Add scale filter.
[libav.git] / libavfilter / vf_scale.c
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1/*
2 * copyright (c) 2007 Bobby Bingham
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21/**
22 * @file libavfilter/vf_scale.c
23 * scale video filter
24 */
25
26#include "avfilter.h"
27#include "libswscale/swscale.h"
28
29typedef struct {
30 struct SwsContext *sws; ///< software scaler context
31
32 /**
33 * New dimensions. Special values are:
34 * 0 = original width/height
35 * -1 = keep original aspect
36 */
37 int w, h;
38
39 int hsub, vsub; ///< chroma subsampling
40 int slice_y; ///< top of current output slice
41 int slice_dir; ///< detected slice direction order for the current frame
42 int input_is_pal; ///< set to 1 if the input format is paletted
43} ScaleContext;
44
45static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
46{
47 ScaleContext *scale = ctx->priv;
48
49 if (args)
50 sscanf(args, "%d:%d", &scale->w, &scale->h);
51
52 /* sanity check params */
53 if (scale->w < -1 || scale->h < -1) {
54 av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n");
55 return -1;
56 }
57 if (scale->w == -1 && scale->h == -1)
58 scale->w = scale->h = 0;
59
60 return 0;
61}
62
63static av_cold void uninit(AVFilterContext *ctx)
64{
65 ScaleContext *scale = ctx->priv;
66 sws_freeContext(scale->sws);
67 scale->sws = NULL;
68}
69
70static int query_formats(AVFilterContext *ctx)
71{
72 AVFilterFormats *formats;
73
74 if (ctx->inputs[0]) {
75 formats = avfilter_all_colorspaces();
76 avfilter_formats_ref(formats, &ctx->inputs[0]->out_formats);
77 }
78 if (ctx->outputs[0]) {
79 formats = avfilter_all_colorspaces();
80 avfilter_formats_ref(formats, &ctx->outputs[0]->in_formats);
81 }
82
83 return 0;
84}
85
86static int config_props(AVFilterLink *outlink)
87{
88 AVFilterContext *ctx = outlink->src;
89 AVFilterLink *inlink = outlink->src->inputs[0];
90 ScaleContext *scale = ctx->priv;
91 int64_t w, h;
92
93 if (!(w = scale->w))
94 w = inlink->w;
95 if (!(h = scale->h))
96 h = inlink->h;
97 if (w == -1)
98 w = av_rescale(h, inlink->w, inlink->h);
99 if (h == -1)
100 h = av_rescale(w, inlink->h, inlink->w);
101
102 if (w > INT_MAX || h > INT_MAX ||
103 (h * inlink->w) > INT_MAX ||
104 (w * inlink->h) > INT_MAX)
105 av_log(ctx, AV_LOG_ERROR, "Rescaled value for width or height is too big.\n");
106
107 outlink->w = w;
108 outlink->h = h;
109
110 /* TODO: make algorithm configurable */
111 scale->sws = sws_getContext(inlink ->w, inlink ->h, inlink ->format,
112 outlink->w, outlink->h, outlink->format,
113 SWS_BILINEAR, NULL, NULL, NULL);
114
115 av_log(ctx, AV_LOG_INFO, "w:%d h:%d fmt:%s\n",
116 outlink->w, outlink->h, avcodec_get_pix_fmt_name(outlink->format));
117
118 avcodec_get_chroma_sub_sample(outlink->format, &scale->hsub, &scale->vsub);
119
120 scale->input_is_pal = inlink->format == PIX_FMT_PAL8 ||
121 inlink->format == PIX_FMT_BGR4_BYTE ||
122 inlink->format == PIX_FMT_RGB4_BYTE ||
123 inlink->format == PIX_FMT_BGR8 ||
124 inlink->format == PIX_FMT_RGB8;
125
126 return !scale->sws;
127}
128
129static void start_frame(AVFilterLink *link, AVFilterPicRef *picref)
130{
131 ScaleContext *scale = link->dst->priv;
132 AVFilterLink *outlink = link->dst->outputs[0];
133 AVFilterPicRef *outpicref;
134
135 outpicref = avfilter_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
136 outpicref->pts = picref->pts;
137 outlink->outpic = outpicref;
138
139 av_reduce(&outpicref->pixel_aspect.num, &outpicref->pixel_aspect.den,
140 (int64_t)picref->pixel_aspect.num * outlink->h * link->w,
141 (int64_t)picref->pixel_aspect.den * outlink->w * link->h,
142 INT_MAX);
143
144 scale->slice_dir = 0;
145 avfilter_start_frame(outlink, avfilter_ref_pic(outpicref, ~0));
146}
147
148static void draw_slice(AVFilterLink *link, int y, int h)
149{
150 ScaleContext *scale = link->dst->priv;
151 int out_h;
152 AVFilterPicRef *cur_pic = link->cur_pic;
153 uint8_t *data[4];
154
155 if (!scale->slice_dir) {
156 if (y != 0 && y + h != link->h) {
157 av_log(scale, AV_LOG_ERROR, "Slices start in the middle!\n");
158 return;
159 }
160 scale->slice_dir = y ? -1 : 1;
161 scale->slice_y = y ? link->dst->outputs[0]->h : y;
162 }
163
164 data[0] = cur_pic->data[0] + y * cur_pic->linesize[0];
165 data[1] = scale->input_is_pal ?
166 cur_pic->data[1] :
167 cur_pic->data[1] + (y>>scale->vsub) * cur_pic->linesize[1];
168 data[2] = cur_pic->data[2] + (y>>scale->vsub) * cur_pic->linesize[2];
169 data[3] = cur_pic->data[3] + y * cur_pic->linesize[3];
170
171 out_h = sws_scale(scale->sws, data, cur_pic->linesize, y, h,
172 link->dst->outputs[0]->outpic->data,
173 link->dst->outputs[0]->outpic->linesize);
174
175 if (scale->slice_dir == -1)
176 scale->slice_y -= out_h;
177 avfilter_draw_slice(link->dst->outputs[0], scale->slice_y, out_h);
178 if (scale->slice_dir == 1)
179 scale->slice_y += out_h;
180}
181
182AVFilter avfilter_vf_scale = {
183 .name = "scale",
184 .description = "Scale the input video to width:height size and/or convert the image format.",
185
186 .init = init,
187 .uninit = uninit,
188
189 .query_formats = query_formats,
190
191 .priv_size = sizeof(ScaleContext),
192
193 .inputs = (AVFilterPad[]) {{ .name = "default",
194 .type = CODEC_TYPE_VIDEO,
195 .start_frame = start_frame,
196 .draw_slice = draw_slice,
197 .min_perms = AV_PERM_READ, },
198 { .name = NULL}},
199 .outputs = (AVFilterPad[]) {{ .name = "default",
200 .type = CODEC_TYPE_VIDEO,
201 .config_props = config_props, },
202 { .name = NULL}},
203};