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 Libav.
7 * Libav 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 * Libav 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 Libav; 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/cpu.h"
37 #include "libavutil/pixdesc.h"
44 DECLARE_ALIGNED(16, static const uint16_t, dither)[8][8] = {
45 {0x00,0x60,0x18,0x78,0x06,0x66,0x1E,0x7E},
46 {0x40,0x20,0x58,0x38,0x46,0x26,0x5E,0x3E},
47 {0x10,0x70,0x08,0x68,0x16,0x76,0x0E,0x6E},
48 {0x50,0x30,0x48,0x28,0x56,0x36,0x4E,0x2E},
49 {0x04,0x64,0x1C,0x7C,0x02,0x62,0x1A,0x7A},
50 {0x44,0x24,0x5C,0x3C,0x42,0x22,0x5A,0x3A},
51 {0x14,0x74,0x0C,0x6C,0x12,0x72,0x0A,0x6A},
52 {0x54,0x34,0x4C,0x2C,0x52,0x32,0x4A,0x2A},
55 void ff_gradfun_filter_line_c(uint8_t *dst, uint8_t *src, uint16_t *dc, int width, int thresh, const uint16_t *dithers)
58 for (x = 0; x < width; x++, dc += x & 1) {
59 int pix = src[x] << 7;
60 int delta = dc[0] - pix;
61 int m = abs(delta) * thresh >> 16;
62 m = FFMAX(0, 127 - m);
63 m = m * m * delta >> 14;
64 pix += m + dithers[x & 7];
65 dst[x] = av_clip_uint8(pix >> 7);
69 void ff_gradfun_blur_line_c(uint16_t *dc, uint16_t *buf, uint16_t *buf1, uint8_t *src, int src_linesize, int width)
72 for (x = 0; x < width; x++) {
73 v = buf1[x] + src[2 * x] + src[2 * x + 1] + src[2 * x + src_linesize] + src[2 * x + 1 + src_linesize];
80 static void filter(GradFunContext *ctx, uint8_t *dst, uint8_t *src, int width, int height, int dst_linesize, int src_linesize, int r)
82 int bstride = FFALIGN(width, 16) / 2;
84 uint32_t dc_factor = (1 << 21) / (r * r);
85 uint16_t *dc = ctx->buf + 16;
86 uint16_t *buf = ctx->buf + bstride + 32;
87 int thresh = ctx->thresh;
89 memset(dc, 0, (bstride + 16) * sizeof(*buf));
90 for (y = 0; y < r; y++)
91 ctx->blur_line(dc, buf + y * bstride, buf + (y - 1) * bstride, src + 2 * y * src_linesize, src_linesize, width / 2);
94 int mod = ((y + r) / 2) % r;
95 uint16_t *buf0 = buf + mod * bstride;
96 uint16_t *buf1 = buf + (mod ? mod - 1 : r - 1) * bstride;
98 ctx->blur_line(dc, buf0, buf1, src + (y + r) * src_linesize, src_linesize, width / 2);
99 for (x = v = 0; x < r; x++)
101 for (; x < width / 2; x++) {
102 v += dc[x] - dc[x-r];
103 dc[x-r] = v * dc_factor >> 16;
105 for (; x < (width + r + 1) / 2; x++)
106 dc[x-r] = v * dc_factor >> 16;
107 for (x = -r / 2; x < 0; x++)
111 for (y = 0; y < r; y++)
112 ctx->filter_line(dst + y * dst_linesize, src + y * src_linesize, dc - r / 2, width, thresh, dither[y & 7]);
114 ctx->filter_line(dst + y * dst_linesize, src + y * src_linesize, dc - r / 2, width, thresh, dither[y & 7]);
115 if (++y >= height) break;
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;
121 static av_cold int init(AVFilterContext *ctx, const char *args)
123 GradFunContext *gf = ctx->priv;
128 sscanf(args, "%f:%d", &thresh, &radius);
130 thresh = av_clipf(thresh, 0.51, 255);
131 gf->thresh = (1 << 15) / thresh;
132 gf->radius = av_clip((radius + 1) & ~1, 4, 32);
134 gf->blur_line = ff_gradfun_blur_line_c;
135 gf->filter_line = ff_gradfun_filter_line_c;
138 ff_gradfun_init_x86(gf);
140 av_log(ctx, AV_LOG_VERBOSE, "threshold:%.2f radius:%d\n", thresh, gf->radius);
145 static av_cold void uninit(AVFilterContext *ctx)
147 GradFunContext *gf = ctx->priv;
151 static int query_formats(AVFilterContext *ctx)
153 static const enum PixelFormat pix_fmts[] = {
154 PIX_FMT_YUV410P, PIX_FMT_YUV420P,
155 PIX_FMT_GRAY8, PIX_FMT_NV12,
156 PIX_FMT_NV21, PIX_FMT_YUV444P,
157 PIX_FMT_YUV422P, PIX_FMT_YUV411P,
161 ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
166 static int config_input(AVFilterLink *inlink)
168 GradFunContext *gf = inlink->dst->priv;
169 int hsub = av_pix_fmt_descriptors[inlink->format].log2_chroma_w;
170 int vsub = av_pix_fmt_descriptors[inlink->format].log2_chroma_h;
172 gf->buf = av_mallocz((FFALIGN(inlink->w, 16) * (gf->radius + 1) / 2 + 32) * sizeof(uint16_t));
174 return AVERROR(ENOMEM);
176 gf->chroma_w = -((-inlink->w) >> hsub);
177 gf->chroma_h = -((-inlink->h) >> vsub);
178 gf->chroma_r = av_clip(((((gf->radius >> hsub) + (gf->radius >> vsub)) / 2 ) + 1) & ~1, 4, 32);
183 static int start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
185 AVFilterLink *outlink = inlink->dst->outputs[0];
186 AVFilterBufferRef *outpicref = NULL;
189 if (inpicref->perms & AV_PERM_PRESERVE) {
190 outpicref = ff_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
192 return AVERROR(ENOMEM);
194 avfilter_copy_buffer_ref_props(outpicref, inpicref);
195 outpicref->video->w = outlink->w;
196 outpicref->video->h = outlink->h;
198 outpicref = avfilter_ref_buffer(inpicref, ~0);
200 return AVERROR(ENOMEM);
203 ret = ff_start_frame(outlink, avfilter_ref_buffer(outpicref, ~0));
205 avfilter_unref_bufferp(&outpicref);
209 outlink->out_buf = outpicref;
213 static int null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
218 static void end_frame(AVFilterLink *inlink)
220 GradFunContext *gf = inlink->dst->priv;
221 AVFilterBufferRef *inpic = inlink->cur_buf;
222 AVFilterLink *outlink = inlink->dst->outputs[0];
223 AVFilterBufferRef *outpic = outlink->out_buf;
226 for (p = 0; p < 4 && inpic->data[p]; p++) {
236 if (FFMIN(w, h) > 2 * r)
237 filter(gf, outpic->data[p], inpic->data[p], w, h, outpic->linesize[p], inpic->linesize[p], r);
238 else if (outpic->data[p] != inpic->data[p])
239 av_image_copy_plane(outpic->data[p], outpic->linesize[p], inpic->data[p], inpic->linesize[p], w, h);
242 ff_draw_slice(outlink, 0, inlink->h, 1);
243 ff_end_frame(outlink);
246 AVFilter avfilter_vf_gradfun = {
248 .description = NULL_IF_CONFIG_SMALL("Debands video quickly using gradients."),
249 .priv_size = sizeof(GradFunContext),
252 .query_formats = query_formats,
254 .inputs = (const AVFilterPad[]) {{ .name = "default",
255 .type = AVMEDIA_TYPE_VIDEO,
256 .config_props = config_input,
257 .start_frame = start_frame,
258 .draw_slice = null_draw_slice,
259 .end_frame = end_frame,
260 .min_perms = AV_PERM_READ, },
262 .outputs = (const AVFilterPad[]) {{ .name = "default",
263 .type = AVMEDIA_TYPE_VIDEO, },