1/* 2 * Copyright (c) 2007 Bobby Bingham 3 * 4 * This file is part of Libav. 5 * 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. 10 * 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. 15 * 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 19 */ 20 21/** 22 * @file 23 * scale video filter 24 */ 25 26#include "avfilter.h" 27#include "libavutil/avstring.h" 28#include "libavutil/eval.h" 29#include "libavutil/mathematics.h" 30#include "libavutil/pixdesc.h" 31#include "libswscale/swscale.h" 32 33static const char *var_names[] = { 34 "PI", 35 "PHI", 36 "E", 37 "in_w", "iw", 38 "in_h", "ih", 39 "out_w", "ow", 40 "out_h", "oh", 41 "a", "dar", 42 "sar", 43 "hsub", 44 "vsub", 45 NULL 46}; 47 48enum var_name { 49 VAR_PI, 50 VAR_PHI, 51 VAR_E, 52 VAR_IN_W, VAR_IW, 53 VAR_IN_H, VAR_IH, 54 VAR_OUT_W, VAR_OW, 55 VAR_OUT_H, VAR_OH, 56 VAR_A, VAR_DAR, 57 VAR_SAR, 58 VAR_HSUB, 59 VAR_VSUB, 60 VARS_NB 61}; 62 63typedef struct { 64 struct SwsContext *sws; ///< software scaler context 65 66 /** 67 * New dimensions. Special values are: 68 * 0 = original width/height 69 * -1 = keep original aspect 70 */ 71 int w, h; 72 unsigned int flags; ///sws flags 73 74 int hsub, vsub; ///< chroma subsampling 75 int slice_y; ///< top of current output slice 76 int input_is_pal; ///< set to 1 if the input format is paletted 77 78 char w_expr[256]; ///< width expression string 79 char h_expr[256]; ///< height expression string 80} ScaleContext; 81 82static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque) 83{ 84 ScaleContext *scale = ctx->priv; 85 const char *p; 86 87 av_strlcpy(scale->w_expr, "iw", sizeof(scale->w_expr)); 88 av_strlcpy(scale->h_expr, "ih", sizeof(scale->h_expr)); 89 90 scale->flags = SWS_BILINEAR; 91 if (args) { 92 sscanf(args, "%255[^:]:%255[^:]", scale->w_expr, scale->h_expr); 93 p = strstr(args,"flags="); 94 if (p) scale->flags = strtoul(p+6, NULL, 0); 95 } 96 97 return 0; 98} 99 100static av_cold void uninit(AVFilterContext *ctx) 101{ 102 ScaleContext *scale = ctx->priv; 103 sws_freeContext(scale->sws); 104 scale->sws = NULL; 105} 106 107static int query_formats(AVFilterContext *ctx) 108{ 109 AVFilterFormats *formats; 110 enum PixelFormat pix_fmt; 111 int ret; 112 113 if (ctx->inputs[0]) { 114 formats = NULL; 115 for (pix_fmt = 0; pix_fmt < PIX_FMT_NB; pix_fmt++) 116 if ( sws_isSupportedInput(pix_fmt) 117 && (ret = avfilter_add_format(&formats, pix_fmt)) < 0) { 118 avfilter_formats_unref(&formats); 119 return ret; 120 } 121 avfilter_formats_ref(formats, &ctx->inputs[0]->out_formats); 122 } 123 if (ctx->outputs[0]) { 124 formats = NULL; 125 for (pix_fmt = 0; pix_fmt < PIX_FMT_NB; pix_fmt++) 126 if ( sws_isSupportedOutput(pix_fmt) 127 && (ret = avfilter_add_format(&formats, pix_fmt)) < 0) { 128 avfilter_formats_unref(&formats); 129 return ret; 130 } 131 avfilter_formats_ref(formats, &ctx->outputs[0]->in_formats); 132 } 133 134 return 0; 135} 136 137static int config_props(AVFilterLink *outlink) 138{ 139 AVFilterContext *ctx = outlink->src; 140 AVFilterLink *inlink = outlink->src->inputs[0]; 141 ScaleContext *scale = ctx->priv; 142 int64_t w, h; 143 double var_values[VARS_NB], res; 144 char *expr; 145 int ret; 146 147 var_values[VAR_PI] = M_PI; 148 var_values[VAR_PHI] = M_PHI; 149 var_values[VAR_E] = M_E; 150 var_values[VAR_IN_W] = var_values[VAR_IW] = inlink->w; 151 var_values[VAR_IN_H] = var_values[VAR_IH] = inlink->h; 152 var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN; 153 var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN; 154 var_values[VAR_DAR] = var_values[VAR_A] = (double) inlink->w / inlink->h; 155 var_values[VAR_SAR] = inlink->sample_aspect_ratio.num ? 156 (double) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1; 157 var_values[VAR_HSUB] = 1<<av_pix_fmt_descriptors[inlink->format].log2_chroma_w; 158 var_values[VAR_VSUB] = 1<<av_pix_fmt_descriptors[inlink->format].log2_chroma_h; 159 160 /* evaluate width and height */ 161 av_expr_parse_and_eval(&res, (expr = scale->w_expr), 162 var_names, var_values, 163 NULL, NULL, NULL, NULL, NULL, 0, ctx); 164 scale->w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res; 165 if ((ret = av_expr_parse_and_eval(&res, (expr = scale->h_expr), 166 var_names, var_values, 167 NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) 168 goto fail; 169 scale->h = var_values[VAR_OUT_H] = var_values[VAR_OH] = res; 170 /* evaluate again the width, as it may depend on the output height */ 171 if ((ret = av_expr_parse_and_eval(&res, (expr = scale->w_expr), 172 var_names, var_values, 173 NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) 174 goto fail; 175 scale->w = res; 176 177 w = scale->w; 178 h = scale->h; 179 180 /* sanity check params */ 181 if (w < -1 || h < -1) { 182 av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n"); 183 return AVERROR(EINVAL); 184 } 185 if (w == -1 && h == -1) 186 scale->w = scale->h = 0; 187 188 if (!(w = scale->w)) 189 w = inlink->w; 190 if (!(h = scale->h)) 191 h = inlink->h; 192 if (w == -1) 193 w = av_rescale(h, inlink->w, inlink->h); 194 if (h == -1) 195 h = av_rescale(w, inlink->h, inlink->w); 196 197 if (w > INT_MAX || h > INT_MAX || 198 (h * inlink->w) > INT_MAX || 199 (w * inlink->h) > INT_MAX) 200 av_log(ctx, AV_LOG_ERROR, "Rescaled value for width or height is too big.\n"); 201 202 outlink->w = w; 203 outlink->h = h; 204 205 /* TODO: make algorithm configurable */ 206 av_log(ctx, AV_LOG_INFO, "w:%d h:%d fmt:%s -> w:%d h:%d fmt:%s flags:0x%0x\n", 207 inlink ->w, inlink ->h, av_pix_fmt_descriptors[ inlink->format].name, 208 outlink->w, outlink->h, av_pix_fmt_descriptors[outlink->format].name, 209 scale->flags); 210 211 scale->input_is_pal = av_pix_fmt_descriptors[inlink->format].flags & PIX_FMT_PAL; 212 213 if (scale->sws) 214 sws_freeContext(scale->sws); 215 scale->sws = sws_getContext(inlink ->w, inlink ->h, inlink ->format, 216 outlink->w, outlink->h, outlink->format, 217 scale->flags, NULL, NULL, NULL); 218 if (!scale->sws) 219 return AVERROR(EINVAL); 220 221 222 if (inlink->sample_aspect_ratio.num) 223 outlink->sample_aspect_ratio = av_mul_q((AVRational){outlink->h*inlink->w, 224 outlink->w*inlink->h}, 225 inlink->sample_aspect_ratio); 226 else 227 outlink->sample_aspect_ratio = inlink->sample_aspect_ratio; 228 229 return 0; 230 231fail: 232 av_log(NULL, AV_LOG_ERROR, 233 "Error when evaluating the expression '%s'\n", expr); 234 return ret; 235} 236 237static void start_frame(AVFilterLink *link, AVFilterBufferRef *picref) 238{ 239 ScaleContext *scale = link->dst->priv; 240 AVFilterLink *outlink = link->dst->outputs[0]; 241 AVFilterBufferRef *outpicref; 242 243 scale->hsub = av_pix_fmt_descriptors[link->format].log2_chroma_w; 244 scale->vsub = av_pix_fmt_descriptors[link->format].log2_chroma_h; 245 246 outpicref = avfilter_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h); 247 avfilter_copy_buffer_ref_props(outpicref, picref); 248 outpicref->video->w = outlink->w; 249 outpicref->video->h = outlink->h; 250 251 outlink->out_buf = outpicref; 252 253 av_reduce(&outpicref->video->pixel_aspect.num, &outpicref->video->pixel_aspect.den, 254 (int64_t)picref->video->pixel_aspect.num * outlink->h * link->w, 255 (int64_t)picref->video->pixel_aspect.den * outlink->w * link->h, 256 INT_MAX); 257 258 scale->slice_y = 0; 259 avfilter_start_frame(outlink, avfilter_ref_buffer(outpicref, ~0)); 260} 261 262static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir) 263{ 264 ScaleContext *scale = link->dst->priv; 265 int out_h; 266 AVFilterBufferRef *cur_pic = link->cur_buf; 267 const uint8_t *data[4]; 268 269 if (scale->slice_y == 0 && slice_dir == -1) 270 scale->slice_y = link->dst->outputs[0]->h; 271 272 data[0] = cur_pic->data[0] + y * cur_pic->linesize[0]; 273 data[1] = scale->input_is_pal ? 274 cur_pic->data[1] : 275 cur_pic->data[1] + (y>>scale->vsub) * cur_pic->linesize[1]; 276 data[2] = cur_pic->data[2] + (y>>scale->vsub) * cur_pic->linesize[2]; 277 data[3] = cur_pic->data[3] + y * cur_pic->linesize[3]; 278 279 out_h = sws_scale(scale->sws, data, cur_pic->linesize, y, h, 280 link->dst->outputs[0]->out_buf->data, 281 link->dst->outputs[0]->out_buf->linesize); 282 283 if (slice_dir == -1) 284 scale->slice_y -= out_h; 285 avfilter_draw_slice(link->dst->outputs[0], scale->slice_y, out_h, slice_dir); 286 if (slice_dir == 1) 287 scale->slice_y += out_h; 288} 289 290AVFilter avfilter_vf_scale = { 291 .name = "scale", 292 .description = NULL_IF_CONFIG_SMALL("Scale the input video to width:height size and/or convert the image format."), 293 294 .init = init, 295 .uninit = uninit, 296 297 .query_formats = query_formats, 298 299 .priv_size = sizeof(ScaleContext), 300 301 .inputs = (AVFilterPad[]) {{ .name = "default", 302 .type = AVMEDIA_TYPE_VIDEO, 303 .start_frame = start_frame, 304 .draw_slice = draw_slice, 305 .min_perms = AV_PERM_READ, }, 306 { .name = NULL}}, 307 .outputs = (AVFilterPad[]) {{ .name = "default", 308 .type = AVMEDIA_TYPE_VIDEO, 309 .config_props = config_props, }, 310 { .name = NULL}}, 311}; 312