4, 40, 55, 31, -2 },
- { 8, 44, 54, 27, -5 },
- { 12, 48, 53, 22, -7 },
- { -9, 17, 52, 51, 17 },
- { -7, 22, 53, 48, 12 },
- { -5, 27, 54, 44, 8 },
- { -2, 31, 55, 40, 4 },
- };
-
- /* Coefficients for vertical down-sampling */
- static const struct dispc_v_coef coef_vdown_3tap[8] = {
- { 0, 36, 56, 36, 0 },
- { 0, 40, 57, 31, 0 },
- { 0, 45, 56, 27, 0 },
- { 0, 50, 55, 23, 0 },
- { 0, 18, 55, 55, 0 },
- { 0, 23, 55, 50, 0 },
- { 0, 27, 56, 45, 0 },
- { 0, 31, 57, 40, 0 },
- };
-
- static const struct dispc_v_coef coef_vdown_5tap[8] = {
- { 0, 36, 56, 36, 0 },
- { 4, 40, 55, 31, -2 },
- { 8, 44, 54, 27, -5 },
- { 12, 48, 53, 22, -7 },
- { -9, 17, 52, 51, 17 },
- { -7, 22, 53, 48, 12 },
- { -5, 27, 54, 44, 8 },
- { -2, 31, 55, 40, 4 },
- };
-
- const struct dispc_h_coef *h_coef;
- const struct dispc_v_coef *v_coef;
+static void dispc_ovl_set_scale_coef(enum omap_plane plane, int fir_hinc,
+ int fir_vinc, int five_taps,
+ enum omap_color_component color_comp)
+{
+ const struct dispc_coef *h_coef, *v_coef;
int i;

- if (hscaleup)
- h_coef = coef_hup;
- else
- h_coef = coef_hdown;
-
- if (vscaleup)
- v_coef = five_taps ? coef_vup_5tap : coef_vup_3tap;
- else
- v_coef = five_taps ? coef_vdown_5tap : coef_vdown_3tap;
+ h_coef = dispc_ovl_get_scale_coef(fir_hinc, true);
+ v_coef = dispc_ovl_get_scale_coef(fir_vinc, five_taps);

for (i = 0; i < 8; i++) {
u32 h, hv;

- h = FLD_VAL(h_coef[i].hc0, 7, 0)
- | FLD_VAL(h_coef[i].hc1, 15, 8)
- | FLD_VAL(h_coef[i].hc2, 23, 16)
- | FLD_VAL(h_coef[i].hc3, 31, 24);
- hv = FLD_VAL(h_coef[i].hc4, 7, 0)
- | FLD_VAL(v_coef[i].vc0, 15, 8)
- | FLD_VAL(v_coef[i].vc1, 23, 16)
- | FLD_VAL(v_coef[i].vc2, 31, 24);
+ h = FLD_VAL(h_coef[i].hc0_vc00, 7, 0)
+ | FLD_VAL(h_coef[i].hc1_vc0, 15, 8)
+ | FLD_VAL(h_coef[i].hc2_vc1, 23, 16)
+ | FLD_VAL(h_coef[i].hc3_vc2, 31, 24);
+ hv = FLD_VAL(h_coef[i].hc4_vc22, 7, 0)
+ | FLD_VAL(v_coef[i].hc1_vc0, 15, 8)
+ | FLD_VAL(v_coef[i].hc2_vc1, 23, 16)
+ | FLD_VAL(v_coef[i].hc3_vc2, 31, 24);

if (color_comp == DISPC_COLOR_COMPONENT_RGB_Y) {
dispc_ovl_write_firh_reg(plane, i, h);
@@ -645,8 +551,8 @@ static void dispc_ovl_set_scale_coef(enum omap_plane plane, int hscaleup,
if (five_taps) {
for (i = 0; i < 8; i++) {
u32 v;
- v = FLD_VAL(v_coef[i].vc00, 7, 0)
- | FLD_VAL(v_coef[i].vc22, 15, 8);
+ v = FLD_VAL(v_coef[i].hc0_vc00, 7, 0)
+ | FLD_VAL(v_coef[i].hc4_vc22, 15, 8);
if (color_comp == DISPC_COLOR_COMPONENT_RGB_Y)
dispc_ovl_write_firv_reg(plane, i, v);
else
@@ -1168,17 +1074,12 @@ static void dispc_ovl_set_scale_param(enum omap_plane plane,
enum omap_color_component color_comp)
{
int fir_hinc, fir_vinc;
- int hscaleup, vscaleup;
-
- hscaleup = orig_width <= out_width;
- vscaleup = orig_height <= out_height;
-
- dispc_ovl_set_scale_coef(plane, hscaleup, vscaleup, five_taps,
- color_comp);

fir_hinc = 1024 * orig_width / out_width;
fir_vinc = 1024 * orig_height / out_height;

+ dispc_ovl_set_scale_coef(plane, fir_hinc, fir_vinc, five_taps,
+ color_comp);
dispc_ovl_set_fir(plane, fir_hinc, fir_vinc, color_comp);
}

diff --git a/drivers/video/omap2/dss/dispc.h b/drivers/video/omap2/dss/dispc.h
index c06efc3..5836bd1 100644
--- a/drivers/video/omap2/dss/dispc.h
+++ b/drivers/video/omap2/dss/dispc.h
@@ -97,6 +97,17 @@
#define DISPC_OVL_PRELOAD(n) (DISPC_OVL_BASE(n) + \
DISPC_PRELOAD_OFFSET(n))

+/* DISPC up/downsampling FIR filter coefficient structure */
+struct dispc_coef {
+ s8 hc4_vc22;
+ s8 hc3_vc2;
+ u8 hc2_vc1;
+ s8 hc1_vc0;
+ s8 hc0_vc00;
+};
+
+const struct dispc_coef *dispc_ovl_get_scale_coef(int inc, int five_taps);
+
/* DISPC manager/channel specific registers */
static inline u16 DISPC_DEFAULT_COLOR(enum omap_channel channel)
{
diff --git a/drivers/video/omap2/dss/dispc_coefs.c b/drivers/video/omap2/dss/dispc_coefs.c
new file mode 100644
index 0000000..e87b94f
--- /dev/null
+++ b/drivers/video/omap2/dss/dispc_coefs.c
@@ -0,0 +1,327 @@
+/*
+ * linux/drivers/video/omap2/dss/dispc_coefs.c
+ *
+ * Copyright (C) 2011 Texas Instruments
+ * Author: Chandrabhanu Mahapatra <cmahapatra@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/kernel.h>
+#include <video/omapdss.h>
+#include "dispc.h"
+
+#define ARRAY_LEN(array) (sizeof(array) / sizeof(array[0]))
+
+static const struct dispc_coef coef3_M8[8] = {
+ { 0, 0, 128, 0, 0 },
+ { 0, -4, 123, 9, 0 },
+ { 0, -4, 108, 87, 0 },
+ { 0, -2, 87, 43, 0 },
+ { 0, 64, 64, 0, 0 },
+ { 0, 43, 87, -2, 0 },
+ { 0, 24, 108, -4, 0 },
+ { 0, 9, 123, -4, 0 },
+};
+
+static const struct dispc_coef coef3_M9[8] = {
+ { 0, 6, 116, 6, 0 },
+ { 0, 0, 112, 16, 0 },
+ { 0, -2, 100, 30, 0 },
+ { 0, -2, 83, 47, 0 },
+ { 0, 64, 64, 0, 0 },
+ { 0, 47, 83, -2, 0 },
+ { 0, 30, 100, -2, 0 },
+ { 0, 16, 112, 0, 0 },
+};
+
+static const struct dispc_coef coef3_M10[8] = {
+ { 0, 10, 108, 10, 0 },
+ { 0, 3, 104, 21, 0 },
+ { 0, 0, 94, 34, 0 },
+ { 0, -1, 80, 49, 0 },
+ { 0, 64, 64, 0, 0 },
+ { 0, 49, 80, -1, 0 },
+ { 0, 34, 94, 0, 0 },
+ { 0, 21, 104, 3, 0 },
+};
+
+static const struct dispc_coef coef3_M11[8] = {
+ { 0, 14, 100, 14, 0 },
+ { 0, 6, 98, 24, 0 },
+ { 0, 2, 90, 36, 0 },
+ { 0, 0, 78, 50, 0 },
+ { 0, 64, 64, 0, 0 },
+ { 0, 50, 78, 0, 0 },
+ { 0, 36, 90, 2, 0 },
+ { 0, 24, 98, 6, 0 },
+};
+
+static const struct dispc_coef coef3_M12[8] = {
+ { 0, 16, 96, 16, 0 },
+ { 0, 9, 93, 26, 0 },
+ { 0, 4, 86, 38, 0 },
+ { 0, 1, 76, 51, 0 },
+ { 0, 64, 64, 0, 0 },
+ { 0, 51, 76, 1, 0 },
+ { 0, 38, 86, 4, 0 },
+ { 0, 26, 93, 9, 0 },
+};
+
+static const struct dispc_coef coef3_M13[8] = {
+ { 0, 18, 92, 18, 0 },
+ { 0, 10, 90, 28, 0 },
+ { 0, 5, 83, 40, 0 },
+ { 0, 1, 75, 52, 0 },
+ { 0, 64, 64, 0, 0 },
+ { 0, 52, 75, 1, 0 },
+ { 0, 40, 83, 5, 0 },
+ { 0, 28, 90, 10, 0 },
+};
+
+static const struct dispc_coef coef3_M14[8] = {
+ { 0, 20, 88, 20, 0 },
+ { 0, 12, 86, 30, 0 },
+ { 0, 6, 81, 41, 0 },
+ { 0, 2, 74, 52, 0 },
+ { 0, 64, 64, 0, 0 },
+ { 0, 52, 74, 2, 0 },
+ { 0, 41, 81, 6, 0 },
+ { 0, 30, 86, 12, 0 },
+};
+
+static const struct dispc_coef coef3_M16[8] = {
+ { 0, 22, 84, 22, 0 },
+ { 0, 14, 82, 32, 0 },
+ { 0, 8, 78, 42, 0 },
+ { 0, 3, 72, 53, 0 },
+ { 0, 64, 64, 0, 0 },
+ { 0, 53, 72, 3, 0 },
+ { 0, 42, 78, 8, 0 },
+ { 0, 32, 82, 14, 0 },
+};
+
+static const struct dispc_coef coef3_M19[8] = {
+ { 0, 24, 80, 24, 0 },
+ { 0, 16, 79, 33, 0 },
+ { 0, 9, 76, 43, 0 },
+ { 0, 4, 70, 54, 0 },
+ { 0, 64, 64, 0, 0 },
+ { 0, 54, 70, 4, 0 },
+ { 0, 43, 76, 9, 0 },
+ { 0, 33, 79, 16, 0 },
+};
+
+static const struct dispc_coef coef3_M22[8] = {
+ { 0, 25, 78, 25, 0 },
+ { 0, 17, 77, 34, 0 },
+ { 0, 10, 74, 44, 0 },
+ { 0, 5, 69, 54, 0 },
+ { 0, 64, 64, 0, 0 },
+ { 0, 54, 69, 5, 0 },
+ { 0, 44, 74, 10, 0 },
+ { 0, 34, 77, 17, 0 },
+};
+
+static const struct dispc_coef coef3_M26[8] = {
+ { 0, 26, 76, 26, 0 },
+ { 0, 19, 74, 35, 0 },
+ { 0, 11, 72, 45, 0 },
+ { 0, 5, 69, 54, 0 },
+ { 0, 64, 64, 0, 0 },
+ { 0, 54, 69, 5, 0 },
+ { 0, 45, 72, 11, 0 },
+ { 0, 35, 74, 19, 0 },
+};
+
+static const struct dispc_coef coef3_M32[8] = {
+ { 0, 27, 74, 27, 0 },
+ { 0, 19, 73, 36, 0 },
+ { 0, 12, 71, 45, 0 },
+ { 0, 6, 68, 54, 0 },
+ { 0, 64, 64, 0, 0 },
+ { 0, 54, 68, 6, 0 },
+ { 0, 45, 71, 12, 0 },
+ { 0, 36, 73, 19, 0 },
+};
+
+static const struct dispc_coef coef5_M8[8] = {
+ { 0, 0, 128, 0, 0 },
+ { -2, 14, 125, -10, 1 },
+ { -6, 33, 114, -15, 2 },
+ { -10, 55, 98, -16, 1 },
+ { 0, -14, 78, 78, -14 },
+ { 1, -16, 98, 55, -10 },
+ { 2, -15, 114, 33, -6 },
+ { 1, -10, 125, 14, -2 },
+};
+
+static const struct dispc_coef coef5_M9[8] = {
+ { -3, 10, 114, 10, -3 },
+ { -6, 24, 110, 0, -1 },
+ { -8, 40, 103, -7, 0 },
+ { -11, 58, 91, -11, 1 },
+ { 0, -12, 76, 76, -12 },
+ { 1, -11, 91, 58, -11 },
+ { 0, -7, 103, 40, -8 },
+ { -1, 0, 111, 24, -6 },
+};
+
+static const struct dispc_coef coef5_M10[8] = {
+ { -4, 18, 100, 18, -4 },
+ { -6, 30, 99, 8, -3 },
+ { -8, 44, 93, 0, -1 },
+ { -9, 58, 84, -5, 0 },
+ { 0, -8, 72, 72, -8 },
+ { 0, -5, 84, 58, -9 },
+ { -1, 0, 93, 44, -8 },
+ { -3, 8, 99, 30, -6 },
+};
+
+static const struct dispc_coef coef5_M11[8] = {
+ { -5, 23, 92, 23, -5 },
+ { -6, 34, 90, 13, -3 },
+ { -6, 45, 85, 6, -2 },
+ { -6, 57, 78, 0, -1 },
+ { 0, -4, 68, 68, -4 },
+ { -1, 0, 78, 57, -6 },
+ { -2, 6, 85, 45, -6 },
+ { -3, 13, 90, 34, -6 },
+};
+
+static const struct dispc_coef coef5_M12[8] = {
+ { -4, 26, 84, 26, -4 },
+ { -5, 36, 82, 18, -3 },
+ { -4, 46, 78, 10, -2 },
+ { -3, 55, 72, 5, -1 },
+ { 0, 0, 64, 64, 0 },
+ { -1, 5, 72, 55, -3 },
+ { -2, 10, 78, 46, -4 },
+ { -3, 18, 82, 36, -5 },
+};
+
+static const struct dispc_coef coef5_M13[8] = {
+ { -3, 28, 78, 28, -3 },
+ { -3, 37, 76, 21, -3 },
+ { -2, 45, 73, 14, -2 },
+ { 0, 53, 68, 8, -1 },
+ { 0, 3, 61, 61, 3 },
+ { -1, 8, 68, 53, 0 },
+ { -2, 14, 73, 45, -2 },
+ { -3, 21, 76, 37, -3 },
+};
+
+static const struct dispc_coef coef5_M14[8] = {
+ { -2, 30, 72, 30, -2 },
+ { -1, 37, 71, 23, -2 },
+ { 0, 45, 69, 16, -2 },
+ { 3, 52, 64, 10, -1 },
+ { 0, 6, 58, 58, 6 },
+ { -1, 10, 64, 52, 3 },
+ { -2, 16, 69, 45, 0 },
+ { -2, 23, 71, 37, -1 },
+};
+
+static const struct dispc_coef coef5_M16[8] = {
+ { 0, 31, 66, 31, 0 },
+ { 1, 38, 65, 25, -1 },
+ { 3, 44, 62, 20, -1 },
+ { 6, 49, 59, 14, 0 },
+ { 0, 10, 54, 54, 10 },
+ { 0, 14, 59, 49, 6 },
+ { -1, 20, 62, 44, 3 },
+ { -1, 25, 65, 38, 1 },
+};
+
+static const struct dispc_coef coef5_M19[8] = {
+ { 3, 32, 58, 32, 3 },
+ { 4, 38, 58, 27, 1 },
+ { 7, 42, 55, 23, 1 },
+ { 10, 46, 54, 18, 0 },
+ { 0, 14, 50, 50, 14 },
+ { 0, 18, 54, 46, 10 },
+ { 1, 23, 55, 42, 7 },
+ { 1, 27, 58, 38, 4 },
+};
+
+static const struct dispc_coef coef5_M22[8] = {
+ { 4, 33, 54, 33, 4 },
+ { 6, 37, 54, 28, 3 },
+ { 9, 41, 53, 24, 1 },
+ { 12, 45, 51, 20, 0 },
+ { 0, 16, 48, 48, 16 },
+ { 0, 20, 51, 45, 12 },
+ { 1, 24, 53, 41, 9 },
+ { 3, 28, 54, 37, 6 },
+};
+
+static const struct dispc_coef coef5_M26[8] = {
+ { 6, 33, 50, 33, 6 },
+ { 8, 36, 51, 29, 4 },
+ { 11, 40, 50, 25, 2 },
+ { 14, 43, 48, 22, 1 },
+ { 0, 18, 46, 46, 18 },
+ { 1, 22, 48, 43, 14 },
+ { 2, 25, 50, 40, 11 },
+ { 4, 29, 51, 36, 8 },
+};
+
+static const struct dispc_coef coef5_M32[8] = {
+ { 7, 33, 48, 33, 7 },
+ { 10, 36, 48, 29, 5 },
+ { 13, 39, 47, 26, 3 },
+ { 16, 42, 46, 23, 1 },
+ { 0, 19, 45, 45, 19 },
+ { 1, 23, 46, 42, 16 },
+ { 3, 26, 47, 39, 13 },
+ { 5, 29, 48, 36, 10 },
+};
+
+const struct dispc_coef *dispc_ovl_get_scale_coef(int inc, int five_taps)
+{
+ int i;
+ static const struct {
+ int Mmin;
+ int Mmax;
+ const struct dispc_coef *coef_3;
+ const struct dispc_coef *coef_5;
+ } coefs[] = {
+ { 26, 32, coef3_M32, coef5_M32 },
+ { 22, 26, coef3_M26, coef5_M26 },
+ { 19, 22, coef3_M22, coef5_M22 },
+ { 16, 19, coef3_M19, coef5_M19 },
+ { 14, 16, coef3_M16, coef5_M16 },
+ { 13, 14, coef3_M14, coef5_M14 },
+ { 12, 13, coef3_M13, coef5_M13 },
+ { 11, 12, coef3_M12, coef5_M12 },
+ { 10, 11, coef3_M11, coef5_M11 },
+ { 9, 10, coef3_M10, coef5_M10 },
+ { 8, 9, coef3_M9, coef5_M9 },
+ { 3, 8, coef3_M8, coef5_M8 },
+ /*
+ * When upscaling more than two times, blockiness and outlines
+ * around the image are observed when M8 tables are used. M11,
+ * M16 and M19 tables are used to prevent this.
+ */
+ { 2, 3, coef3_M11, coef5_M11 },
+ { 1, 2, coef3_M16, coef5_M16 },
+ };
+
+ inc /= 128;
+ for (i = 0; i < ARRAY_LEN(coefs); ++i)
+ if (inc > coefs[i].Mmin && inc <= coefs[i].Mmax)
+ return five_taps ? coefs[i].coef_5 : coefs[i].coef_3;
+ if (inc == 1)
+ return five_taps ? coef3_M19 : coef5_M19;
+ return NULL;
+}
--
1.7.1