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