Hi,
With this mail there is a patch that adds a "rgblut" filter to module "plus".
The "rgblut" filter provides a simple string based interface to
implement color correction with look-up tables.
The motivation for this plugin came when I was implementing GUI
component for a Catmull-Rom curves filter, and realized that I would
have to re-implment the same code in C to get the feature working.
Then I realized that _all_color correction is implemented as look-up
tables, so to get arbitary color corretion for my Python application I
would only need a single filter that would read the look-up tables
from properties, and then apply those tables to each channel.
The "rgblut" filter has three properties "R_table","G_table" and
"B_table". Correct input for each property is a string that contains
256 half-comma separated integer values in range 0 - 255, for example:
"0;1;2;3;4;5...253;254;255" for a no-op look-up table. If a correct
number of tokens is not found in the input, then a no-op look-up table
is used instead.
Having this filter availeble in MLT would enable Flowblade to quickly
and easily implement a lot of different color correction, so please
add this to MLT.
Regards,
Janne Liljeblad
From 7ae6cca79fdc9a13f0e8469467f42b6f15bcaf28 Mon Sep 17 00:00:00 2001
From: Janne Liljeblad <janne.liljeb...@gmail.com>
Date: Mon, 10 Feb 2014 00:33:42 +0200
Subject: [PATCH] Add rgblut filter
---
src/modules/plus/Makefile | 1 +
src/modules/plus/factory.c | 3 +
src/modules/plus/filter_rgblut.c | 136 +++++++++++++++++++++++++++++++++++++
src/modules/plus/filter_rgblut.yml | 47 +++++++++++++
4 files changed, 187 insertions(+)
create mode 100644 src/modules/plus/filter_rgblut.c
create mode 100644 src/modules/plus/filter_rgblut.yml
diff --git a/src/modules/plus/Makefile b/src/modules/plus/Makefile
index 8102a1b..c96f4b9 100644
--- a/src/modules/plus/Makefile
+++ b/src/modules/plus/Makefile
@@ -13,6 +13,7 @@ OBJS = consumer_blipflash.o \
filter_dynamictext.o \
filter_invert.o \
filter_loudness.o \
+ filter_rgblut.o \
filter_sepia.o \
producer_blipflash.o \
producer_count.o \
diff --git a/src/modules/plus/factory.c b/src/modules/plus/factory.c
index a739957..92989e3 100644
--- a/src/modules/plus/factory.c
+++ b/src/modules/plus/factory.c
@@ -28,6 +28,7 @@ extern mlt_filter filter_charcoal_init( mlt_profile profile, mlt_service_type ty
extern mlt_filter filter_dynamictext_init( mlt_profile profile, mlt_service_type type, const char *id, char *arg );
extern mlt_filter filter_loudness_init( mlt_profile profile, mlt_service_type type, const char *id, char *arg );
extern mlt_filter filter_invert_init( mlt_profile profile, mlt_service_type type, const char *id, char *arg );
+extern mlt_filter filter_rgblut_init( mlt_profile profile, mlt_service_type type, const char *id, char *arg );
extern mlt_filter filter_sepia_init( mlt_profile profile, mlt_service_type type, const char *id, char *arg );
extern mlt_producer producer_blipflash_init( mlt_profile profile, mlt_service_type type, const char *id, char *arg );
extern mlt_producer producer_count_init( const char *arg );
@@ -48,6 +49,7 @@ MLT_REPOSITORY
MLT_REGISTER( filter_type, "dynamictext", filter_dynamictext_init );
MLT_REGISTER( filter_type, "invert", filter_invert_init );
MLT_REGISTER( filter_type, "loudness", filter_loudness_init );
+ MLT_REGISTER( filter_type, "rgblut", filter_rgblut_init );
MLT_REGISTER( filter_type, "sepia", filter_sepia_init );
MLT_REGISTER( producer_type, "blipflash", producer_blipflash_init );
MLT_REGISTER( producer_type, "count", producer_count_init );
@@ -59,6 +61,7 @@ MLT_REPOSITORY
MLT_REGISTER_METADATA( filter_type, "dynamictext", metadata, "filter_dynamictext.yml" );
MLT_REGISTER_METADATA( filter_type, "invert", metadata, "filter_invert.yml" );
MLT_REGISTER_METADATA( filter_type, "loudness", metadata, "filter_loudness.yml" );
+ MLT_REGISTER_METADATA( filter_type, "rgblut", metadata, "filter_rgblut.yml" );
MLT_REGISTER_METADATA( filter_type, "sepia", metadata, "filter_sepia.yml" );
MLT_REGISTER_METADATA( producer_type, "blipflash", metadata, "producer_blipflash.yml" );
MLT_REGISTER_METADATA( producer_type, "count", metadata, "producer_count.yml" );
diff --git a/src/modules/plus/filter_rgblut.c b/src/modules/plus/filter_rgblut.c
new file mode 100644
index 0000000..9eddf31
--- /dev/null
+++ b/src/modules/plus/filter_rgblut.c
@@ -0,0 +1,136 @@
+/*
+ * filter_rgblut.c -- generic RGB look-up table filter with string interface
+ * Copyright (C) 2014 Janne Liljeblad
+ * Author: Janne Liljeblad
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <framework/mlt_filter.h>
+#include <framework/mlt_frame.h>
+#include <framework/mlt_tokeniser.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <string.h>
+
+/** Fill channel lut with integers parsed from property string.
+*/
+static void fill_channel_lut(int lut[], char* channel_table_str)
+{
+ mlt_tokeniser tokeniser = mlt_tokeniser_init();
+ mlt_tokeniser_parse_new( tokeniser, channel_table_str, ";" );
+
+ // Only create lut from string if tokens count exactly right
+ if ( tokeniser->count == 256 )
+ {
+ // Fill lut with token values
+ int i;
+ int val;
+ for( i = 0; i < 256; i++ )
+ {
+ val = atoi(tokeniser->tokens[i]);
+ lut[i] = val;
+ }
+ }
+ else
+ {
+ // Fill lut with linear no-op table
+ int i;
+ for( i = 0; i < 256; i++ )
+ {
+ lut[i] = i;
+ }
+ }
+ mlt_tokeniser_close( tokeniser );
+}
+
+/** Do it :-).
+*/
+static int filter_get_image( mlt_frame this, uint8_t **image, mlt_image_format *format, int *width, int *height, int writable )
+{
+ // Get the image
+ mlt_filter filter = mlt_frame_pop_service( this );
+
+ *format = mlt_image_rgb24;
+ int error = mlt_frame_get_image( this, image, format, width, height, 0 );
+
+ // Only process if we have no error and a valid colour space
+ if ( error == 0 )
+ {
+ // Create lut tables from properties for each RGB channel
+ char* r_str = mlt_properties_get( MLT_FRAME_PROPERTIES( this ), "R_table" );
+ int r_lut[256];
+ fill_channel_lut( r_lut, r_str );
+
+ char* g_str = mlt_properties_get( MLT_FRAME_PROPERTIES( this ), "G_table" );
+ int g_lut[256];
+ fill_channel_lut( g_lut, g_str );
+
+ char* b_str = mlt_properties_get( MLT_FRAME_PROPERTIES( this ), "B_table" );
+ int b_lut[256];
+ fill_channel_lut( b_lut, b_str );
+
+ // Apply look-uo tables into image
+ int i = *width * *height + 1;
+ uint8_t *p = *image;
+ uint8_t *r = *image;
+ while ( --i )
+ {
+ *p ++ = r_lut[ *r ++ ];
+ *p ++ = g_lut[ *r ++ ];
+ *p ++ = b_lut[ *r ++ ];
+ }
+ }
+
+ return error;
+}
+
+/** Filter processing.
+*/
+
+static mlt_frame filter_process( mlt_filter this, mlt_frame frame )
+{
+ char* r_table = mlt_properties_get( MLT_FILTER_PROPERTIES( this ), "R_table" );
+ char* g_table = mlt_properties_get( MLT_FILTER_PROPERTIES( this ), "G_table" );
+ char* b_table = mlt_properties_get( MLT_FILTER_PROPERTIES( this ), "B_table" );
+
+ mlt_properties_set( MLT_FRAME_PROPERTIES( frame ), "R_table", r_table );
+ mlt_properties_set( MLT_FRAME_PROPERTIES( frame ), "G_table", g_table );
+ mlt_properties_set( MLT_FRAME_PROPERTIES( frame ), "B_table", b_table );
+
+ // Push the frame filter
+ mlt_frame_push_service( frame, this );
+ mlt_frame_push_get_image( frame, filter_get_image );
+ return frame;
+}
+
+/** Constructor for the filter.
+*/
+
+mlt_filter filter_rgblut_init( mlt_profile profile, mlt_service_type type, const char *id, char *arg )
+{
+ mlt_filter this = mlt_filter_new( );
+ if ( this != NULL )
+ {
+ this->process = filter_process;
+ mlt_properties_set( MLT_FILTER_PROPERTIES( this ), "R_table", "unset" );
+ mlt_properties_set( MLT_FILTER_PROPERTIES( this ), "G_table", "unset" );
+ mlt_properties_set( MLT_FILTER_PROPERTIES( this ), "B_table", "unset" );
+ }
+ return this;
+}
+
diff --git a/src/modules/plus/filter_rgblut.yml b/src/modules/plus/filter_rgblut.yml
new file mode 100644
index 0000000..93e8849
--- /dev/null
+++ b/src/modules/plus/filter_rgblut.yml
@@ -0,0 +1,47 @@
+schema_version: 0.1
+type: filter
+identifier: rgblut
+title: RGBLUT
+version: 1
+copyright: Janne Liljeblad
+creator: Janne Liljeblad
+license: LGPLv2.1
+language: en
+tags:
+ - Video
+description:
+ Converts input strings with exactly 256 half-comma separated integer values in
+ range 0 - 255 to look-up tables that then used to modify R, G, B values.
+
+ This creates a generic string interface for color correction.
+
+parameters:
+ - identifier: R_table
+ title: Red channel look-up table
+ type: string
+ default: unset
+ description: >
+ Value is tokenised using half-comma separator into exactly 256 integer
+ values in range 0 - 255 and a loop-up table for red channel values is
+ created and applied to image. If tokenising of value fails a linear table
+ that returns input values unchanged is used instead.
+
+ - identifier: G_table
+ title: Green channel look-up table
+ type: string
+ default: unset
+ description: >
+ Value is tokenised using half-comma separator into exactly 256 integer
+ values in range 0 - 255 and a loop-up table for green channel values is
+ created and applied to image. If tokenising of value fails a linear table
+ that returns input values unchanged is used instead.
+
+ - identifier: B_table
+ title: Blue channel look-up table
+ type: string
+ default: unset
+ description: >
+ Value is tokenised using half-comma separator into exactly 256 integer
+ values in range 0 - 255 and a loop-up table for green channel values is
+ created and applied to image. If tokenising of value fails a linear table
+ that returns input values unchanged is used instead.
--
1.8.3.2
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