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
33 #include "libavutil/avstring.h"
34 #include "libavutil/eval.h"
35 #include "libavutil/internal.h"
36 #include "libavutil/mathematics.h"
37 #include "libavutil/opt.h"
38 #include "libavutil/pixdesc.h"
39 #include "libswscale/swscale.h"
41 static const char *const var_names[] = {
72 struct SwsContext *sws; ///< software scaler context
75 * New dimensions. Special values are:
76 * 0 = original width/height
77 * -1 = keep original aspect
80 unsigned int flags; ///sws flags
82 int hsub, vsub; ///< chroma subsampling
83 int slice_y; ///< top of current output slice
84 int input_is_pal; ///< set to 1 if the input format is paletted
86 char w_expr[256]; ///< width expression string
87 char h_expr[256]; ///< height expression string
90 static av_cold int init(AVFilterContext *ctx, const char *args)
92 ScaleContext *scale = ctx->priv;
95 av_strlcpy(scale->w_expr, "iw", sizeof(scale->w_expr));
96 av_strlcpy(scale->h_expr, "ih", sizeof(scale->h_expr));
98 scale->flags = SWS_BILINEAR;
100 sscanf(args, "%255[^:]:%255[^:]", scale->w_expr, scale->h_expr);
101 p = strstr(args,"flags=");
103 const AVClass *class = sws_get_class();
104 const AVOption *o = av_opt_find(&class, "sws_flags", NULL, 0,
105 AV_OPT_SEARCH_FAKE_OBJ);
106 int ret = av_opt_eval_flags(&class, o, p + 6, &scale->flags);
116 static av_cold void uninit(AVFilterContext *ctx)
118 ScaleContext *scale = ctx->priv;
119 sws_freeContext(scale->sws);
123 static int query_formats(AVFilterContext *ctx)
125 AVFilterFormats *formats;
126 enum AVPixelFormat pix_fmt;
129 if (ctx->inputs[0]) {
131 for (pix_fmt = 0; pix_fmt < AV_PIX_FMT_NB; pix_fmt++)
132 if ( sws_isSupportedInput(pix_fmt)
133 && (ret = ff_add_format(&formats, pix_fmt)) < 0) {
134 ff_formats_unref(&formats);
137 ff_formats_ref(formats, &ctx->inputs[0]->out_formats);
139 if (ctx->outputs[0]) {
141 for (pix_fmt = 0; pix_fmt < AV_PIX_FMT_NB; pix_fmt++)
142 if ( sws_isSupportedOutput(pix_fmt)
143 && (ret = ff_add_format(&formats, pix_fmt)) < 0) {
144 ff_formats_unref(&formats);
147 ff_formats_ref(formats, &ctx->outputs[0]->in_formats);
153 static int config_props(AVFilterLink *outlink)
155 AVFilterContext *ctx = outlink->src;
156 AVFilterLink *inlink = outlink->src->inputs[0];
157 ScaleContext *scale = ctx->priv;
158 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
160 double var_values[VARS_NB], res;
164 var_values[VAR_PI] = M_PI;
165 var_values[VAR_PHI] = M_PHI;
166 var_values[VAR_E] = M_E;
167 var_values[VAR_IN_W] = var_values[VAR_IW] = inlink->w;
168 var_values[VAR_IN_H] = var_values[VAR_IH] = inlink->h;
169 var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
170 var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;
171 var_values[VAR_DAR] = var_values[VAR_A] = (double) inlink->w / inlink->h;
172 var_values[VAR_SAR] = inlink->sample_aspect_ratio.num ?
173 (double) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1;
174 var_values[VAR_HSUB] = 1 << desc->log2_chroma_w;
175 var_values[VAR_VSUB] = 1 << desc->log2_chroma_h;
177 /* evaluate width and height */
178 av_expr_parse_and_eval(&res, (expr = scale->w_expr),
179 var_names, var_values,
180 NULL, NULL, NULL, NULL, NULL, 0, ctx);
181 scale->w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res;
182 if ((ret = av_expr_parse_and_eval(&res, (expr = scale->h_expr),
183 var_names, var_values,
184 NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
186 scale->h = var_values[VAR_OUT_H] = var_values[VAR_OH] = res;
187 /* evaluate again the width, as it may depend on the output height */
188 if ((ret = av_expr_parse_and_eval(&res, (expr = scale->w_expr),
189 var_names, var_values,
190 NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
197 /* sanity check params */
198 if (w < -1 || h < -1) {
199 av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n");
200 return AVERROR(EINVAL);
202 if (w == -1 && h == -1)
203 scale->w = scale->h = 0;
210 w = av_rescale(h, inlink->w, inlink->h);
212 h = av_rescale(w, inlink->h, inlink->w);
214 if (w > INT_MAX || h > INT_MAX ||
215 (h * inlink->w) > INT_MAX ||
216 (w * inlink->h) > INT_MAX)
217 av_log(ctx, AV_LOG_ERROR, "Rescaled value for width or height is too big.\n");
222 /* TODO: make algorithm configurable */
223 av_log(ctx, AV_LOG_VERBOSE, "w:%d h:%d fmt:%s -> w:%d h:%d fmt:%s flags:0x%0x\n",
224 inlink ->w, inlink ->h, av_get_pix_fmt_name(inlink->format),
225 outlink->w, outlink->h, av_get_pix_fmt_name(outlink->format),
228 scale->input_is_pal = desc->flags & PIX_FMT_PAL ||
229 desc->flags & PIX_FMT_PSEUDOPAL;
232 sws_freeContext(scale->sws);
233 if (inlink->w == outlink->w && inlink->h == outlink->h &&
234 inlink->format == outlink->format)
237 scale->sws = sws_getContext(inlink ->w, inlink ->h, inlink ->format,
238 outlink->w, outlink->h, outlink->format,
239 scale->flags, NULL, NULL, NULL);
241 return AVERROR(EINVAL);
245 if (inlink->sample_aspect_ratio.num)
246 outlink->sample_aspect_ratio = av_mul_q((AVRational){outlink->h*inlink->w,
247 outlink->w*inlink->h},
248 inlink->sample_aspect_ratio);
250 outlink->sample_aspect_ratio = inlink->sample_aspect_ratio;
255 av_log(NULL, AV_LOG_ERROR,
256 "Error when evaluating the expression '%s'\n", expr);
260 static int filter_frame(AVFilterLink *link, AVFilterBufferRef *in)
262 ScaleContext *scale = link->dst->priv;
263 AVFilterLink *outlink = link->dst->outputs[0];
264 AVFilterBufferRef *out;
265 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(link->format);
268 return ff_filter_frame(outlink, in);
270 scale->hsub = desc->log2_chroma_w;
271 scale->vsub = desc->log2_chroma_h;
273 out = ff_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
275 avfilter_unref_bufferp(&in);
276 return AVERROR(ENOMEM);
279 avfilter_copy_buffer_ref_props(out, in);
280 out->video->w = outlink->w;
281 out->video->h = outlink->h;
283 av_reduce(&out->video->pixel_aspect.num, &out->video->pixel_aspect.den,
284 (int64_t)in->video->pixel_aspect.num * outlink->h * link->w,
285 (int64_t)in->video->pixel_aspect.den * outlink->w * link->h,
288 sws_scale(scale->sws, in->data, in->linesize, 0, in->video->h,
289 out->data, out->linesize);
291 avfilter_unref_bufferp(&in);
292 return ff_filter_frame(outlink, out);
295 static const AVFilterPad avfilter_vf_scale_inputs[] = {
298 .type = AVMEDIA_TYPE_VIDEO,
299 .filter_frame = filter_frame,
300 .min_perms = AV_PERM_READ,
305 static const AVFilterPad avfilter_vf_scale_outputs[] = {
308 .type = AVMEDIA_TYPE_VIDEO,
309 .config_props = config_props,
314 AVFilter avfilter_vf_scale = {
316 .description = NULL_IF_CONFIG_SMALL("Scale the input video to width:height size and/or convert the image format."),
321 .query_formats = query_formats,
323 .priv_size = sizeof(ScaleContext),
325 .inputs = avfilter_vf_scale_inputs,
326 .outputs = avfilter_vf_scale_outputs,