text: /*
   * Copyright (c) 2012 Stefano Sabatini
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  
  /**
   * @file
   * libswscale API use example.
   * @example scaling_video.c
   */
  
  #include <libavutil/imgutils.h>
  #include <libavutil/parseutils.h>
  #include <libswscale/swscale.h>
  
  static void fill_yuv_image(uint8_t *data[4], int linesize[4],
                             int width, int height, int frame_index)
  {
      int x, y;
  
      /* Y */
      for (y = 0; y < height; y++)
          for (x = 0; x < width; x++)
              data[0][y * linesize[0] + x] = x + y + frame_index * 3;
  
      /* Cb and Cr */
      for (y = 0; y < height / 2; y++) {
          for (x = 0; x < width / 2; x++) {
              data[1][y * linesize[1] + x] = 128 + y + frame_index * 2;
              data[2][y * linesize[2] + x] = 64 + x + frame_index * 5;
          }
      }
  }
  
  int main(int argc, char **argv)
  {
      uint8_t *src_data[4], *dst_data[4];
      int src_linesize[4], dst_linesize[4];
      int src_w = 320, src_h = 240, dst_w, dst_h;
      enum AVPixelFormat src_pix_fmt = AV_PIX_FMT_YUV420P, dst_pix_fmt = AV_PIX_FMT_RGB24;
      const char *dst_size = NULL;
      const char *dst_filename = NULL;
      FILE *dst_file;
      int dst_bufsize;
      struct SwsContext *sws_ctx;
      int i, ret;
  
      if (argc != 3) {
          fprintf(stderr, "Usage: %s output_file output_size\n"
                  "API example program to show how to scale an image with libswscale.\n"
                  "This program generates a series of pictures, rescales them to the given "
                  "output_size and saves them to an output file named output_file\n."
                  "\n", argv[0]);
          exit(1);
      }
      dst_filename = argv[1];
      dst_size     = argv[2];
  
      if (av_parse_video_size(&dst_w, &dst_h, dst_size) < 0) {
          fprintf(stderr,
                  "Invalid size '%s', must be in the form WxH or a valid size abbreviation\n",
                  dst_size);
          exit(1);
      }
  
      dst_file = fopen(dst_filename, "wb");
      if (!dst_file) {
          fprintf(stderr, "Could not open destination file %s\n", dst_filename);
          exit(1);
      }
  
      /* create scaling context */
      sws_ctx = sws_getContext(src_w, src_h, src_pix_fmt,
                               dst_w, dst_h, dst_pix_fmt,
                               SWS_BILINEAR, NULL, NULL, NULL);
      if (!sws_ctx) {
          fprintf(stderr,
                  "Impossible to create scale context for the conversion "
                  "fmt:%s s:%dx%d -> fmt:%s s:%dx%d\n",
                  av_get_pix_fmt_name(src_pix_fmt), src_w, src_h,
                  av_get_pix_fmt_name(dst_pix_fmt), dst_w, dst_h);
          ret = AVERROR(EINVAL);
          goto end;
      }
  
      /* allocate source and destination image buffers */
      if ((ret = av_image_alloc(src_data, src_linesize,
                                src_w, src_h, src_pix_fmt, 16)) < 0) {
          fprintf(stderr, "Could not allocate source image\n");
          goto end;
      }
  
      /* buffer is going to be written to rawvideo file, no alignment */
      if ((ret = av_image_alloc(dst_data, dst_linesize,
                                dst_w, dst_h, dst_pix_fmt, 1)) < 0) {
          fprintf(stderr, "Could not allocate destination image\n");
          goto end;
      }
      dst_bufsize = ret;
  
      for (i = 0; i < 100; i++) {
          /* generate synthetic video */
          fill_yuv_image(src_data, src_linesize, src_w, src_h, i);
  
          /* convert to destination format */
          sws_scale(sws_ctx, (const uint8_t * const*)src_data,
                    src_linesize, 0, src_h, dst_data, dst_linesize);
  
          /* write scaled image to file */
          fwrite(dst_data[0], 1, dst_bufsize, dst_file);
      }
  
      fprintf(stderr, "Scaling succeeded. Play the output file with the command:\n"
             "ffplay -f rawvideo -pix_fmt %s -video_size %dx%d %s\n",
             av_get_pix_fmt_name(dst_pix_fmt), dst_w, dst_h, dst_filename);
  
  end:
      fclose(dst_file);
      av_freep(&src_data[0]);
      av_freep(&dst_data[0]);
      sws_freeContext(sws_ctx);
      return ret < 0;
  }
  