/* *  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. */ // Decode With Drops Example// =========================//// This is an example utility which drops a series of frames, as specified// on the command line. This is useful for observing the error recovery// features of the codec.//// Usage// -----// This example adds a single argument to the `simple_decoder` example,// which specifies the range or pattern of frames to drop. The parameter is// parsed as follows://// Dropping A Range Of Frames// --------------------------// To drop a range of frames, specify the starting frame and the ending// frame to drop, separated by a dash. The following command will drop// frames 5 through 10 (base 1).////  $ ./decode_with_drops in.ivf out.i420 5-10////// Dropping A Pattern Of Frames// ----------------------------// To drop a pattern of frames, specify the number of frames to drop and// the number of frames after which to repeat the pattern, separated by// a forward-slash. The following command will drop 3 of 7 frames.// Specifically, it will decode 4 frames, then drop 3 frames, and then// repeat.////  $ ./decode_with_drops in.ivf out.i420 3/7////// Extra Variables// ---------------// This example maintains the pattern passed on the command line in the// `n`, `m`, and `is_range` variables:////// Making The Drop Decision// ------------------------// The example decides whether to drop the frame based on the current// frame number, immediately before decoding the frame. #include <stdio.h>#include <stdlib.h>#include <string.h> #include "vpx/vp8dx.h"#include "vpx/vpx_decoder.h" #include "../tools_common.h"#include "../video_reader.h"#include "./vpx_config.h" static const char *exec_name; void usage_exit(void) {  fprintf(stderr, "Usage: %s <infile> <outfile> <N-M|N/M>\n", exec_name);  exit(EXIT_FAILURE);} int main(int argc, char **argv) {  int frame_cnt = 0;  FILE *outfile = NULL;  vpx_codec_ctx_t codec;  const VpxInterface *decoder = NULL;  VpxVideoReader *reader = NULL;  const VpxVideoInfo *info = NULL;  int n = 0;  int m = 0;  int is_range = 0;  char *nptr = NULL;   exec_name = argv[0];   if (argc != 4) 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]);   n = (int)strtol(argv[3], &nptr, 0);  m = (int)strtol(nptr + 1, NULL, 0);  is_range = (*nptr == '-');  if (!n || !m || (*nptr != '-' && *nptr != '/'))    die("Couldn't parse pattern %s.\n", argv[3]);   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("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;    int skip;    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.");     ++frame_cnt;     skip = (is_range && frame_cnt >= n && frame_cnt <= m) ||           (!is_range && m - (frame_cnt - 1) % m <= n);     if (!skip) {      putc('.', stdout);       while ((img = vpx_codec_get_frame(&codec, &iter)) != NULL)        vpx_img_write(img, outfile);    } else {      putc('X', stdout);    }     fflush(stdout);  }   printf("Processed %d frames.\n", frame_cnt);  if (vpx_codec_destroy(&codec)) die_codec(&codec, "Failed to destroy codec.");   printf("Play: ffplay -f rawvideo -pix_fmt yuv420p -s %dx%d %s\n",         info->frame_width, info->frame_height, argv[2]);   vpx_video_reader_close(reader);  fclose(outfile);   return EXIT_SUCCESS;}