2 * Copyright (c) 2010 Nolan Lum <nol888@gmail.com>
3 * Copyright (c) 2009 Loren Merritt <lorenm@u.washington.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 * For each pixel, if it is within the threshold of the blurred value, make it
30 * closer. So now we have a smoothed and higher bitdepth version of all the
31 * shallow 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/opt.h"
39 #include "libavutil/pixdesc.h"
46 DECLARE_ALIGNED(16, static const uint16_t, dither)[8][8] = {
47 {0x00,0x60,0x18,0x78,0x06,0x66,0x1E,0x7E},
48 {0x40,0x20,0x58,0x38,0x46,0x26,0x5E,0x3E},
49 {0x10,0x70,0x08,0x68,0x16,0x76,0x0E,0x6E},
50 {0x50,0x30,0x48,0x28,0x56,0x36,0x4E,0x2E},
51 {0x04,0x64,0x1C,0x7C,0x02,0x62,0x1A,0x7A},
52 {0x44,0x24,0x5C,0x3C,0x42,0x22,0x5A,0x3A},
53 {0x14,0x74,0x0C,0x6C,0x12,0x72,0x0A,0x6A},
54 {0x54,0x34,0x4C,0x2C,0x52,0x32,0x4A,0x2A},
57 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)
60 for (x = 0; x < width; dc += x & 1, x++) {
61 int pix = src[x] << 7;
62 int delta = dc[0] - pix;
63 int m = abs(delta) * thresh >> 16;
64 m = FFMAX(0, 127 - m);
65 m = m * m * delta >> 14;
66 pix += m + dithers[x & 7];
67 dst[x] = av_clip_uint8(pix >> 7);
71 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)
74 for (x = 0; x < width; x++) {
75 v = buf1[x] + src[2 * x] + src[2 * x + 1] + src[2 * x + src_linesize] + src[2 * x + 1 + src_linesize];
82 static void filter(GradFunContext *ctx, uint8_t *dst, const uint8_t *src, int width, int height, int dst_linesize, int src_linesize, int r)
84 int bstride = FFALIGN(width, 16) / 2;
86 uint32_t dc_factor = (1 << 21) / (r * r);
87 uint16_t *dc = ctx->buf + 16;
88 uint16_t *buf = ctx->buf + bstride + 32;
89 int thresh = ctx->thresh;
91 memset(dc, 0, (bstride + 16) * sizeof(*buf));
92 for (y = 0; y < r; y++)
93 ctx->blur_line(dc, buf + y * bstride, buf + (y - 1) * bstride, src + 2 * y * src_linesize, src_linesize, width / 2);
96 int mod = ((y + r) / 2) % r;
97 uint16_t *buf0 = buf + mod * bstride;
98 uint16_t *buf1 = buf + (mod ? mod - 1 : r - 1) * bstride;
100 ctx->blur_line(dc, buf0, buf1, src + (y + r) * src_linesize, src_linesize, width / 2);
101 for (x = v = 0; x < r; x++)
103 for (; x < width / 2; x++) {
104 v += dc[x] - dc[x-r];
105 dc[x-r] = v * dc_factor >> 16;
107 for (; x < (width + r + 1) / 2; x++)
108 dc[x-r] = v * dc_factor >> 16;
109 for (x = -r / 2; x < 0; x++)
113 for (y = 0; y < r; y++)
114 ctx->filter_line(dst + y * dst_linesize, src + y * src_linesize, dc - r / 2, width, thresh, dither[y & 7]);
116 ctx->filter_line(dst + y * dst_linesize, src + y * src_linesize, dc - r / 2, width, thresh, dither[y & 7]);
117 if (++y >= height) break;
118 ctx->filter_line(dst + y * dst_linesize, src + y * src_linesize, dc - r / 2, width, thresh, dither[y & 7]);
119 if (++y >= height) break;
124 static av_cold int init(AVFilterContext *ctx)
126 GradFunContext *s = ctx->priv;
128 s->thresh = (1 << 15) / s->strength;
129 s->radius = av_clip((s->radius + 1) & ~1, 4, 32);
131 s->blur_line = ff_gradfun_blur_line_c;
132 s->filter_line = ff_gradfun_filter_line_c;
135 ff_gradfun_init_x86(s);
137 av_log(ctx, AV_LOG_VERBOSE, "threshold:%.2f radius:%d\n", s->strength, s->radius);
142 static av_cold void uninit(AVFilterContext *ctx)
144 GradFunContext *s = ctx->priv;
148 static int query_formats(AVFilterContext *ctx)
150 static const enum AVPixelFormat pix_fmts[] = {
151 AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV420P,
152 AV_PIX_FMT_GRAY8, AV_PIX_FMT_YUV444P,
153 AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV411P,
158 AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
160 return AVERROR(ENOMEM);
161 return ff_set_common_formats(ctx, fmts_list);
164 static int config_input(AVFilterLink *inlink)
166 GradFunContext *s = inlink->dst->priv;
167 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
168 int hsub = desc->log2_chroma_w;
169 int vsub = desc->log2_chroma_h;
172 s->buf = av_calloc((FFALIGN(inlink->w, 16) * (s->radius + 1) / 2 + 32), sizeof(*s->buf));
174 return AVERROR(ENOMEM);
176 s->chroma_w = AV_CEIL_RSHIFT(inlink->w, hsub);
177 s->chroma_h = AV_CEIL_RSHIFT(inlink->h, vsub);
178 s->chroma_r = av_clip(((((s->radius >> hsub) + (s->radius >> vsub)) / 2 ) + 1) & ~1, 4, 32);
183 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
185 GradFunContext *s = inlink->dst->priv;
186 AVFilterLink *outlink = inlink->dst->outputs[0];
190 if (av_frame_is_writable(in)) {
195 out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
198 return AVERROR(ENOMEM);
200 av_frame_copy_props(out, in);
203 for (p = 0; p < 4 && in->data[p] && in->linesize[p]; p++) {
213 if (FFMIN(w, h) > 2 * r)
214 filter(s, out->data[p], in->data[p], w, h, out->linesize[p], in->linesize[p], r);
215 else if (out->data[p] != in->data[p])
216 av_image_copy_plane(out->data[p], out->linesize[p], in->data[p], in->linesize[p], w, h);
222 return ff_filter_frame(outlink, out);
225 #define OFFSET(x) offsetof(GradFunContext, x)
226 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
228 static const AVOption gradfun_options[] = {
229 { "strength", "The maximum amount by which the filter will change any one pixel.", OFFSET(strength), AV_OPT_TYPE_FLOAT, { .dbl = 1.2 }, 0.51, 64, FLAGS },
230 { "radius", "The neighborhood to fit the gradient to.", OFFSET(radius), AV_OPT_TYPE_INT, { .i64 = 16 }, 4, 32, FLAGS },
234 AVFILTER_DEFINE_CLASS(gradfun);
236 static const AVFilterPad avfilter_vf_gradfun_inputs[] = {
239 .type = AVMEDIA_TYPE_VIDEO,
240 .config_props = config_input,
241 .filter_frame = filter_frame,
246 static const AVFilterPad avfilter_vf_gradfun_outputs[] = {
249 .type = AVMEDIA_TYPE_VIDEO,
254 AVFilter ff_vf_gradfun = {
256 .description = NULL_IF_CONFIG_SMALL("Debands video quickly using gradients."),
257 .priv_size = sizeof(GradFunContext),
258 .priv_class = &gradfun_class,
261 .query_formats = query_formats,
262 .inputs = avfilter_vf_gradfun_inputs,
263 .outputs = avfilter_vf_gradfun_outputs,
264 .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,