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      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 #define VPX_CODEC_DISABLE_COMPAT 1
     60 
     61 #include "vpx/vp8dx.h"
     62 #include "vpx/vpx_decoder.h"
     63 
     64 #include "./tools_common.h"
     65 #include "./video_reader.h"
     66 #include "./vpx_config.h"
     67 
     68 static const char *exec_name;
     69 
     70 void usage_exit() {
     71   fprintf(stderr, "Usage: %s <infile> <outfile> <N-M|N/M>\n", exec_name);
     72   exit(EXIT_FAILURE);
     73 }
     74 
     75 int main(int argc, char **argv) {
     76   int frame_cnt = 0;
     77   FILE *outfile = NULL;
     78   vpx_codec_ctx_t codec;
     79   const VpxInterface *decoder = NULL;
     80   VpxVideoReader *reader = NULL;
     81   const VpxVideoInfo *info = NULL;
     82   int n = 0;
     83   int m = 0;
     84   int is_range = 0;
     85   char *nptr = NULL;
     86 
     87   exec_name = argv[0];
     88 
     89   if (argc != 4)
     90     die("Invalid number of arguments.");
     91 
     92   reader = vpx_video_reader_open(argv[1]);
     93   if (!reader)
     94     die("Failed to open %s for reading.", argv[1]);
     95 
     96   if (!(outfile = fopen(argv[2], "wb")))
     97     die("Failed to open %s for writing.", argv[2]);
     98 
     99   n = strtol(argv[3], &nptr, 0);
    100   m = strtol(nptr + 1, NULL, 0);
    101   is_range = (*nptr == '-');
    102   if (!n || !m || (*nptr != '-' && *nptr != '/'))
    103     die("Couldn't parse pattern %s.\n", argv[3]);
    104 
    105   info = vpx_video_reader_get_info(reader);
    106 
    107   decoder = get_vpx_decoder_by_fourcc(info->codec_fourcc);
    108   if (!decoder)
    109     die("Unknown input codec.");
    110 
    111   printf("Using %s\n", vpx_codec_iface_name(decoder->interface()));
    112 
    113   if (vpx_codec_dec_init(&codec, decoder->interface(), NULL, 0))
    114     die_codec(&codec, "Failed to initialize decoder.");
    115 
    116   while (vpx_video_reader_read_frame(reader)) {
    117     vpx_codec_iter_t iter = NULL;
    118     vpx_image_t *img = NULL;
    119     size_t frame_size = 0;
    120     int skip;
    121     const unsigned char *frame = vpx_video_reader_get_frame(reader,
    122                                                             &frame_size);
    123     if (vpx_codec_decode(&codec, frame, (unsigned int)frame_size, NULL, 0))
    124       die_codec(&codec, "Failed to decode frame.");
    125 
    126     ++frame_cnt;
    127 
    128     skip = (is_range && frame_cnt >= n && frame_cnt <= m) ||
    129            (!is_range && m - (frame_cnt - 1) % m <= n);
    130 
    131     if (!skip) {
    132       putc('.', stdout);
    133 
    134       while ((img = vpx_codec_get_frame(&codec, &iter)) != NULL)
    135         vpx_img_write(img, outfile);
    136     } else {
    137       putc('X', stdout);
    138     }
    139 
    140     fflush(stdout);
    141   }
    142 
    143   printf("Processed %d frames.\n", frame_cnt);
    144   if (vpx_codec_destroy(&codec))
    145     die_codec(&codec, "Failed to destroy codec.");
    146 
    147   printf("Play: ffplay -f rawvideo -pix_fmt yuv420p -s %dx%d %s\n",
    148          info->frame_width, info->frame_height, argv[2]);
    149 
    150   vpx_video_reader_close(reader);
    151   fclose(outfile);
    152 
    153   return EXIT_SUCCESS;
    154 }
    155