2 * Copyright (c) 2010 Nolan Lum <nol888@gmail.com>
3 * Copyright (c) 2009 Loren Merritt <lorenm@u.washignton.edu>
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 * gradfun debanding filter, ported from MPlayer
25 * libmpcodecs/vf_gradfun.c
27 * Apply a boxblur debanding algorithm (based on the gradfun2db
28 * Avisynth filter by prunedtree).
29 * Foreach pixel, if it's within threshold of the blurred value, make it closer.
30 * So now we have a smoothed and higher bitdepth version of all the shallow
31 * gradients, while leaving detailed areas untouched.
32 * Dither it back to 8bit.
35 #include "libavutil/imgutils.h"
36 #include "libavutil/common.h"
37 #include "libavutil/cpu.h"
38 #include "libavutil/pixdesc.h"
39 #include "libavutil/opt.h"
46 #define OFFSET(x) offsetof(GradFunContext, x)
47 #define F AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
49 static const AVOption gradfun_options[] = {
50 { "strength", "set the maximum amount by which the filter will change any one pixel", OFFSET(strength), AV_OPT_TYPE_DOUBLE, {.dbl = 1.2}, 0.51, 64, F },
51 { "radius", "set the neighborhood to fit the gradient to", OFFSET(radius), AV_OPT_TYPE_INT, {.i64 = 16}, 4, 32, F },
55 AVFILTER_DEFINE_CLASS(gradfun);
57 DECLARE_ALIGNED(16, static const uint16_t, dither)[8][8] = {
58 {0x00,0x60,0x18,0x78,0x06,0x66,0x1E,0x7E},
59 {0x40,0x20,0x58,0x38,0x46,0x26,0x5E,0x3E},
60 {0x10,0x70,0x08,0x68,0x16,0x76,0x0E,0x6E},
61 {0x50,0x30,0x48,0x28,0x56,0x36,0x4E,0x2E},
62 {0x04,0x64,0x1C,0x7C,0x02,0x62,0x1A,0x7A},
63 {0x44,0x24,0x5C,0x3C,0x42,0x22,0x5A,0x3A},
64 {0x14,0x74,0x0C,0x6C,0x12,0x72,0x0A,0x6A},
65 {0x54,0x34,0x4C,0x2C,0x52,0x32,0x4A,0x2A},
68 void ff_gradfun_filter_line_c(uint8_t *dst, const uint8_t *src, const uint16_t *dc, int width, int thresh, const uint16_t *dithers)
71 for (x = 0; x < width; dc += x & 1, x++) {
72 int pix = src[x] << 7;
73 int delta = dc[0] - pix;
74 int m = abs(delta) * thresh >> 16;
75 m = FFMAX(0, 127 - m);
76 m = m * m * delta >> 14;
77 pix += m + dithers[x & 7];
78 dst[x] = av_clip_uint8(pix >> 7);
82 void ff_gradfun_blur_line_c(uint16_t *dc, uint16_t *buf, const uint16_t *buf1, const uint8_t *src, int src_linesize, int width)
85 for (x = 0; x < width; x++) {
86 v = buf1[x] + src[2 * x] + src[2 * x + 1] + src[2 * x + src_linesize] + src[2 * x + 1 + src_linesize];
93 static void filter(GradFunContext *ctx, uint8_t *dst, const uint8_t *src, int width, int height, int dst_linesize, int src_linesize, int r)
95 int bstride = FFALIGN(width, 16) / 2;
97 uint32_t dc_factor = (1 << 21) / (r * r);
98 uint16_t *dc = ctx->buf + 16;
99 uint16_t *buf = ctx->buf + bstride + 32;
100 int thresh = ctx->thresh;
102 memset(dc, 0, (bstride + 16) * sizeof(*buf));
103 for (y = 0; y < r; y++)
104 ctx->blur_line(dc, buf + y * bstride, buf + (y - 1) * bstride, src + 2 * y * src_linesize, src_linesize, width / 2);
106 if (y < height - r) {
107 int mod = ((y + r) / 2) % r;
108 uint16_t *buf0 = buf + mod * bstride;
109 uint16_t *buf1 = buf + (mod ? mod - 1 : r - 1) * bstride;
111 ctx->blur_line(dc, buf0, buf1, src + (y + r) * src_linesize, src_linesize, width / 2);
112 for (x = v = 0; x < r; x++)
114 for (; x < width / 2; x++) {
115 v += dc[x] - dc[x-r];
116 dc[x-r] = v * dc_factor >> 16;
118 for (; x < (width + r + 1) / 2; x++)
119 dc[x-r] = v * dc_factor >> 16;
120 for (x = -r / 2; x < 0; x++)
124 for (y = 0; y < r; y++)
125 ctx->filter_line(dst + y * dst_linesize, src + y * src_linesize, dc - r / 2, width, thresh, dither[y & 7]);
127 ctx->filter_line(dst + y * dst_linesize, src + y * src_linesize, dc - r / 2, width, thresh, dither[y & 7]);
128 if (++y >= height) break;
129 ctx->filter_line(dst + y * dst_linesize, src + y * src_linesize, dc - r / 2, width, thresh, dither[y & 7]);
130 if (++y >= height) break;
134 static av_cold int init(AVFilterContext *ctx, const char *args)
137 GradFunContext *gf = ctx->priv;
138 static const char *shorthand[] = { "strength", "radius", NULL };
140 gf->class = &gradfun_class;
141 av_opt_set_defaults(gf);
143 if ((ret = av_opt_set_from_string(gf, args, shorthand, "=", ":")) < 0)
146 gf->thresh = (1 << 15) / gf->strength;
147 gf->radius = av_clip((gf->radius + 1) & ~1, 4, 32);
149 gf->blur_line = ff_gradfun_blur_line_c;
150 gf->filter_line = ff_gradfun_filter_line_c;
153 ff_gradfun_init_x86(gf);
155 av_log(ctx, AV_LOG_VERBOSE, "threshold:%.2f radius:%d\n", gf->strength, gf->radius);
160 static av_cold void uninit(AVFilterContext *ctx)
162 GradFunContext *gf = ctx->priv;
166 static int query_formats(AVFilterContext *ctx)
168 static const enum AVPixelFormat pix_fmts[] = {
169 AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV420P,
170 AV_PIX_FMT_GRAY8, AV_PIX_FMT_NV12,
171 AV_PIX_FMT_NV21, AV_PIX_FMT_YUV444P,
172 AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV411P,
177 ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
182 static int config_input(AVFilterLink *inlink)
184 GradFunContext *gf = inlink->dst->priv;
185 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
186 int hsub = desc->log2_chroma_w;
187 int vsub = desc->log2_chroma_h;
189 gf->buf = av_mallocz((FFALIGN(inlink->w, 16) * (gf->radius + 1) / 2 + 32) * sizeof(uint16_t));
191 return AVERROR(ENOMEM);
193 gf->chroma_w = -((-inlink->w) >> hsub);
194 gf->chroma_h = -((-inlink->h) >> vsub);
195 gf->chroma_r = av_clip(((((gf->radius >> hsub) + (gf->radius >> vsub)) / 2 ) + 1) & ~1, 4, 32);
200 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *in)
202 GradFunContext *gf = inlink->dst->priv;
203 AVFilterLink *outlink = inlink->dst->outputs[0];
204 AVFilterBufferRef *out;
207 if (in->perms & AV_PERM_WRITE) {
211 out = ff_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
213 avfilter_unref_bufferp(&in);
214 return AVERROR(ENOMEM);
216 avfilter_copy_buffer_ref_props(out, in);
219 for (p = 0; p < 4 && in->data[p]; p++) {
229 if (FFMIN(w, h) > 2 * r)
230 filter(gf, out->data[p], in->data[p], w, h, out->linesize[p], in->linesize[p], r);
231 else if (out->data[p] != in->data[p])
232 av_image_copy_plane(out->data[p], out->linesize[p], in->data[p], in->linesize[p], w, h);
236 avfilter_unref_bufferp(&in);
238 return ff_filter_frame(outlink, out);
241 static const AVFilterPad avfilter_vf_gradfun_inputs[] = {
244 .type = AVMEDIA_TYPE_VIDEO,
245 .config_props = config_input,
246 .filter_frame = filter_frame,
247 .min_perms = AV_PERM_READ,
252 static const AVFilterPad avfilter_vf_gradfun_outputs[] = {
255 .type = AVMEDIA_TYPE_VIDEO,
260 AVFilter avfilter_vf_gradfun = {
262 .description = NULL_IF_CONFIG_SMALL("Debands video quickly using gradients."),
263 .priv_size = sizeof(GradFunContext),
266 .query_formats = query_formats,
267 .inputs = avfilter_vf_gradfun_inputs,
268 .outputs = avfilter_vf_gradfun_outputs,
269 .priv_class = &gradfun_class,