tor-browser

decode_to_md5.c (4015B)

---

/*
* Copyright (c) 2016, Alliance for Open Media. All rights reserved.
*
* This source code is subject to the terms of the BSD 2 Clause License and
* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
* was not distributed with this source code in the LICENSE file, you can
* obtain it at www.aomedia.org/license/software. If the Alliance for Open
* Media Patent License 1.0 was not distributed with this source code in the
* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
*/

// 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 "aom/aom_decoder.h"
#include "aom/aomdx.h"
#include "common/md5_utils.h"
#include "common/tools_common.h"
#include "common/video_reader.h"

static void get_image_md5(const aom_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;
 AvxVideoReader *reader = NULL;
 const AvxVideoInfo *info = NULL;

 exec_name = argv[0];

 if (argc != 3) die("Invalid number of arguments.");

 reader = aom_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 = aom_video_reader_get_info(reader);

 aom_codec_iface_t *decoder = get_aom_decoder_by_fourcc(info->codec_fourcc);
 if (!decoder) die("Unknown input codec.");

 printf("Using %s\n", aom_codec_iface_name(decoder));

 aom_codec_ctx_t codec;
 if (aom_codec_dec_init(&codec, decoder, NULL, 0))
   die("Failed to initialize decoder");

 while (aom_video_reader_read_frame(reader)) {
   aom_codec_iter_t iter = NULL;
   aom_image_t *img = NULL;
   size_t frame_size = 0;
   const unsigned char *frame =
       aom_video_reader_get_frame(reader, &frame_size);
   if (aom_codec_decode(&codec, frame, frame_size, NULL))
     die_codec(&codec, "Failed to decode frame");

   while ((img = aom_codec_get_frame(&codec, &iter)) != NULL) {
     unsigned char digest[16];

     get_image_md5(img, digest);
     print_md5(outfile, digest);
     fprintf(outfile, "  img-%ux%u-%04d.i420\n", img->d_w, img->d_h,
             ++frame_cnt);
   }
 }

 printf("Processed %d frames.\n", frame_cnt);
 if (aom_codec_destroy(&codec)) die_codec(&codec, "Failed to destroy codec.");

 aom_video_reader_close(reader);

 fclose(outfile);
 return EXIT_SUCCESS;
}