/* * Copyright (c) 2010 Nolan Lum * Copyright (c) 2009 Loren Merritt * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * gradfun debanding filter, ported from MPlayer * libmpcodecs/vf_gradfun.c * * Apply a boxblur debanding algorithm (based on the gradfun2db * Avisynth filter by prunedtree). * Foreach pixel, if it's within threshold of the blurred value, make it closer. * So now we have a smoothed and higher bitdepth version of all the shallow * gradients, while leaving detailed areas untouched. * Dither it back to 8bit. */ #include "libavutil/imgutils.h" #include "libavutil/cpu.h" #include "libavutil/pixdesc.h" #include "avfilter.h" #include "formats.h" #include "gradfun.h" #include "internal.h" #include "video.h" DECLARE_ALIGNED(16, static const uint16_t, dither)[8][8] = { {0x00,0x60,0x18,0x78,0x06,0x66,0x1E,0x7E}, {0x40,0x20,0x58,0x38,0x46,0x26,0x5E,0x3E}, {0x10,0x70,0x08,0x68,0x16,0x76,0x0E,0x6E}, {0x50,0x30,0x48,0x28,0x56,0x36,0x4E,0x2E}, {0x04,0x64,0x1C,0x7C,0x02,0x62,0x1A,0x7A}, {0x44,0x24,0x5C,0x3C,0x42,0x22,0x5A,0x3A}, {0x14,0x74,0x0C,0x6C,0x12,0x72,0x0A,0x6A}, {0x54,0x34,0x4C,0x2C,0x52,0x32,0x4A,0x2A}, }; void ff_gradfun_filter_line_c(uint8_t *dst, uint8_t *src, uint16_t *dc, int width, int thresh, const uint16_t *dithers) { int x; for (x = 0; x < width; x++, dc += x & 1) { int pix = src[x] << 7; int delta = dc[0] - pix; int m = abs(delta) * thresh >> 16; m = FFMAX(0, 127 - m); m = m * m * delta >> 14; pix += m + dithers[x & 7]; dst[x] = av_clip_uint8(pix >> 7); } } void ff_gradfun_blur_line_c(uint16_t *dc, uint16_t *buf, uint16_t *buf1, uint8_t *src, int src_linesize, int width) { int x, v, old; for (x = 0; x < width; x++) { v = buf1[x] + src[2 * x] + src[2 * x + 1] + src[2 * x + src_linesize] + src[2 * x + 1 + src_linesize]; old = buf[x]; buf[x] = v; dc[x] = v - old; } } static void filter(GradFunContext *ctx, uint8_t *dst, uint8_t *src, int width, int height, int dst_linesize, int src_linesize, int r) { int bstride = FFALIGN(width, 16) / 2; int y; uint32_t dc_factor = (1 << 21) / (r * r); uint16_t *dc = ctx->buf + 16; uint16_t *buf = ctx->buf + bstride + 32; int thresh = ctx->thresh; memset(dc, 0, (bstride + 16) * sizeof(*buf)); for (y = 0; y < r; y++) ctx->blur_line(dc, buf + y * bstride, buf + (y - 1) * bstride, src + 2 * y * src_linesize, src_linesize, width / 2); for (;;) { if (y < height - r) { int mod = ((y + r) / 2) % r; uint16_t *buf0 = buf + mod * bstride; uint16_t *buf1 = buf + (mod ? mod - 1 : r - 1) * bstride; int x, v; ctx->blur_line(dc, buf0, buf1, src + (y + r) * src_linesize, src_linesize, width / 2); for (x = v = 0; x < r; x++) v += dc[x]; for (; x < width / 2; x++) { v += dc[x] - dc[x-r]; dc[x-r] = v * dc_factor >> 16; } for (; x < (width + r + 1) / 2; x++) dc[x-r] = v * dc_factor >> 16; for (x = -r / 2; x < 0; x++) dc[x] = dc[0]; } if (y == r) { for (y = 0; y < r; y++) ctx->filter_line(dst + y * dst_linesize, src + y * src_linesize, dc - r / 2, width, thresh, dither[y & 7]); } ctx->filter_line(dst + y * dst_linesize, src + y * src_linesize, dc - r / 2, width, thresh, dither[y & 7]); if (++y >= height) break; ctx->filter_line(dst + y * dst_linesize, src + y * src_linesize, dc - r / 2, width, thresh, dither[y & 7]); if (++y >= height) break; } } static av_cold int init(AVFilterContext *ctx, const char *args) { GradFunContext *gf = ctx->priv; float thresh = 1.2; int radius = 16; if (args) sscanf(args, "%f:%d", &thresh, &radius); thresh = av_clipf(thresh, 0.51, 255); gf->thresh = (1 << 15) / thresh; gf->radius = av_clip((radius + 1) & ~1, 4, 32); gf->blur_line = ff_gradfun_blur_line_c; gf->filter_line = ff_gradfun_filter_line_c; if (HAVE_MMX) ff_gradfun_init_x86(gf); av_log(ctx, AV_LOG_VERBOSE, "threshold:%.2f radius:%d\n", thresh, gf->radius); return 0; } static av_cold void uninit(AVFilterContext *ctx) { GradFunContext *gf = ctx->priv; av_freep(&gf->buf); } static int query_formats(AVFilterContext *ctx) { static const enum PixelFormat pix_fmts[] = { PIX_FMT_YUV410P, PIX_FMT_YUV420P, PIX_FMT_GRAY8, PIX_FMT_NV12, PIX_FMT_NV21, PIX_FMT_YUV444P, PIX_FMT_YUV422P, PIX_FMT_YUV411P, PIX_FMT_NONE }; ff_set_common_formats(ctx, ff_make_format_list(pix_fmts)); return 0; } static int config_input(AVFilterLink *inlink) { GradFunContext *gf = inlink->dst->priv; int hsub = av_pix_fmt_descriptors[inlink->format].log2_chroma_w; int vsub = av_pix_fmt_descriptors[inlink->format].log2_chroma_h; gf->buf = av_mallocz((FFALIGN(inlink->w, 16) * (gf->radius + 1) / 2 + 32) * sizeof(uint16_t)); if (!gf->buf) return AVERROR(ENOMEM); gf->chroma_w = -((-inlink->w) >> hsub); gf->chroma_h = -((-inlink->h) >> vsub); gf->chroma_r = av_clip(((((gf->radius >> hsub) + (gf->radius >> vsub)) / 2 ) + 1) & ~1, 4, 32); return 0; } static int start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref) { AVFilterLink *outlink = inlink->dst->outputs[0]; AVFilterBufferRef *outpicref = NULL; int ret = 0; if (inpicref->perms & AV_PERM_PRESERVE) { outpicref = ff_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h); if (!outpicref) return AVERROR(ENOMEM); avfilter_copy_buffer_ref_props(outpicref, inpicref); outpicref->video->w = outlink->w; outpicref->video->h = outlink->h; } else { outpicref = avfilter_ref_buffer(inpicref, ~0); if (!outpicref) return AVERROR(ENOMEM); } ret = ff_start_frame(outlink, avfilter_ref_buffer(outpicref, ~0)); if (ret < 0) { avfilter_unref_bufferp(&outpicref); return ret; } outlink->out_buf = outpicref; return 0; } static void null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir) { } static void end_frame(AVFilterLink *inlink) { GradFunContext *gf = inlink->dst->priv; AVFilterBufferRef *inpic = inlink->cur_buf; AVFilterLink *outlink = inlink->dst->outputs[0]; AVFilterBufferRef *outpic = outlink->out_buf; int p; for (p = 0; p < 4 && inpic->data[p]; p++) { int w = inlink->w; int h = inlink->h; int r = gf->radius; if (p) { w = gf->chroma_w; h = gf->chroma_h; r = gf->chroma_r; } if (FFMIN(w, h) > 2 * r) filter(gf, outpic->data[p], inpic->data[p], w, h, outpic->linesize[p], inpic->linesize[p], r); else if (outpic->data[p] != inpic->data[p]) av_image_copy_plane(outpic->data[p], outpic->linesize[p], inpic->data[p], inpic->linesize[p], w, h); } ff_draw_slice(outlink, 0, inlink->h, 1); ff_end_frame(outlink); } AVFilter avfilter_vf_gradfun = { .name = "gradfun", .description = NULL_IF_CONFIG_SMALL("Debands video quickly using gradients."), .priv_size = sizeof(GradFunContext), .init = init, .uninit = uninit, .query_formats = query_formats, .inputs = (const AVFilterPad[]) {{ .name = "default", .type = AVMEDIA_TYPE_VIDEO, .config_props = config_input, .start_frame = start_frame, .draw_slice = null_draw_slice, .end_frame = end_frame, .min_perms = AV_PERM_READ, }, { .name = NULL}}, .outputs = (const AVFilterPad[]) {{ .name = "default", .type = AVMEDIA_TYPE_VIDEO, }, { .name = NULL}}, };