/* *  Copyright (c) 2010 The WebM project authors. All Rights Reserved. * *  Use of this source code is governed by a BSD-style license *  that can be found in the LICENSE file in the root of the source *  tree. An additional intellectual property rights grant can be found *  in the file PATENTS.  All contributing project authors may *  be found in the AUTHORS file in the root of the source tree. */ // Frame-by-frame MD5 Checksum// ===========================//// This example builds upon the simple decoder loop to show how checksums// of the decoded output can be generated. These are used for validating// decoder implementations against the reference implementation, for example.//// MD5 algorithm// -------------// The Message-Digest 5 (MD5) is a well known hash function. We have provided// an implementation derived from the RSA Data Security, Inc. MD5 Message-Digest// Algorithm for your use. Our implmentation only changes the interface of this// reference code. You must include the `md5_utils.h` header for access to these// functions.//// Processing The Decoded Data// ---------------------------// Each row of the image is passed to the MD5 accumulator. First the Y plane// is processed, then U, then V. It is important to honor the image's `stride`// values. #include <stdio.h>#include <stdlib.h>#include <string.h> #include "vpx/vp8dx.h"#include "vpx/vpx_decoder.h" #include "../md5_utils.h"#include "../tools_common.h"#include "../video_reader.h"#include "./vpx_config.h" static void get_image_md5(const vpx_image_t *img, unsigned char digest[16]) {  int plane, y;  MD5Context md5;   MD5Init(&md5);   for (plane = 0; plane < 3; ++plane) {    const unsigned char *buf = img->planes[plane];    const int stride = img->stride[plane];    const int w = plane ? (img->d_w + 1) >> 1 : img->d_w;    const int h = plane ? (img->d_h + 1) >> 1 : img->d_h;     for (y = 0; y < h; ++y) {      MD5Update(&md5, buf, w);      buf += stride;    }  }   MD5Final(digest, &md5);} static void print_md5(FILE *stream, unsigned char digest[16]) {  int i;   for (i = 0; i < 16; ++i) fprintf(stream, "%02x", digest[i]);} static const char *exec_name; void usage_exit(void) {  fprintf(stderr, "Usage: %s <infile> <outfile>\n", exec_name);  exit(EXIT_FAILURE);} int main(int argc, char **argv) {  int frame_cnt = 0;  FILE *outfile = NULL;  vpx_codec_ctx_t codec;  VpxVideoReader *reader = NULL;  const VpxVideoInfo *info = NULL;  const VpxInterface *decoder = NULL;   exec_name = argv[0];   if (argc != 3) die("Invalid number of arguments.");   reader = vpx_video_reader_open(argv[1]);  if (!reader) die("Failed to open %s for reading.", argv[1]);   if (!(outfile = fopen(argv[2], "wb")))    die("Failed to open %s for writing.", argv[2]);   info = vpx_video_reader_get_info(reader);   decoder = get_vpx_decoder_by_fourcc(info->codec_fourcc);  if (!decoder) die("Unknown input codec.");   printf("Using %s\n", vpx_codec_iface_name(decoder->codec_interface()));   if (vpx_codec_dec_init(&codec, decoder->codec_interface(), NULL, 0))    die_codec(&codec, "Failed to initialize decoder");   while (vpx_video_reader_read_frame(reader)) {    vpx_codec_iter_t iter = NULL;    vpx_image_t *img = NULL;    size_t frame_size = 0;    const unsigned char *frame =        vpx_video_reader_get_frame(reader, &frame_size);    if (vpx_codec_decode(&codec, frame, (unsigned int)frame_size, NULL, 0))      die_codec(&codec, "Failed to decode frame");     while ((img = vpx_codec_get_frame(&codec, &iter)) != NULL) {      unsigned char digest[16];       get_image_md5(img, digest);      print_md5(outfile, digest);      fprintf(outfile, "  img-%dx%d-%04d.i420\n", img->d_w, img->d_h,              ++frame_cnt);    }  }   printf("Processed %d frames.\n", frame_cnt);  if (vpx_codec_destroy(&codec)) die_codec(&codec, "Failed to destroy codec.");   vpx_video_reader_close(reader);   fclose(outfile);  return EXIT_SUCCESS;}