FFmpeg
 All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
vf_scale.c
Go to the documentation of this file.
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
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/parseutils.h"
39 #include "libavutil/pixdesc.h"
40 #include "libavutil/imgutils.h"
41 #include "libavutil/avassert.h"
42 #include "libswscale/swscale.h"
43 
44 static const char *const var_names[] = {
45  "in_w", "iw",
46  "in_h", "ih",
47  "out_w", "ow",
48  "out_h", "oh",
49  "a",
50  "sar",
51  "dar",
52  "hsub",
53  "vsub",
54  NULL
55 };
56 
57 enum var_name {
68 };
69 
70 typedef struct {
71  const AVClass *class;
72  struct SwsContext *sws; ///< software scaler context
73  struct SwsContext *isws[2]; ///< software scaler context for interlaced material
74 
75  /**
76  * New dimensions. Special values are:
77  * 0 = original width/height
78  * -1 = keep original aspect
79  */
80  int w, h;
81  char *flags_str; ///sws flags string
82  char *size_str;
83  unsigned int flags; ///sws flags
84 
85  int hsub, vsub; ///< chroma subsampling
86  int slice_y; ///< top of current output slice
87  int input_is_pal; ///< set to 1 if the input format is paletted
88  int output_is_pal; ///< set to 1 if the output format is paletted
90 
91  char *w_expr; ///< width expression string
92  char *h_expr; ///< height expression string
93 } ScaleContext;
94 
95 #define OFFSET(x) offsetof(ScaleContext, x)
96 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
97 
98 static const AVOption scale_options[] = {
99  { "w", "set width expression", OFFSET(w_expr), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
100  { "width", "set width expression", OFFSET(w_expr), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
101  { "h", "set height expression", OFFSET(h_expr), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
102  { "height", "set height expression", OFFSET(h_expr), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
103  { "flags", "set libswscale flags", OFFSET(flags_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, INT_MAX, FLAGS },
104  { "interl", "set interlacing", OFFSET(interlaced), AV_OPT_TYPE_INT, {.i64 = 0 }, -1, 1, FLAGS },
105  { "size", "set video size", OFFSET(size_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, FLAGS },
106  { "s", "set video size", OFFSET(size_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, FLAGS },
107  { NULL },
108 };
109 
111 
112 static av_cold int init(AVFilterContext *ctx, const char *args)
113 {
114  ScaleContext *scale = ctx->priv;
115  static const char *shorthand[] = { "w", "h", NULL };
116  int ret;
117  const char *args0 = args;
118 
119  scale->class = &scale_class;
120  av_opt_set_defaults(scale);
121 
122  if (args && (scale->size_str = av_get_token(&args, ":"))) {
123  if (av_parse_video_size(&scale->w, &scale->h, scale->size_str) < 0) {
124  av_freep(&scale->size_str);
125  args = args0;
126  } else if (*args)
127  args++;
128  }
129 
130  if ((ret = av_opt_set_from_string(scale, args, shorthand, "=", ":")) < 0)
131  return ret;
132 
133  if (scale->size_str && (scale->w_expr || scale->h_expr)) {
134  av_log(ctx, AV_LOG_ERROR,
135  "Size and width/height expressions cannot be set at the same time.\n");
136  return AVERROR(EINVAL);
137  }
138 
139  if (scale->size_str) {
140  char buf[32];
141  if ((ret = av_parse_video_size(&scale->w, &scale->h, scale->size_str)) < 0) {
142  av_log(ctx, AV_LOG_ERROR,
143  "Invalid size '%s'\n", scale->size_str);
144  return ret;
145  }
146  snprintf(buf, sizeof(buf)-1, "%d", scale->w);
147  av_opt_set(scale, "w", buf, 0);
148  snprintf(buf, sizeof(buf)-1, "%d", scale->h);
149  av_opt_set(scale, "h", buf, 0);
150  }
151  if (!scale->w_expr)
152  av_opt_set(scale, "w", "iw", 0);
153  if (!scale->h_expr)
154  av_opt_set(scale, "h", "ih", 0);
155 
156  av_log(ctx, AV_LOG_VERBOSE, "w:%s h:%s flags:'%s' interl:%d\n",
157  scale->w_expr, scale->h_expr, (char *)av_x_if_null(scale->flags_str, ""), scale->interlaced);
158 
159  scale->flags = SWS_BILINEAR;
160  if (scale->flags_str) {
161  const AVClass *class = sws_get_class();
162  const AVOption *o = av_opt_find(&class, "sws_flags", NULL, 0,
164  int ret = av_opt_eval_flags(&class, o, scale->flags_str, &scale->flags);
165  if (ret < 0)
166  return ret;
167  }
168 
169  return 0;
170 }
171 
172 static av_cold void uninit(AVFilterContext *ctx)
173 {
174  ScaleContext *scale = ctx->priv;
175  sws_freeContext(scale->sws);
176  sws_freeContext(scale->isws[0]);
177  sws_freeContext(scale->isws[1]);
178  scale->sws = NULL;
179  av_opt_free(scale);
180 }
181 
183 {
185  enum AVPixelFormat pix_fmt;
186  int ret;
187 
188  if (ctx->inputs[0]) {
189  formats = NULL;
190  for (pix_fmt = 0; pix_fmt < AV_PIX_FMT_NB; pix_fmt++)
191  if ( sws_isSupportedInput(pix_fmt)
192  && (ret = ff_add_format(&formats, pix_fmt)) < 0) {
193  ff_formats_unref(&formats);
194  return ret;
195  }
196  ff_formats_ref(formats, &ctx->inputs[0]->out_formats);
197  }
198  if (ctx->outputs[0]) {
199  formats = NULL;
200  for (pix_fmt = 0; pix_fmt < AV_PIX_FMT_NB; pix_fmt++)
201  if ( (sws_isSupportedOutput(pix_fmt) || pix_fmt == AV_PIX_FMT_PAL8)
202  && (ret = ff_add_format(&formats, pix_fmt)) < 0) {
203  ff_formats_unref(&formats);
204  return ret;
205  }
206  ff_formats_ref(formats, &ctx->outputs[0]->in_formats);
207  }
208 
209  return 0;
210 }
211 
212 static int config_props(AVFilterLink *outlink)
213 {
214  AVFilterContext *ctx = outlink->src;
215  AVFilterLink *inlink = outlink->src->inputs[0];
216  enum AVPixelFormat outfmt = outlink->format;
217  ScaleContext *scale = ctx->priv;
218  const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
219  int64_t w, h;
220  double var_values[VARS_NB], res;
221  char *expr;
222  int ret;
223 
224  var_values[VAR_IN_W] = var_values[VAR_IW] = inlink->w;
225  var_values[VAR_IN_H] = var_values[VAR_IH] = inlink->h;
226  var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
227  var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;
228  var_values[VAR_A] = (double) inlink->w / inlink->h;
229  var_values[VAR_SAR] = inlink->sample_aspect_ratio.num ?
230  (double) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1;
231  var_values[VAR_DAR] = var_values[VAR_A] * var_values[VAR_SAR];
232  var_values[VAR_HSUB] = 1 << desc->log2_chroma_w;
233  var_values[VAR_VSUB] = 1 << desc->log2_chroma_h;
234 
235  /* evaluate width and height */
236  av_expr_parse_and_eval(&res, (expr = scale->w_expr),
237  var_names, var_values,
238  NULL, NULL, NULL, NULL, NULL, 0, ctx);
239  scale->w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res;
240  if ((ret = av_expr_parse_and_eval(&res, (expr = scale->h_expr),
241  var_names, var_values,
242  NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
243  goto fail;
244  scale->h = var_values[VAR_OUT_H] = var_values[VAR_OH] = res;
245  /* evaluate again the width, as it may depend on the output height */
246  if ((ret = av_expr_parse_and_eval(&res, (expr = scale->w_expr),
247  var_names, var_values,
248  NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
249  goto fail;
250  scale->w = res;
251 
252  w = scale->w;
253  h = scale->h;
254 
255  /* sanity check params */
256  if (w < -1 || h < -1) {
257  av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n");
258  return AVERROR(EINVAL);
259  }
260  if (w == -1 && h == -1)
261  scale->w = scale->h = 0;
262 
263  if (!(w = scale->w))
264  w = inlink->w;
265  if (!(h = scale->h))
266  h = inlink->h;
267  if (w == -1)
268  w = av_rescale(h, inlink->w, inlink->h);
269  if (h == -1)
270  h = av_rescale(w, inlink->h, inlink->w);
271 
272  if (w > INT_MAX || h > INT_MAX ||
273  (h * inlink->w) > INT_MAX ||
274  (w * inlink->h) > INT_MAX)
275  av_log(ctx, AV_LOG_ERROR, "Rescaled value for width or height is too big.\n");
276 
277  outlink->w = w;
278  outlink->h = h;
279 
280  /* TODO: make algorithm configurable */
281 
282  scale->input_is_pal = desc->flags & PIX_FMT_PAL ||
283  desc->flags & PIX_FMT_PSEUDOPAL;
284  if (outfmt == AV_PIX_FMT_PAL8) outfmt = AV_PIX_FMT_BGR8;
285  scale->output_is_pal = av_pix_fmt_desc_get(outfmt)->flags & PIX_FMT_PAL ||
287 
288  if (scale->sws)
289  sws_freeContext(scale->sws);
290  if (inlink->w == outlink->w && inlink->h == outlink->h &&
291  inlink->format == outlink->format)
292  scale->sws = NULL;
293  else {
294  scale->sws = sws_getContext(inlink ->w, inlink ->h, inlink ->format,
295  outlink->w, outlink->h, outfmt,
296  scale->flags, NULL, NULL, NULL);
297  if (scale->isws[0])
298  sws_freeContext(scale->isws[0]);
299  scale->isws[0] = sws_getContext(inlink ->w, inlink ->h/2, inlink ->format,
300  outlink->w, outlink->h/2, outfmt,
301  scale->flags, NULL, NULL, NULL);
302  if (scale->isws[1])
303  sws_freeContext(scale->isws[1]);
304  scale->isws[1] = sws_getContext(inlink ->w, inlink ->h/2, inlink ->format,
305  outlink->w, outlink->h/2, outfmt,
306  scale->flags, NULL, NULL, NULL);
307  if (!scale->sws || !scale->isws[0] || !scale->isws[1])
308  return AVERROR(EINVAL);
309  }
310 
311  if (inlink->sample_aspect_ratio.num){
312  outlink->sample_aspect_ratio = av_mul_q((AVRational){outlink->h * inlink->w, outlink->w * inlink->h}, inlink->sample_aspect_ratio);
313  } else
314  outlink->sample_aspect_ratio = inlink->sample_aspect_ratio;
315 
316  av_log(ctx, AV_LOG_VERBOSE, "w:%d h:%d fmt:%s sar:%d/%d -> w:%d h:%d fmt:%s sar:%d/%d flags:0x%0x\n",
317  inlink ->w, inlink ->h, av_get_pix_fmt_name( inlink->format),
319  outlink->w, outlink->h, av_get_pix_fmt_name(outlink->format),
320  outlink->sample_aspect_ratio.num, outlink->sample_aspect_ratio.den,
321  scale->flags);
322  return 0;
323 
324 fail:
326  "Error when evaluating the expression '%s'.\n"
327  "Maybe the expression for out_w:'%s' or for out_h:'%s' is self-referencing.\n",
328  expr, scale->w_expr, scale->h_expr);
329  return ret;
330 }
331 
332 static int scale_slice(AVFilterLink *link, AVFilterBufferRef *out_buf, AVFilterBufferRef *cur_pic, struct SwsContext *sws, int y, int h, int mul, int field)
333 {
334  ScaleContext *scale = link->dst->priv;
335  const uint8_t *in[4];
336  uint8_t *out[4];
337  int in_stride[4],out_stride[4];
338  int i;
339 
340  for(i=0; i<4; i++){
341  int vsub= ((i+1)&2) ? scale->vsub : 0;
342  in_stride[i] = cur_pic->linesize[i] * mul;
343  out_stride[i] = out_buf->linesize[i] * mul;
344  in[i] = cur_pic->data[i] + ((y>>vsub)+field) * cur_pic->linesize[i];
345  out[i] = out_buf->data[i] + field * out_buf->linesize[i];
346  }
347  if(scale->input_is_pal)
348  in[1] = cur_pic->data[1];
349  if(scale->output_is_pal)
350  out[1] = out_buf->data[1];
351 
352  return sws_scale(sws, in, in_stride, y/mul, h,
353  out,out_stride);
354 }
355 
357 {
358  ScaleContext *scale = link->dst->priv;
359  AVFilterLink *outlink = link->dst->outputs[0];
361  const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(link->format);
362  char buf[32];
363 
364  if( in->video->w != link->w
365  || in->video->h != link->h
366  || in->format != link->format) {
367  int ret;
368  snprintf(buf, sizeof(buf)-1, "%d", outlink->w);
369  av_opt_set(scale, "w", buf, 0);
370  snprintf(buf, sizeof(buf)-1, "%d", outlink->h);
371  av_opt_set(scale, "h", buf, 0);
372 
373  link->dst->inputs[0]->format = in->format;
374  link->dst->inputs[0]->w = in->video->w;
375  link->dst->inputs[0]->h = in->video->h;
376 
377  if ((ret = config_props(outlink)) < 0)
378  return ret;
379  }
380 
381  if (!scale->sws)
382  return ff_filter_frame(outlink, in);
383 
384  scale->hsub = desc->log2_chroma_w;
385  scale->vsub = desc->log2_chroma_h;
386 
387  out = ff_get_video_buffer(outlink, AV_PERM_WRITE|AV_PERM_ALIGN, outlink->w, outlink->h);
388  if (!out) {
390  return AVERROR(ENOMEM);
391  }
392 
394  out->video->w = outlink->w;
395  out->video->h = outlink->h;
396 
397  if(scale->output_is_pal)
398  avpriv_set_systematic_pal2((uint32_t*)out->data[1], outlink->format == AV_PIX_FMT_PAL8 ? AV_PIX_FMT_BGR8 : outlink->format);
399 
401  (int64_t)in->video->sample_aspect_ratio.num * outlink->h * link->w,
402  (int64_t)in->video->sample_aspect_ratio.den * outlink->w * link->h,
403  INT_MAX);
404 
405  if(scale->interlaced>0 || (scale->interlaced<0 && in->video->interlaced)){
406  scale_slice(link, out, in, scale->isws[0], 0, (link->h+1)/2, 2, 0);
407  scale_slice(link, out, in, scale->isws[1], 0, link->h /2, 2, 1);
408  }else{
409  scale_slice(link, out, in, scale->sws, 0, link->h, 1, 0);
410  }
411 
413  return ff_filter_frame(outlink, out);
414 }
415 
417  {
418  .name = "default",
419  .type = AVMEDIA_TYPE_VIDEO,
420  .filter_frame = filter_frame,
421  .min_perms = AV_PERM_READ,
422  },
423  { NULL }
424 };
425 
427  {
428  .name = "default",
429  .type = AVMEDIA_TYPE_VIDEO,
430  .config_props = config_props,
431  },
432  { NULL }
433 };
434 
436  .name = "scale",
437  .description = NULL_IF_CONFIG_SMALL("Scale the input video to width:height size and/or convert the image format."),
438 
439  .init = init,
440  .uninit = uninit,
441 
442  .query_formats = query_formats,
443 
444  .priv_size = sizeof(ScaleContext),
445 
446  .inputs = avfilter_vf_scale_inputs,
447  .outputs = avfilter_vf_scale_outputs,
448  .priv_class = &scale_class,
449 };