/*
* Copyright (c) 2010 Nolan Lum <nol888@gmail.com>
* Copyright (c) 2009 Loren Merritt <lorenm@u.washignton.edu>
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; 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 "gradfun.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, const uint8_t *src, const 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, const uint16_t *buf1, const 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, const 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, void *opaque)
{
GradFunContext *gf = ctx->priv;
float thresh = 1.2;
int radius = 16;
av_unused int cpu_flags = av_get_cpu_flags();
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 && cpu_flags & AV_CPU_FLAG_MMX2)
gf->filter_line = ff_gradfun_filter_line_mmx2;
if (HAVE_SSSE3 && cpu_flags & AV_CPU_FLAG_SSSE3)
gf->filter_line = ff_gradfun_filter_line_ssse3;
if (HAVE_SSE && cpu_flags & AV_CPU_FLAG_SSE2)
gf->blur_line = ff_gradfun_blur_line_sse2;
av_log(ctx, AV_LOG_INFO, "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
};
avfilter_set_common_pixel_formats(ctx, avfilter_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 void start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
{
AVFilterLink *outlink = inlink->dst->outputs[0];
AVFilterBufferRef *outpicref;
if (inpicref->perms & AV_PERM_PRESERVE) {
outpicref = avfilter_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
avfilter_copy_buffer_ref_props(outpicref, inpicref);
outpicref->video->w = outlink->w;
outpicref->video->h = outlink->h;
} else
outpicref = inpicref;
outlink->out_buf = outpicref;
avfilter_start_frame(outlink, avfilter_ref_buffer(outpicref, ~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);
}
avfilter_draw_slice(outlink, 0, inlink->h, 1);
avfilter_end_frame(outlink);
avfilter_unref_buffer(inpic);
if (outpic != inpic)
avfilter_unref_buffer(outpic);
}
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}},
};