libavfilter/vf_gradfun.c

   1 /*
   2  * Copyright (c) 2010 Nolan Lum <nol888@gmail.com>
   3  * Copyright (c) 2009 Loren Merritt <lorenm@u.washignton.edu>
   4  *
   5  * This file is part of Libav.
   6  *
   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.
  11  *
  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.
  16  *
  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
  20  */
  21
  22 /**
  23  * @file
  24  * gradfun debanding filter, ported from MPlayer
  25  * libmpcodecs/vf_gradfun.c
  26  *
  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.
  33  */
  34
  35 #include "libavutil/imgutils.h"
  36 #include "libavutil/common.h"
  37 #include "libavutil/cpu.h"
  38 #include "libavutil/pixdesc.h"
  39 #include "avfilter.h"
  40 #include "formats.h"
  41 #include "gradfun.h"
  42 #include "internal.h"
  43 #include "video.h"
  44
  45 DECLARE_ALIGNED(16, static const uint16_t, dither)[8][8] = {
  46     {0x00,0x60,0x18,0x78,0x06,0x66,0x1E,0x7E},
  47     {0x40,0x20,0x58,0x38,0x46,0x26,0x5E,0x3E},
  48     {0x10,0x70,0x08,0x68,0x16,0x76,0x0E,0x6E},
  49     {0x50,0x30,0x48,0x28,0x56,0x36,0x4E,0x2E},
  50     {0x04,0x64,0x1C,0x7C,0x02,0x62,0x1A,0x7A},
  51     {0x44,0x24,0x5C,0x3C,0x42,0x22,0x5A,0x3A},
  52     {0x14,0x74,0x0C,0x6C,0x12,0x72,0x0A,0x6A},
  53     {0x54,0x34,0x4C,0x2C,0x52,0x32,0x4A,0x2A},
  54 };
  55
  56 void ff_gradfun_filter_line_c(uint8_t *dst, uint8_t *src, uint16_t *dc, int width, int thresh, const uint16_t *dithers)
  57 {
  58     int x;
  59     for (x = 0; x < width; x++, dc += x & 1) {
  60         int pix = src[x] << 7;
  61         int delta = dc[0] - pix;
  62         int m = abs(delta) * thresh >> 16;
  63         m = FFMAX(0, 127 - m);
  64         m = m * m * delta >> 14;
  65         pix += m + dithers[x & 7];
  66         dst[x] = av_clip_uint8(pix >> 7);
  67     }
  68 }
  69
  70 void ff_gradfun_blur_line_c(uint16_t *dc, uint16_t *buf, uint16_t *buf1, uint8_t *src, int src_linesize, int width)
  71 {
  72     int x, v, old;
  73     for (x = 0; x < width; x++) {
  74         v = buf1[x] + src[2 * x] + src[2 * x + 1] + src[2 * x + src_linesize] + src[2 * x + 1 + src_linesize];
  75         old = buf[x];
  76         buf[x] = v;
  77         dc[x] = v - old;
  78     }
  79 }
  80
  81 static void filter(GradFunContext *ctx, uint8_t *dst, uint8_t *src, int width, int height, int dst_linesize, int src_linesize, int r)
  82 {
  83     int bstride = FFALIGN(width, 16) / 2;
  84     int y;
  85     uint32_t dc_factor = (1 << 21) / (r * r);
  86     uint16_t *dc = ctx->buf + 16;
  87     uint16_t *buf = ctx->buf + bstride + 32;
  88     int thresh = ctx->thresh;
  89
  90     memset(dc, 0, (bstride + 16) * sizeof(*buf));
  91     for (y = 0; y < r; y++)
  92         ctx->blur_line(dc, buf + y * bstride, buf + (y - 1) * bstride, src + 2 * y * src_linesize, src_linesize, width / 2);
  93     for (;;) {
  94         if (y < height - r) {
  95             int mod = ((y + r) / 2) % r;
  96             uint16_t *buf0 = buf + mod * bstride;
  97             uint16_t *buf1 = buf + (mod ? mod - 1 : r - 1) * bstride;
  98             int x, v;
  99             ctx->blur_line(dc, buf0, buf1, src + (y + r) * src_linesize, src_linesize, width / 2);
 100             for (x = v = 0; x < r; x++)
 101                 v += dc[x];
 102             for (; x < width / 2; x++) {
 103                 v += dc[x] - dc[x-r];
 104                 dc[x-r] = v * dc_factor >> 16;
 105             }
 106             for (; x < (width + r + 1) / 2; x++)
 107                 dc[x-r] = v * dc_factor >> 16;
 108             for (x = -r / 2; x < 0; x++)
 109                 dc[x] = dc[0];
 110         }
 111         if (y == r) {
 112             for (y = 0; y < r; y++)
 113                 ctx->filter_line(dst + y * dst_linesize, src + y * src_linesize, dc - r / 2, width, thresh, dither[y & 7]);
 114         }
 115         ctx->filter_line(dst + y * dst_linesize, src + y * src_linesize, dc - r / 2, width, thresh, dither[y & 7]);
 116         if (++y >= height) break;
 117         ctx->filter_line(dst + y * dst_linesize, src + y * src_linesize, dc - r / 2, width, thresh, dither[y & 7]);
 118         if (++y >= height) break;
 119     }
 120 }
 121
 122 static av_cold int init(AVFilterContext *ctx, const char *args)
 123 {
 124     GradFunContext *gf = ctx->priv;
 125     float thresh = 1.2;
 126     int radius = 16;
 127
 128     if (args)
 129         sscanf(args, "%f:%d", &thresh, &radius);
 130
 131     thresh = av_clipf(thresh, 0.51, 255);
 132     gf->thresh = (1 << 15) / thresh;
 133     gf->radius = av_clip((radius + 1) & ~1, 4, 32);
 134
 135     gf->blur_line = ff_gradfun_blur_line_c;
 136     gf->filter_line = ff_gradfun_filter_line_c;
 137
 138     if (ARCH_X86)
 139         ff_gradfun_init_x86(gf);
 140
 141     av_log(ctx, AV_LOG_VERBOSE, "threshold:%.2f radius:%d\n", thresh, gf->radius);
 142
 143     return 0;
 144 }
 145
 146 static av_cold void uninit(AVFilterContext *ctx)
 147 {
 148     GradFunContext *gf = ctx->priv;
 149     av_freep(&gf->buf);
 150 }
 151
 152 static int query_formats(AVFilterContext *ctx)
 153 {
 154     static const enum AVPixelFormat pix_fmts[] = {
 155         AV_PIX_FMT_YUV410P,            AV_PIX_FMT_YUV420P,
 156         AV_PIX_FMT_GRAY8,              AV_PIX_FMT_NV12,
 157         AV_PIX_FMT_NV21,               AV_PIX_FMT_YUV444P,
 158         AV_PIX_FMT_YUV422P,            AV_PIX_FMT_YUV411P,
 159         AV_PIX_FMT_NONE
 160     };
 161
 162     ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
 163
 164     return 0;
 165 }
 166
 167 static int config_input(AVFilterLink *inlink)
 168 {
 169     GradFunContext *gf = inlink->dst->priv;
 170     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
 171     int hsub = desc->log2_chroma_w;
 172     int vsub = desc->log2_chroma_h;
 173
 174     gf->buf = av_mallocz((FFALIGN(inlink->w, 16) * (gf->radius + 1) / 2 + 32) * sizeof(uint16_t));
 175     if (!gf->buf)
 176         return AVERROR(ENOMEM);
 177
 178     gf->chroma_w = -((-inlink->w) >> hsub);
 179     gf->chroma_h = -((-inlink->h) >> vsub);
 180     gf->chroma_r = av_clip(((((gf->radius >> hsub) + (gf->radius >> vsub)) / 2 ) + 1) & ~1, 4, 32);
 181
 182     return 0;
 183 }
 184
 185 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 186 {
 187     GradFunContext *gf = inlink->dst->priv;
 188     AVFilterLink *outlink = inlink->dst->outputs[0];
 189     AVFrame *out;
 190     int p, direct;
 191
 192     if (av_frame_is_writable(in)) {
 193         direct = 1;
 194         out = in;
 195     } else {
 196         out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
 197         if (!out) {
 198             av_frame_free(&in);
 199             return AVERROR(ENOMEM);
 200         }
 201
 202         av_frame_copy_props(out, in);
 203         out->width  = outlink->w;
 204         out->height = outlink->h;
 205     }
 206
 207     for (p = 0; p < 4 && in->data[p]; p++) {
 208         int w = inlink->w;
 209         int h = inlink->h;
 210         int r = gf->radius;
 211         if (p) {
 212             w = gf->chroma_w;
 213             h = gf->chroma_h;
 214             r = gf->chroma_r;
 215         }
 216
 217         if (FFMIN(w, h) > 2 * r)
 218             filter(gf, out->data[p], in->data[p], w, h, out->linesize[p], in->linesize[p], r);
 219         else if (out->data[p] != in->data[p])
 220             av_image_copy_plane(out->data[p], out->linesize[p], in->data[p], in->linesize[p], w, h);
 221     }
 222
 223     if (!direct)
 224         av_frame_free(&in);
 225
 226     return ff_filter_frame(outlink, out);
 227 }
 228
 229 static const AVFilterPad avfilter_vf_gradfun_inputs[] = {
 230     {
 231         .name         = "default",
 232         .type         = AVMEDIA_TYPE_VIDEO,
 233         .config_props = config_input,
 234         .filter_frame = filter_frame,
 235     },
 236     { NULL }
 237 };
 238
 239 static const AVFilterPad avfilter_vf_gradfun_outputs[] = {
 240     {
 241         .name = "default",
 242         .type = AVMEDIA_TYPE_VIDEO,
 243     },
 244     { NULL }
 245 };
 246
 247 AVFilter avfilter_vf_gradfun = {
 248     .name          = "gradfun",
 249     .description   = NULL_IF_CONFIG_SMALL("Debands video quickly using gradients."),
 250     .priv_size     = sizeof(GradFunContext),
 251     .init          = init,
 252     .uninit        = uninit,
 253     .query_formats = query_formats,
 254
 255     .inputs    = avfilter_vf_gradfun_inputs,
 256     .outputs   = avfilter_vf_gradfun_outputs,
 257 };