libavfilter/vf_scale.c

   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 <stdio.h>
  27 #include <string.h>
  28
  29 #include "avfilter.h"
  30 #include "formats.h"
  31 #include "internal.h"
  32 #include "video.h"
  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"
  40
  41 static const char *const var_names[] = {
  42     "PI",
  43     "PHI",
  44     "E",
  45     "in_w",   "iw",
  46     "in_h",   "ih",
  47     "out_w",  "ow",
  48     "out_h",  "oh",
  49     "a", "dar",
  50     "sar",
  51     "hsub",
  52     "vsub",
  53     NULL
  54 };
  55
  56 enum var_name {
  57     VAR_PI,
  58     VAR_PHI,
  59     VAR_E,
  60     VAR_IN_W,   VAR_IW,
  61     VAR_IN_H,   VAR_IH,
  62     VAR_OUT_W,  VAR_OW,
  63     VAR_OUT_H,  VAR_OH,
  64     VAR_A, VAR_DAR,
  65     VAR_SAR,
  66     VAR_HSUB,
  67     VAR_VSUB,
  68     VARS_NB
  69 };
  70
  71 typedef struct {
  72     struct SwsContext *sws;     ///< software scaler context
  73
  74     /**
  75      * New dimensions. Special values are:
  76      *   0 = original width/height
  77      *  -1 = keep original aspect
  78      */
  79     int w, h;
  80     unsigned int flags;         ///sws flags
  81
  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
  85
  86     char w_expr[256];           ///< width  expression string
  87     char h_expr[256];           ///< height expression string
  88 } ScaleContext;
  89
  90 static av_cold int init(AVFilterContext *ctx, const char *args)
  91 {
  92     ScaleContext *scale = ctx->priv;
  93     const char *p;
  94
  95     av_strlcpy(scale->w_expr, "iw", sizeof(scale->w_expr));
  96     av_strlcpy(scale->h_expr, "ih", sizeof(scale->h_expr));
  97
  98     scale->flags = SWS_BILINEAR;
  99     if (args) {
 100         sscanf(args, "%255[^:]:%255[^:]", scale->w_expr, scale->h_expr);
 101         p = strstr(args,"flags=");
 102         if (p) {
 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);
 107
 108             if (ret < 0)
 109                 return ret;
 110         }
 111     }
 112
 113     return 0;
 114 }
 115
 116 static av_cold void uninit(AVFilterContext *ctx)
 117 {
 118     ScaleContext *scale = ctx->priv;
 119     sws_freeContext(scale->sws);
 120     scale->sws = NULL;
 121 }
 122
 123 static int query_formats(AVFilterContext *ctx)
 124 {
 125     AVFilterFormats *formats;
 126     enum AVPixelFormat pix_fmt;
 127     int ret;
 128
 129     if (ctx->inputs[0]) {
 130         formats = NULL;
 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);
 135                 return ret;
 136             }
 137         ff_formats_ref(formats, &ctx->inputs[0]->out_formats);
 138     }
 139     if (ctx->outputs[0]) {
 140         formats = NULL;
 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);
 145                 return ret;
 146             }
 147         ff_formats_ref(formats, &ctx->outputs[0]->in_formats);
 148     }
 149
 150     return 0;
 151 }
 152
 153 static int config_props(AVFilterLink *outlink)
 154 {
 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);
 159     int64_t w, h;
 160     double var_values[VARS_NB], res;
 161     char *expr;
 162     int ret;
 163
 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;
 176
 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)
 185         goto fail;
 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)
 191         goto fail;
 192     scale->w = res;
 193
 194     w = scale->w;
 195     h = scale->h;
 196
 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);
 201     }
 202     if (w == -1 && h == -1)
 203         scale->w = scale->h = 0;
 204
 205     if (!(w = scale->w))
 206         w = inlink->w;
 207     if (!(h = scale->h))
 208         h = inlink->h;
 209     if (w == -1)
 210         w = av_rescale(h, inlink->w, inlink->h);
 211     if (h == -1)
 212         h = av_rescale(w, inlink->h, inlink->w);
 213
 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");
 218
 219     outlink->w = w;
 220     outlink->h = h;
 221
 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),
 226            scale->flags);
 227
 228     scale->input_is_pal = desc->flags & PIX_FMT_PAL ||
 229                           desc->flags & PIX_FMT_PSEUDOPAL;
 230
 231     if (scale->sws)
 232         sws_freeContext(scale->sws);
 233     if (inlink->w == outlink->w && inlink->h == outlink->h &&
 234         inlink->format == outlink->format)
 235         scale->sws = NULL;
 236     else {
 237         scale->sws = sws_getContext(inlink ->w, inlink ->h, inlink ->format,
 238                                     outlink->w, outlink->h, outlink->format,
 239                                     scale->flags, NULL, NULL, NULL);
 240         if (!scale->sws)
 241             return AVERROR(EINVAL);
 242     }
 243
 244
 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);
 249     else
 250         outlink->sample_aspect_ratio = inlink->sample_aspect_ratio;
 251
 252     return 0;
 253
 254 fail:
 255     av_log(NULL, AV_LOG_ERROR,
 256            "Error when evaluating the expression '%s'\n", expr);
 257     return ret;
 258 }
 259
 260 static int filter_frame(AVFilterLink *link, AVFilterBufferRef *in)
 261 {
 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);
 266
 267     if (!scale->sws)
 268         return ff_filter_frame(outlink, in);
 269
 270     scale->hsub = desc->log2_chroma_w;
 271     scale->vsub = desc->log2_chroma_h;
 272
 273     out = ff_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
 274     if (!out) {
 275         avfilter_unref_bufferp(&in);
 276         return AVERROR(ENOMEM);
 277     }
 278
 279     avfilter_copy_buffer_ref_props(out, in);
 280     out->video->w = outlink->w;
 281     out->video->h = outlink->h;
 282
 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,
 286               INT_MAX);
 287
 288     sws_scale(scale->sws, in->data, in->linesize, 0, in->video->h,
 289               out->data, out->linesize);
 290
 291     avfilter_unref_bufferp(&in);
 292     return ff_filter_frame(outlink, out);
 293 }
 294
 295 static const AVFilterPad avfilter_vf_scale_inputs[] = {
 296     {
 297         .name        = "default",
 298         .type        = AVMEDIA_TYPE_VIDEO,
 299         .filter_frame = filter_frame,
 300         .min_perms   = AV_PERM_READ,
 301     },
 302     { NULL }
 303 };
 304
 305 static const AVFilterPad avfilter_vf_scale_outputs[] = {
 306     {
 307         .name         = "default",
 308         .type         = AVMEDIA_TYPE_VIDEO,
 309         .config_props = config_props,
 310     },
 311     { NULL }
 312 };
 313
 314 AVFilter avfilter_vf_scale = {
 315     .name      = "scale",
 316     .description = NULL_IF_CONFIG_SMALL("Scale the input video to width:height size and/or convert the image format."),
 317
 318     .init      = init,
 319     .uninit    = uninit,
 320
 321     .query_formats = query_formats,
 322
 323     .priv_size = sizeof(ScaleContext),
 324
 325     .inputs    = avfilter_vf_scale_inputs,
 326     .outputs   = avfilter_vf_scale_outputs,
 327 };