examples/decode_with_drops.c

   1 /*
   2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
   3  *
   4  *  Use of this source code is governed by a BSD-style license
   5  *  that can be found in the LICENSE file in the root of the source
   6  *  tree. An additional intellectual property rights grant can be found
   7  *  in the file PATENTS.  All contributing project authors may
   8  *  be found in the AUTHORS file in the root of the source tree.
   9  */
  10
  11 // Decode With Drops Example
  12 // =========================
  13 //
  14 // This is an example utility which drops a series of frames, as specified
  15 // on the command line. This is useful for observing the error recovery
  16 // features of the codec.
  17 //
  18 // Usage
  19 // -----
  20 // This example adds a single argument to the `simple_decoder` example,
  21 // which specifies the range or pattern of frames to drop. The parameter is
  22 // parsed as follows:
  23 //
  24 // Dropping A Range Of Frames
  25 // --------------------------
  26 // To drop a range of frames, specify the starting frame and the ending
  27 // frame to drop, separated by a dash. The following command will drop
  28 // frames 5 through 10 (base 1).
  29 //
  30 //  $ ./decode_with_drops in.ivf out.i420 5-10
  31 //
  32 //
  33 // Dropping A Pattern Of Frames
  34 // ----------------------------
  35 // To drop a pattern of frames, specify the number of frames to drop and
  36 // the number of frames after which to repeat the pattern, separated by
  37 // a forward-slash. The following command will drop 3 of 7 frames.
  38 // Specifically, it will decode 4 frames, then drop 3 frames, and then
  39 // repeat.
  40 //
  41 //  $ ./decode_with_drops in.ivf out.i420 3/7
  42 //
  43 //
  44 // Extra Variables
  45 // ---------------
  46 // This example maintains the pattern passed on the command line in the
  47 // `n`, `m`, and `is_range` variables:
  48 //
  49 //
  50 // Making The Drop Decision
  51 // ------------------------
  52 // The example decides whether to drop the frame based on the current
  53 // frame number, immediately before decoding the frame.
  54
  55 #include <stdio.h>
  56 #include <stdlib.h>
  57 #include <string.h>
  58
  59 #include "vpx/vp8dx.h"
  60 #include "vpx/vpx_decoder.h"
  61
  62 #include "../tools_common.h"
  63 #include "../video_reader.h"
  64 #include "./vpx_config.h"
  65
  66 static const char *exec_name;
  67
  68 void usage_exit(void) {
  69   fprintf(stderr, "Usage: %s <infile> <outfile> <N-M|N/M>\n", exec_name);
  70   exit(EXIT_FAILURE);
  71 }
  72
  73 int main(int argc, char **argv) {
  74   int frame_cnt = 0;
  75   FILE *outfile = NULL;
  76   vpx_codec_ctx_t codec;
  77   const VpxInterface *decoder = NULL;
  78   VpxVideoReader *reader = NULL;
  79   const VpxVideoInfo *info = NULL;
  80   int n = 0;
  81   int m = 0;
  82   int is_range = 0;
  83   char *nptr = NULL;
  84
  85   exec_name = argv[0];
  86
  87   if (argc != 4)
  88     die("Invalid number of arguments.");
  89
  90   reader = vpx_video_reader_open(argv[1]);
  91   if (!reader)
  92     die("Failed to open %s for reading.", argv[1]);
  93
  94   if (!(outfile = fopen(argv[2], "wb")))
  95     die("Failed to open %s for writing.", argv[2]);
  96
  97   n = strtol(argv[3], &nptr, 0);
  98   m = strtol(nptr + 1, NULL, 0);
  99   is_range = (*nptr == '-');
 100   if (!n || !m || (*nptr != '-' && *nptr != '/'))
 101     die("Couldn't parse pattern %s.\n", argv[3]);
 102
 103   info = vpx_video_reader_get_info(reader);
 104
 105   decoder = get_vpx_decoder_by_fourcc(info->codec_fourcc);
 106   if (!decoder)
 107     die("Unknown input codec.");
 108
 109   printf("Using %s\n", vpx_codec_iface_name(decoder->codec_interface()));
 110
 111   if (vpx_codec_dec_init(&codec, decoder->codec_interface(), NULL, 0))
 112     die_codec(&codec, "Failed to initialize decoder.");
 113
 114   while (vpx_video_reader_read_frame(reader)) {
 115     vpx_codec_iter_t iter = NULL;
 116     vpx_image_t *img = NULL;
 117     size_t frame_size = 0;
 118     int skip;
 119     const unsigned char *frame = vpx_video_reader_get_frame(reader,
 120                                                             &frame_size);
 121     if (vpx_codec_decode(&codec, frame, (unsigned int)frame_size, NULL, 0))
 122       die_codec(&codec, "Failed to decode frame.");
 123
 124     ++frame_cnt;
 125
 126     skip = (is_range && frame_cnt >= n && frame_cnt <= m) ||
 127            (!is_range && m - (frame_cnt - 1) % m <= n);
 128
 129     if (!skip) {
 130       putc('.', stdout);
 131
 132       while ((img = vpx_codec_get_frame(&codec, &iter)) != NULL)
 133         vpx_img_write(img, outfile);
 134     } else {
 135       putc('X', stdout);
 136     }
 137
 138     fflush(stdout);
 139   }
 140
 141   printf("Processed %d frames.\n", frame_cnt);
 142   if (vpx_codec_destroy(&codec))
 143     die_codec(&codec, "Failed to destroy codec.");
 144
 145   printf("Play: ffplay -f rawvideo -pix_fmt yuv420p -s %dx%d %s\n",
 146          info->frame_width, info->frame_height, argv[2]);
 147
 148   vpx_video_reader_close(reader);
 149   fclose(outfile);
 150
 151   return EXIT_SUCCESS;
 152 }