2 * Copyright (c) 2007 Bobby Bingham
4 * This file is part of Libav.
6 * Libav 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.
11 * Libav 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.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with Libav; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
27 #include "libavutil/avstring.h"
28 #include "libavutil/eval.h"
29 #include "libavutil/pixdesc.h"
30 #include "libswscale/swscale.h"
32 static const char *var_names[] = {
61 struct SwsContext *sws; ///< software scaler context
64 * New dimensions. Special values are:
65 * 0 = original width/height
66 * -1 = keep original aspect
69 unsigned int flags; ///sws flags
71 int hsub, vsub; ///< chroma subsampling
72 int slice_y; ///< top of current output slice
73 int input_is_pal; ///< set to 1 if the input format is paletted
75 char w_expr[256]; ///< width expression string
76 char h_expr[256]; ///< height expression string
79 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
81 ScaleContext *scale = ctx->priv;
84 av_strlcpy(scale->w_expr, "iw", sizeof(scale->w_expr));
85 av_strlcpy(scale->h_expr, "ih", sizeof(scale->h_expr));
87 scale->flags = SWS_BILINEAR;
89 sscanf(args, "%255[^:]:%255[^:]", scale->w_expr, scale->h_expr);
90 p = strstr(args,"flags=");
91 if (p) scale->flags = strtoul(p+6, NULL, 0);
97 static av_cold void uninit(AVFilterContext *ctx)
99 ScaleContext *scale = ctx->priv;
100 sws_freeContext(scale->sws);
104 static int query_formats(AVFilterContext *ctx)
106 AVFilterFormats *formats;
107 enum PixelFormat pix_fmt;
110 if (ctx->inputs[0]) {
112 for (pix_fmt = 0; pix_fmt < PIX_FMT_NB; pix_fmt++)
113 if ( sws_isSupportedInput(pix_fmt)
114 && (ret = avfilter_add_format(&formats, pix_fmt)) < 0) {
115 avfilter_formats_unref(&formats);
118 avfilter_formats_ref(formats, &ctx->inputs[0]->out_formats);
120 if (ctx->outputs[0]) {
122 for (pix_fmt = 0; pix_fmt < PIX_FMT_NB; pix_fmt++)
123 if ( sws_isSupportedOutput(pix_fmt)
124 && (ret = avfilter_add_format(&formats, pix_fmt)) < 0) {
125 avfilter_formats_unref(&formats);
128 avfilter_formats_ref(formats, &ctx->outputs[0]->in_formats);
134 static int config_props(AVFilterLink *outlink)
136 AVFilterContext *ctx = outlink->src;
137 AVFilterLink *inlink = outlink->src->inputs[0];
138 ScaleContext *scale = ctx->priv;
140 double var_values[VARS_NB], res;
144 var_values[VAR_PI] = M_PI;
145 var_values[VAR_PHI] = M_PHI;
146 var_values[VAR_E] = M_E;
147 var_values[VAR_IN_W] = var_values[VAR_IW] = inlink->w;
148 var_values[VAR_IN_H] = var_values[VAR_IH] = inlink->h;
149 var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
150 var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;
151 var_values[VAR_A] = (float) inlink->w / inlink->h;
152 var_values[VAR_HSUB] = 1<<av_pix_fmt_descriptors[inlink->format].log2_chroma_w;
153 var_values[VAR_VSUB] = 1<<av_pix_fmt_descriptors[inlink->format].log2_chroma_h;
155 /* evaluate width and height */
156 av_expr_parse_and_eval(&res, (expr = scale->w_expr),
157 var_names, var_values,
158 NULL, NULL, NULL, NULL, NULL, 0, ctx);
159 scale->w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res;
160 if ((ret = av_expr_parse_and_eval(&res, (expr = scale->h_expr),
161 var_names, var_values,
162 NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
164 scale->h = var_values[VAR_OUT_H] = var_values[VAR_OH] = res;
165 /* evaluate again the width, as it may depend on the output height */
166 if ((ret = av_expr_parse_and_eval(&res, (expr = scale->w_expr),
167 var_names, var_values,
168 NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
175 /* sanity check params */
176 if (w < -1 || h < -1) {
177 av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n");
178 return AVERROR(EINVAL);
180 if (w == -1 && h == -1)
181 scale->w = scale->h = 0;
188 w = av_rescale(h, inlink->w, inlink->h);
190 h = av_rescale(w, inlink->h, inlink->w);
192 if (w > INT_MAX || h > INT_MAX ||
193 (h * inlink->w) > INT_MAX ||
194 (w * inlink->h) > INT_MAX)
195 av_log(ctx, AV_LOG_ERROR, "Rescaled value for width or height is too big.\n");
200 /* TODO: make algorithm configurable */
201 av_log(ctx, AV_LOG_INFO, "w:%d h:%d fmt:%s -> w:%d h:%d fmt:%s flags:0x%0x\n",
202 inlink ->w, inlink ->h, av_pix_fmt_descriptors[ inlink->format].name,
203 outlink->w, outlink->h, av_pix_fmt_descriptors[outlink->format].name,
206 scale->input_is_pal = av_pix_fmt_descriptors[inlink->format].flags & PIX_FMT_PAL;
208 scale->sws = sws_getContext(inlink ->w, inlink ->h, inlink ->format,
209 outlink->w, outlink->h, outlink->format,
210 scale->flags, NULL, NULL, NULL);
212 return AVERROR(EINVAL);
217 av_log(NULL, AV_LOG_ERROR,
218 "Error when evaluating the expression '%s'\n", expr);
222 static void start_frame(AVFilterLink *link, AVFilterBufferRef *picref)
224 ScaleContext *scale = link->dst->priv;
225 AVFilterLink *outlink = link->dst->outputs[0];
226 AVFilterBufferRef *outpicref;
228 scale->hsub = av_pix_fmt_descriptors[link->format].log2_chroma_w;
229 scale->vsub = av_pix_fmt_descriptors[link->format].log2_chroma_h;
231 outpicref = avfilter_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
232 avfilter_copy_buffer_ref_props(outpicref, picref);
233 outpicref->video->w = outlink->w;
234 outpicref->video->h = outlink->h;
236 outlink->out_buf = outpicref;
238 av_reduce(&outpicref->video->pixel_aspect.num, &outpicref->video->pixel_aspect.den,
239 (int64_t)picref->video->pixel_aspect.num * outlink->h * link->w,
240 (int64_t)picref->video->pixel_aspect.den * outlink->w * link->h,
244 avfilter_start_frame(outlink, avfilter_ref_buffer(outpicref, ~0));
247 static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
249 ScaleContext *scale = link->dst->priv;
251 AVFilterBufferRef *cur_pic = link->cur_buf;
252 const uint8_t *data[4];
254 if (scale->slice_y == 0 && slice_dir == -1)
255 scale->slice_y = link->dst->outputs[0]->h;
257 data[0] = cur_pic->data[0] + y * cur_pic->linesize[0];
258 data[1] = scale->input_is_pal ?
260 cur_pic->data[1] + (y>>scale->vsub) * cur_pic->linesize[1];
261 data[2] = cur_pic->data[2] + (y>>scale->vsub) * cur_pic->linesize[2];
262 data[3] = cur_pic->data[3] + y * cur_pic->linesize[3];
264 out_h = sws_scale(scale->sws, data, cur_pic->linesize, y, h,
265 link->dst->outputs[0]->out_buf->data,
266 link->dst->outputs[0]->out_buf->linesize);
269 scale->slice_y -= out_h;
270 avfilter_draw_slice(link->dst->outputs[0], scale->slice_y, out_h, slice_dir);
272 scale->slice_y += out_h;
275 AVFilter avfilter_vf_scale = {
277 .description = NULL_IF_CONFIG_SMALL("Scale the input video to width:height size and/or convert the image format."),
282 .query_formats = query_formats,
284 .priv_size = sizeof(ScaleContext),
286 .inputs = (AVFilterPad[]) {{ .name = "default",
287 .type = AVMEDIA_TYPE_VIDEO,
288 .start_frame = start_frame,
289 .draw_slice = draw_slice,
290 .min_perms = AV_PERM_READ, },
292 .outputs = (AVFilterPad[]) {{ .name = "default",
293 .type = AVMEDIA_TYPE_VIDEO,
294 .config_props = config_props, },