1 /*
2 * Copyright (c) 2012 Stefano Sabatini
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a copy
5 * of this software and associated documentation files (the "Software"), to deal
6 * in the Software without restriction, including without limitation the rights
7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8 * copies of the Software, and to permit persons to whom the Software is
9 * furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
20 * THE SOFTWARE.
21 */
22
23 /**
24 * @file
25 * libswscale API use example.
26 * @example scaling_video.c
27 */
28
29 #include <libavutil/imgutils.h>
30 #include <libavutil/parseutils.h>
31 #include <libswscale/swscale.h>
32
fill_yuv_image(uint8_t * data[4],int linesize[4],int width,int height,int frame_index)33 static void fill_yuv_image(uint8_t *data[4], int linesize[4],
34 int width, int height, int frame_index)
35 {
36 int x, y;
37
38 /* Y */
39 for (y = 0; y < height; y++)
40 for (x = 0; x < width; x++)
41 data[0][y * linesize[0] + x] = x + y + frame_index * 3;
42
43 /* Cb and Cr */
44 for (y = 0; y < height / 2; y++) {
45 for (x = 0; x < width / 2; x++) {
46 data[1][y * linesize[1] + x] = 128 + y + frame_index * 2;
47 data[2][y * linesize[2] + x] = 64 + x + frame_index * 5;
48 }
49 }
50 }
51
main(int argc,char ** argv)52 int main(int argc, char **argv)
53 {
54 uint8_t *src_data[4], *dst_data[4];
55 int src_linesize[4], dst_linesize[4];
56 int src_w = 320, src_h = 240, dst_w, dst_h;
57 enum AVPixelFormat src_pix_fmt = AV_PIX_FMT_YUV420P, dst_pix_fmt = AV_PIX_FMT_RGB24;
58 const char *dst_size = NULL;
59 const char *dst_filename = NULL;
60 FILE *dst_file;
61 int dst_bufsize;
62 struct SwsContext *sws_ctx;
63 int i, ret;
64
65 if (argc != 3) {
66 fprintf(stderr, "Usage: %s output_file output_size\n"
67 "API example program to show how to scale an image with libswscale.\n"
68 "This program generates a series of pictures, rescales them to the given "
69 "output_size and saves them to an output file named output_file\n."
70 "\n", argv[0]);
71 exit(1);
72 }
73 dst_filename = argv[1];
74 dst_size = argv[2];
75
76 if (av_parse_video_size(&dst_w, &dst_h, dst_size) < 0) {
77 fprintf(stderr,
78 "Invalid size '%s', must be in the form WxH or a valid size abbreviation\n",
79 dst_size);
80 exit(1);
81 }
82
83 dst_file = fopen(dst_filename, "wb");
84 if (!dst_file) {
85 fprintf(stderr, "Could not open destination file %s\n", dst_filename);
86 exit(1);
87 }
88
89 /* create scaling context */
90 sws_ctx = sws_getContext(src_w, src_h, src_pix_fmt,
91 dst_w, dst_h, dst_pix_fmt,
92 SWS_BILINEAR, NULL, NULL, NULL);
93 if (!sws_ctx) {
94 fprintf(stderr,
95 "Impossible to create scale context for the conversion "
96 "fmt:%s s:%dx%d -> fmt:%s s:%dx%d\n",
97 av_get_pix_fmt_name(src_pix_fmt), src_w, src_h,
98 av_get_pix_fmt_name(dst_pix_fmt), dst_w, dst_h);
99 ret = AVERROR(EINVAL);
100 goto end;
101 }
102
103 /* allocate source and destination image buffers */
104 if ((ret = av_image_alloc(src_data, src_linesize,
105 src_w, src_h, src_pix_fmt, 16)) < 0) {
106 fprintf(stderr, "Could not allocate source image\n");
107 goto end;
108 }
109
110 /* buffer is going to be written to rawvideo file, no alignment */
111 if ((ret = av_image_alloc(dst_data, dst_linesize,
112 dst_w, dst_h, dst_pix_fmt, 1)) < 0) {
113 fprintf(stderr, "Could not allocate destination image\n");
114 goto end;
115 }
116 dst_bufsize = ret;
117
118 for (i = 0; i < 100; i++) {
119 /* generate synthetic video */
120 fill_yuv_image(src_data, src_linesize, src_w, src_h, i);
121
122 /* convert to destination format */
123 sws_scale(sws_ctx, (const uint8_t * const*)src_data,
124 src_linesize, 0, src_h, dst_data, dst_linesize);
125
126 /* write scaled image to file */
127 fwrite(dst_data[0], 1, dst_bufsize, dst_file);
128 }
129
130 fprintf(stderr, "Scaling succeeded. Play the output file with the command:\n"
131 "ffplay -f rawvideo -pix_fmt %s -video_size %dx%d %s\n",
132 av_get_pix_fmt_name(dst_pix_fmt), dst_w, dst_h, dst_filename);
133
134 end:
135 fclose(dst_file);
136 av_freep(&src_data[0]);
137 av_freep(&dst_data[0]);
138 sws_freeContext(sws_ctx);
139 return ret < 0;
140 }
141