[FFmpeg-devel] [PATCH] lavfi: add xbr filter
Stefano Sabatini
stefasab at gmail.com
Fri Oct 31 14:01:37 CET 2014
On date Friday 2014-10-31 01:36:46 +0530, arwa arif encoded:
[...]
> From b9b56b594f856fef8b113b283df2d2045e8357f7 Mon Sep 17 00:00:00 2001
> From: Arwa Arif <arwaarif1994 at gmail.com>
> Date: Thu, 30 Oct 2014 22:06:20 +0530
> Subject: [PATCH] [PATCH]lvafi: add xbr filter
typo: lavfi:
>
> ---
> doc/filters.texi | 5 +
> libavfilter/Makefile | 1 +
> libavfilter/allfilters.c | 1 +
> libavfilter/vf_xbr.c | 319 ++++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 326 insertions(+)
> create mode 100644 libavfilter/vf_xbr.c
>
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 7be29de..2905e5d 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -9163,6 +9163,11 @@ Only deinterlace frames marked as interlaced.
> Default value is @samp{all}.
> @end table
>
> + at section xbr
> +Apply high-quality magnification filter which is designed for pixel art. It follows a set
> +of edge-detection rules @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
> +This filter was originally created by Hyllian.
> +
> @anchor{yadif}
> @section yadif
>
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index 6d868e7..2c56e38 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -198,6 +198,7 @@ OBJS-$(CONFIG_VIDSTABDETECT_FILTER) += vidstabutils.o vf_vidstabdetect.
> OBJS-$(CONFIG_VIDSTABTRANSFORM_FILTER) += vidstabutils.o vf_vidstabtransform.o
> OBJS-$(CONFIG_VIGNETTE_FILTER) += vf_vignette.o
> OBJS-$(CONFIG_W3FDIF_FILTER) += vf_w3fdif.o
> +OBJS-$(CONFIG_XBR_FILTER) += vf_xbr.o
> OBJS-$(CONFIG_YADIF_FILTER) += vf_yadif.o
> OBJS-$(CONFIG_ZMQ_FILTER) += f_zmq.o
> OBJS-$(CONFIG_ZOOMPAN_FILTER) += vf_zoompan.o
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index d88a9ad..2352d44 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -213,6 +213,7 @@ void avfilter_register_all(void)
> REGISTER_FILTER(VIDSTABTRANSFORM, vidstabtransform, vf);
> REGISTER_FILTER(VIGNETTE, vignette, vf);
> REGISTER_FILTER(W3FDIF, w3fdif, vf);
> + REGISTER_FILTER(XBR, xbr, vf);
> REGISTER_FILTER(YADIF, yadif, vf);
> REGISTER_FILTER(ZMQ, zmq, vf);
> REGISTER_FILTER(ZOOMPAN, zoompan, vf);
> diff --git a/libavfilter/vf_xbr.c b/libavfilter/vf_xbr.c
> new file mode 100644
> index 0000000..1a828d8
> --- /dev/null
> +++ b/libavfilter/vf_xbr.c
> @@ -0,0 +1,319 @@
> +/*
> + * This file is part of FFmpeg.
> + *
> + * Copyright (c) 2014 Arwa Arif <arwaarif1994 at gmail.com>
> + *
> + * 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
> + * XBR Filter is used for depixelization of image.
> + * This is based on Hyllian's 2xBR shader.
> + * 2xBR Filter v0.2.5
> + * @see : http://www.libretro.com/forums/viewtopic.php?f=6&t=134
> + * Future work : To implement x3 and x4 scale, and threading.
> + */
> +
> +#include "libavutil/opt.h"
> +#include "libavutil/avassert.h"
> +#include "libavutil/pixdesc.h"
> +#include "internal.h"
> +
> +typedef struct {
> + uint32_t rgbtoyuv[1<<24];
> +} xBRContext;
> +
> +/**
> +* Calculates the weight of difference of the pixels, by transforming these
> +* pixels into their Y'UV parts. It then uses the threshold used by HQx filters:
> +* 48*Y + 7*U + 6*V, to give it those smooth looking edges.
> +**/
> +static int d(AVFrame *in, int x1, int y1, int x2, int y2, const uint32_t *r2y)
nit: use a more significant name, for example compute_diff() or diff()
> +{
> +
> +#define YMASK 0xff0000
> +#define UMASK 0x00ff00
> +#define VMASK 0x0000ff
> +
> + int r1 = *(in->data[0] + y1 * in->linesize[0] + x1*3);
> + int g1 = *(in->data[0] + y1 * in->linesize[0] + x1*3 + 1);
> + int b1 = *(in->data[0] + y1 * in->linesize[0] + x1*3 + 2);
> +
> + int r2 = *(in->data[0] + y2 * in->linesize[0] + x2*3);
> + int g2 = *(in->data[0] + y2 * in->linesize[0] + x2*3 + 1);
> + int b2 = *(in->data[0] + y2 * in->linesize[0] + x2*3 + 2);
> +
> + uint32_t c1 = r1 | g1<<8 | b1<<16 ;
> + uint32_t c2 = r2 | g2<<8 | b2<<16 ;
> +
> + uint32_t yuv1 = r2y[c1 & 0xffffff];
> + uint32_t yuv2 = r2y[c2 & 0xffffff];
is the 0xffffff mask required?
> +
> + return abs((yuv1 & YMASK) - (yuv2 & YMASK)) > (48 << 16) ||
> + abs((yuv1 & UMASK) - (yuv2 & UMASK)) > ( 7 << 8) ||
> + abs((yuv1 & VMASK) - (yuv2 & VMASK)) > ( 6 << 0);
> +}
> +
> +/**
> +* Mixes a pixel A, with pixel B, with B's transparency set to 'a'
> +* In other words, A is a solid color (bottom) and B is a transparent color (top)
> +**/
> +static int mix(AVFrame *in, int x1, int y1, int x2, int y2, int a, int color)
> +{
> + int col1,col2;
> + col1 = *(in->data[0] + y1 * in->linesize[0] + x1*3 + color);
> + col2 = *(in->data[0] + y2 * in->linesize[0] + x2*3 + color);
> +
> + return (a*col2 + (2-a)*col1)/2;
> +};
> +
> +/**
> +* Fills the output matrix
> +**/
> +static void fill(AVFrame *in, AVFrame *out, int u, int v, int x, int y, int mode, int new_x, int new_y)
> +{
> + int r,g,b;
> + /*mix colors if they are not on boundary*/
> + if (mode!=0 && u>=0 && v>=0 && u<in->width && v<in->height) {
> +
> + r = mix(in, u, v, x, y, 1, 0);
> + g = mix(in, u, v, x, y, 1, 1);
> + b = mix(in, u, v, x, y, 1, 2);
> +
> + } else {
> +
> + r = *(in->data[0] + y*in->linesize[0] + x*3);
> + g = *(in->data[0] + y*in->linesize[0] + x*3 + 1);
> + b = *(in->data[0] + y*in->linesize[0] + x*3 + 2);
> + }
> +
> + /*Insert blended color into scaledImageData*/
scaledImageData => output image
> + *(out->data[0] + (new_y)*out->linesize[0] + (new_x)*3) = r;
> + *(out->data[0] + (new_y)*out->linesize[0] + (new_x)*3 + 1) = g;
> + *(out->data[0] + (new_y)*out->linesize[0] + (new_x)*3 + 2) = b;
nit++: probably unrelevant, but you can factorize like this:
uint8_t *outp = out->data[0] + new_y*out->linesize[0] + new_x*3;
outp[0] = r;
outp[1] = g;
outp[2] = b;
same above
> + return;
> +}
> +
> +/**
> +* Applies the xBR filter rules.
> +**/
> +static void apply_edge_detection_rules(AVFrame *in, AVFrame *out, int x, int y, const uint32_t *r2y)
> +{
> + /* Matrix: (E is 0,0 i.e: current pixel)
> + -2 | -1| 0| +1| +2 (x)
> + ______________________________
> + -2 | [A1][B1][C1]
> + -1 | [A0][ A][ B][ C][C4]
> + 0 | [D0][ D][ E][ F][F4]
> + +1 | [G0][ G][ H][ I][I4]
> + +2 | [G5][H5][I5]
> + |(y)|
> + */
> +
> + /*Cached Pixel Weight Difference*/
> + int d_E_D = d(in, x, y, x-1, y, r2y);
> + int d_E_B = d(in, x, y, x, y-1, r2y);
> + int d_E_F = d(in, x, y, x+1, y, r2y);
> + int d_E_H = d(in, x, y, x, y+1, r2y);
> + int d_E_G = d(in, x, y, x-1, y+1, r2y);
> + int d_E_C = d(in, x, y, x+1, y-1, r2y);
> + int d_A_D0 = d(in, x-1, y-1, x-2, y, r2y);
> + int d_A_B1 = d(in, x-1, y-1, x, y-2, r2y);
> + int d_D_B = d(in, x-1, y, x, y-1, r2y);
> + int d_D_H = d(in, x-1, y, x, y+1, r2y);
> + int d_D_A0 = d(in, x-1, y, x-2, y-1, r2y);
> + int d_B_F = d(in, x, y-1, x+1, y, r2y);
> + int d_B_A1 = d(in, x, y-1, x-1, y-2, r2y);
> + int d_E_A = d(in, x, y, x-1, y-1, r2y);
> + int d_E_I = d(in, x, y, x+1, y+1, r2y);
> + int d_C_F4 = d(in, x+1, y-1, x+2, y, r2y);
> + int d_C_B1 = d(in, x+1, y-1, x, y-2, r2y);
> + int d_F_H = d(in, x+1, y, x, y+1, r2y);
> + int d_F_C4 = d(in, x+1, y, x+2, y-1, r2y);
> + int d_B_C1 = d(in, x, y-1, x+1, y-2, r2y);
> + int d_G_D0 = d(in, x-1, y+1, x-2, y, r2y);
> + int d_G_H5 = d(in, x-1, y+1, x, y+2, r2y);
> + int d_H_G5 = d(in, x, y+1, x-1, y+2, r2y);
> + int d_D_G0 = d(in, x-1, y, x-2, y+1, r2y);
> + int d_I_F4 = d(in, x+1, y+1, x+2, y, r2y);
> + int d_I_H5 = d(in, x+1, y+1, x, y+2, r2y);
> + int d_H_I5 = d(in, x, y+1, x+1, y+2, r2y);
> + int d_H_I4 = d(in, x, y+1, x+2, y+1, r2y);
This is accessing out-of-image pixels at the border. You need probably
to normalize the values with something like this:
int d_E_D = d(in, x, y, FFMAX(x-1, 0), y, r2y);
int d_E_B = d(in, x, y, x, FFMAX(y-1, 0), r2y);
int d_E_F = d(in, x, y, FFMIN(x+1, w-1), y, r2y);
...
> +
> + /**
> + * Note: On reading edge detection rules
> + *
> + * Each edge rule is an if..else statement, everytime on else, the
> + * current pixel color pointed to by matrix[0] is used to color it's edge.
its edge
> + *
> + * Each if statement checks wether the sum of weight difference on the left is
> + * lesser than that of the right weight differece.
difference
(please never disregard my previous comments, I already pointed out
those typos and having to repeat myself is annoying)
> + */
> +
> + /**
> + * Top Left Edge Detection Rule
> + **/
> + if ((d_E_G+d_E_C+d_A_D0+d_A_B1+(4*d_D_B)) < (d_D_H+d_D_A0+d_B_F+d_B_A1+(4*d_E_A))) {
> + // Figure what color to blend with current pixel -->E
please remove these comments as they are confusing (or improve them, I
cannot figure out what -->E means)
> + if (d_E_D <= d_E_B)
> + fill(in, out, x-1, y, x, y, 1, x*2, y*2);
> + else
> + fill(in, out, x, y-1, x, y, 1, x*2, y*2);
> + } else {
> + /*Insert current pixel color into output frame*/
> + fill(in, out, x, y, x, y, 0, x*2, y*2);
> + }
> + /**
> + * Top Right Edge Detection Rule
> + **/
> + if ((d_E_I+d_E_A+d_C_F4+d_C_B1+(4*d_B_F)) < (d_F_H+d_F_C4+d_D_B+d_B_C1+(4*d_E_C))) {
> + // Figure what color to blend with current pixel --> E
> + if (d_E_B <= d_E_F)
> + fill(in, out, x, y-1, x, y, 1, (x*2)+1, y*2);
> + else
> + fill(in, out, x+1, y, x, y, 1, (x*2)+1, y*2);
> + } else {
> + /*Insert current pixel color into output frame*/
> + fill(in, out, x, y, x, y, 0, (x*2)+1, y*2);
> + }
> +
> + /**
> + * Bottom Left Edge Detection Rule
> + **/
> + if ((d_E_A+d_E_I+d_G_D0+d_G_H5+(4*d_D_H)) < (d_D_B+d_D_G0+d_F_H+d_H_G5+(4*d_E_G))) {
> + // Figure what color to blend with current pixel --> E
> + if (d_E_D <= d_E_H)
> + fill(in, out, x-1, y, x, y, 1, x*2, (y*2)+1);
> + else
> + fill(in, out, x, y+1, x, y, 1, x*2, (y*2)+1);
> +
> + } else {
> + /*Insert current pixel color into output frame*/
> + fill(in, out, x, y, x, y, 0, x*2, (y*2)+1);
> + }
> +
> + /**
> + * Bottom Right Edge Detection Rule
> + **/
> + if ((d_E_C+d_E_G+d_I_F4+d_I_H5+(4*d_F_H)) < (d_D_H+d_H_I5+d_H_I4+d_B_F+(4*d_E_I))) {
> + // Figure what color to blend with current pixel --> E
> + if (d_E_F <= d_E_H)
> + fill(in, out, x+1, y, x, y, 1, (x*2)+1, (y*2)+1);
> + else
> + fill(in, out, x, y+1, x, y, 1, (x*2)+1, (y*2)+1);
> +
> + } else {
> + /*Insert current pixel color into output frame*/
> + fill(in, out, x, y, x, y, 0, (x*2)+1, (y*2)+1);
> + }
this could be factorized through a macro. Feel free to discard this
comment though.
> +}
> +
> +static int config_output(AVFilterLink *outlink)
> +{
> + AVFilterContext *ctx = outlink->src;
> + AVFilterLink *inlink = ctx->inputs[0];
> +
> + outlink->w = inlink->w * 2 ;
> + outlink->h = inlink->h * 2 ;
nit:
outlink->h = inlink->h * 2;
> + return 0;
> +}
> +
> +static int query_formats(AVFilterContext *ctx)
> +{
> + static const enum AVPixelFormat pix_fmts[] = {
> + AV_PIX_FMT_RGB24, AV_PIX_FMT_BGR24,AV_PIX_FMT_NONE,
> + };
> +
> + ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
> + return 0;
> +}
> +
> +static int filter_frame(AVFilterLink *inlink, AVFrame *in)
> +{
> + AVFilterContext *ctx = inlink->dst;
> + AVFilterLink *outlink = ctx->outputs[0];
> + int i,j;
> + xBRContext *xBR = ctx->priv;
> + const uint32_t *r2y = xBR->rgbtoyuv;
> + AVFrame *out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
> + if (!out) {
> + av_frame_free(&in);
> + return AVERROR(ENOMEM);
> + }
> +
> + av_frame_copy_props(out, in);
> + for (i=0; i<inlink->w; i++)
spaces increase readability. The usual FFmpeg style is:
for (i = 0; i < inlink->w; i++)
> + for (j=0; j<inlink->h; j++)
> + apply_edge_detection_rules(in, out, i, j, r2y);
tab
> +
> + out->width = outlink->w;
> + out->height = outlink->h;
> +
> + av_frame_free(&in);
> + return ff_filter_frame(outlink, out);
> +}
> +
> +static int init(AVFilterContext *ctx)
static av_cold int init(AVFilterContext *ctx)
> +{
> + xBRContext *xbr = ctx->priv;
> + uint32_t c;
> + int bg, rg, g;
> +
> + for (bg=-255; bg<256; bg++) {
> + for (rg=-255; rg<256; rg++) {
> + const uint32_t u = (uint32_t)((-169*rg + 500*bg)/1000) + 128;
> + const uint32_t v = (uint32_t)(( 500*rg - 81*bg)/1000) + 128;
> + int startg = FFMAX3(-bg, -rg, 0);
> + int endg = FFMIN3(255-bg, 255-rg, 255);
> + uint32_t y = (uint32_t)(( 299*rg + 1000*startg + 114*bg)/1000);
> + c = bg + (rg<<16) + 0x010101 * startg;
> + for (g = startg; g <= endg; g++) {
> + xbr->rgbtoyuv[c] = ((y++) << 16) + (u << 8) + v;
> + c+= 0x010101;
> + }
> + }
> + }
> + return 0;
> +}
> +
> +static const AVFilterPad xbr_inputs[] = {
> + {
> + .name = "default",
> + .type = AVMEDIA_TYPE_VIDEO,
> + .filter_frame = filter_frame,
> + },
> + { NULL }
> +};
> +
> +static const AVFilterPad xbr_outputs[] = {
> + {
> + .name = "default",
> + .type = AVMEDIA_TYPE_VIDEO,
> + .config_props = config_output,
> + },
> + { NULL }
> +};
> +
> +AVFilter ff_vf_xbr = {
> + .name = "xbr",
> + .description = NULL_IF_CONFIG_SMALL("Scale the input by 2 using xbr algorithm."),
> + .priv_size = sizeof(xBRContext),
> + .inputs = xbr_inputs,
> + .outputs = xbr_outputs,
> + .query_formats = query_formats,
> + .init = init,
> +};
I'd say the patch looks good otherwise.
--
FFmpeg = Frenzy Fundamentalist Multipurpose Portentous Elastic Goblin
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