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