/*
 * Copyright (c) 2021, Alliance for Open Media. All rights reserved
 *
 * This source code is subject to the terms of the BSD 3-Clause Clear License
 * and the Alliance for Open Media Patent License 1.0. If the BSD 3-Clause Clear
 * License was not distributed with this source code in the LICENSE file, you
 * can obtain it at aomedia.org/license/software-license/bsd-3-c-c/.  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
 * aomedia.org/license/patent-license/.
 */

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <limits.h>

#include "config/aom_config.h"

#if CONFIG_OS_SUPPORT
#if HAVE_UNISTD_H
#include <unistd.h>  // NOLINT
#elif !defined(STDOUT_FILENO)
#define STDOUT_FILENO 1
#endif
#endif

#include "aom/aom_decoder.h"
#include "aom/aomdx.h"
#include "aom_ports/aom_timer.h"
#include "aom_ports/mem_ops.h"
#include "common/args.h"
#include "common/ivfdec.h"
#include "common/md5_utils.h"
#include "common/obudec.h"
#include "common/tools_common.h"

#if CONFIG_WEBM_IO
#include "common/webmdec.h"
#endif

#include "common/rawenc.h"
#include "common/y4menc.h"

#if CONFIG_LIBYUV
#include "third_party/libyuv/include/libyuv/scale.h"
#endif

static const char *exec_name;

struct AvxDecInputContext {
  struct AvxInputContext *aom_input_ctx;
  struct ObuDecInputContext *obu_ctx;
  struct WebmInputContext *webm_ctx;
};

static const arg_def_t help =
    ARG_DEF(NULL, "help", 0, "Show usage options and exit");
static const arg_def_t looparg =
    ARG_DEF(NULL, "loops", 1, "Number of times to decode the file");
static const arg_def_t codecarg = ARG_DEF(NULL, "codec", 1, "Codec to use");
static const arg_def_t use_yv12 =
    ARG_DEF(NULL, "yv12", 0, "Output raw YV12 frames");
static const arg_def_t use_i420 =
    ARG_DEF(NULL, "i420", 0, "Output raw I420 frames");
static const arg_def_t flipuvarg =
    ARG_DEF(NULL, "flipuv", 0, "Flip the chroma planes in the output");
static const arg_def_t rawvideo =
    ARG_DEF(NULL, "rawvideo", 0, "Output raw YUV frames");
static const arg_def_t noblitarg =
    ARG_DEF(NULL, "noblit", 0, "Don't process the decoded frames");
static const arg_def_t progressarg =
    ARG_DEF(NULL, "progress", 0, "Show progress after each frame decodes");
static const arg_def_t limitarg =
    ARG_DEF(NULL, "limit", 1, "Stop decoding after n frames");
static const arg_def_t skiparg =
    ARG_DEF(NULL, "skip", 1, "Skip the first n input frames");
static const arg_def_t summaryarg =
    ARG_DEF(NULL, "summary", 0, "Show timing summary");
static const arg_def_t outputfile =
    ARG_DEF("o", "output", 1, "Output file name pattern (see below)");
static const arg_def_t threadsarg =
    ARG_DEF("t", "threads", 1, "Max threads to use");
static const arg_def_t verbosearg =
    ARG_DEF("v", "verbose", 0, "Show version string");
static const arg_def_t scalearg =
    ARG_DEF("S", "scale", 0, "Scale output frames uniformly");
static const arg_def_t continuearg =
    ARG_DEF("k", "keep-going", 0, "(debug) Continue decoding after error");
static const arg_def_t fb_arg =
    ARG_DEF(NULL, "frame-buffers", 1, "Number of frame buffers to use");
static const arg_def_t md5arg =
    ARG_DEF(NULL, "md5", 0, "Compute the MD5 sum of the decoded frame");
static const arg_def_t framestatsarg =
    ARG_DEF(NULL, "framestats", 1, "Output per-frame stats (.csv format)");
static const arg_def_t outbitdeptharg =
    ARG_DEF(NULL, "output-bit-depth", 1, "Output bit-depth for decoded frames");
static const arg_def_t isannexb =
    ARG_DEF(NULL, "annexb", 0, "Bitstream is in Annex-B format");
static const arg_def_t oppointarg = ARG_DEF(
    NULL, "oppoint", 1, "Select an operating point of a scalable bitstream");
static const arg_def_t outallarg = ARG_DEF(
    NULL, "all-layers", 0, "Output all decoded frames of a scalable bitstream");
static const arg_def_t skipfilmgrain =
    ARG_DEF(NULL, "skip-film-grain", 0, "Skip film grain application");

static const arg_def_t *all_args[] = {
  &help,       &codecarg,   &use_yv12,      &use_i420,      &flipuvarg,
  &rawvideo,   &noblitarg,  &progressarg,   &limitarg,      &skiparg,
  &summaryarg, &outputfile, &threadsarg,    &verbosearg,    &scalearg,
  &fb_arg,     &md5arg,     &framestatsarg, &continuearg,   &outbitdeptharg,
  &isannexb,   &oppointarg, &outallarg,     &skipfilmgrain, NULL
};

#if CONFIG_LIBYUV
static INLINE int libyuv_scale(aom_image_t *src, aom_image_t *dst,
                               FilterModeEnum mode) {
  if (src->fmt == AOM_IMG_FMT_I42016) {
    assert(dst->fmt == AOM_IMG_FMT_I42016);
    return I420Scale_16(
        (uint16_t *)src->planes[AOM_PLANE_Y], src->stride[AOM_PLANE_Y] / 2,
        (uint16_t *)src->planes[AOM_PLANE_U], src->stride[AOM_PLANE_U] / 2,
        (uint16_t *)src->planes[AOM_PLANE_V], src->stride[AOM_PLANE_V] / 2,
        src->d_w, src->d_h, (uint16_t *)dst->planes[AOM_PLANE_Y],
        dst->stride[AOM_PLANE_Y] / 2, (uint16_t *)dst->planes[AOM_PLANE_U],
        dst->stride[AOM_PLANE_U] / 2, (uint16_t *)dst->planes[AOM_PLANE_V],
        dst->stride[AOM_PLANE_V] / 2, dst->d_w, dst->d_h, mode);
  }
  assert(src->fmt == AOM_IMG_FMT_I420);
  assert(dst->fmt == AOM_IMG_FMT_I420);
  return I420Scale(src->planes[AOM_PLANE_Y], src->stride[AOM_PLANE_Y],
                   src->planes[AOM_PLANE_U], src->stride[AOM_PLANE_U],
                   src->planes[AOM_PLANE_V], src->stride[AOM_PLANE_V], src->d_w,
                   src->d_h, dst->planes[AOM_PLANE_Y], dst->stride[AOM_PLANE_Y],
                   dst->planes[AOM_PLANE_U], dst->stride[AOM_PLANE_U],
                   dst->planes[AOM_PLANE_V], dst->stride[AOM_PLANE_V], dst->d_w,
                   dst->d_h, mode);
}
#endif

static void show_help(FILE *fout, int shorthelp) {
  fprintf(fout, "Usage: %s <options> filename\n\n", exec_name);

  if (shorthelp) {
    fprintf(fout, "Use --help to see the full list of options.\n");
    return;
  }

  fprintf(fout, "Options:\n");
  arg_show_usage(fout, all_args);
  fprintf(fout,
          "\nOutput File Patterns:\n\n"
          "  The -o argument specifies the name of the file(s) to "
          "write to. If the\n  argument does not include any escape "
          "characters, the output will be\n  written to a single file. "
          "Otherwise, the filename will be calculated by\n  expanding "
          "the following escape characters:\n");
  fprintf(fout,
          "\n\t%%w   - Frame width"
          "\n\t%%h   - Frame height"
          "\n\t%%<n> - Frame number, zero padded to <n> places (1..9)"
          "\n\n  Pattern arguments are only supported in conjunction "
          "with the --yv12 and\n  --i420 options. If the -o option is "
          "not specified, the output will be\n  directed to stdout.\n");
  fprintf(fout, "\nIncluded decoders:\n\n");

  for (int i = 0; i < get_aom_decoder_count(); ++i) {
    aom_codec_iface_t *decoder = get_aom_decoder_by_index(i);
    fprintf(fout, "    %-6s - %s\n", get_short_name_by_aom_decoder(decoder),
            aom_codec_iface_name(decoder));
  }
}

void usage_exit(void) {
  show_help(stderr, 1);
  exit(EXIT_FAILURE);
}

static int raw_read_frame(FILE *infile, uint8_t **buffer, size_t *bytes_read,
                          size_t *buffer_size) {
  char raw_hdr[RAW_FRAME_HDR_SZ];
  size_t frame_size = 0;

  if (fread(raw_hdr, RAW_FRAME_HDR_SZ, 1, infile) != 1) {
    if (!feof(infile)) warn("Failed to read RAW frame size\n");
  } else {
    const size_t kCorruptFrameThreshold = 256 * 1024 * 1024;
    const size_t kFrameTooSmallThreshold = 256 * 1024;
    frame_size = mem_get_le32(raw_hdr);

    if (frame_size > kCorruptFrameThreshold) {
      warn("Read invalid frame size (%u)\n", (unsigned int)frame_size);
      frame_size = 0;
    }

    if (frame_size < kFrameTooSmallThreshold) {
      warn("Warning: Read invalid frame size (%u) - not a raw file?\n",
           (unsigned int)frame_size);
    }

    if (frame_size > *buffer_size) {
      uint8_t *new_buf = realloc(*buffer, 2 * frame_size);
      if (new_buf) {
        *buffer = new_buf;
        *buffer_size = 2 * frame_size;
      } else {
        warn("Failed to allocate compressed data buffer\n");
        frame_size = 0;
      }
    }
  }

  if (!feof(infile)) {
    if (fread(*buffer, 1, frame_size, infile) != frame_size) {
      warn("Failed to read full frame\n");
      return 1;
    }
    *bytes_read = frame_size;
  }

  return 0;
}

static int read_frame(struct AvxDecInputContext *input, uint8_t **buf,
                      size_t *bytes_in_buffer, size_t *buffer_size) {
  switch (input->aom_input_ctx->file_type) {
#if CONFIG_WEBM_IO
    case FILE_TYPE_WEBM:
      return webm_read_frame(input->webm_ctx, buf, bytes_in_buffer,
                             buffer_size);
#endif
    case FILE_TYPE_RAW:
      return raw_read_frame(input->aom_input_ctx->file, buf, bytes_in_buffer,
                            buffer_size);
    case FILE_TYPE_IVF:
      return ivf_read_frame(input->aom_input_ctx->file, buf, bytes_in_buffer,
                            buffer_size, NULL);
    case FILE_TYPE_OBU:
      return obudec_read_temporal_unit(input->obu_ctx, buf, bytes_in_buffer,
                                       buffer_size);
    default: return 1;
  }
}

static int file_is_raw(struct AvxInputContext *input) {
  uint8_t buf[32];
  int is_raw = 0;
  aom_codec_stream_info_t si;
  memset(&si, 0, sizeof(si));

  if (fread(buf, 1, 32, input->file) == 32) {
    int i;

    if (mem_get_le32(buf) < 256 * 1024 * 1024) {
      for (i = 0; i < get_aom_decoder_count(); ++i) {
        aom_codec_iface_t *decoder = get_aom_decoder_by_index(i);
        if (!aom_codec_peek_stream_info(decoder, buf + 4, 32 - 4, &si)) {
          is_raw = 1;
          input->fourcc = get_fourcc_by_aom_decoder(decoder);
          input->width = si.w;
          input->height = si.h;
          input->framerate.numerator = 30;
          input->framerate.denominator = 1;
          break;
        }
      }
    }
  }

  rewind(input->file);
  return is_raw;
}

static void show_progress(int frame_in, int frame_out, uint64_t dx_time) {
  fprintf(stderr,
          "%d decoded frames/%d showed frames in %" PRId64 " us (%.2f fps)\r",
          frame_in, frame_out, dx_time,
          (double)frame_out * 1000000.0 / (double)dx_time);
}

struct ExternalFrameBuffer {
  uint8_t *data;
  size_t size;
  int in_use;
};

struct ExternalFrameBufferList {
  int num_external_frame_buffers;
  struct ExternalFrameBuffer *ext_fb;
};

// Callback used by libaom to request an external frame buffer. |cb_priv|
// Application private data passed into the set function. |min_size| is the
// minimum size in bytes needed to decode the next frame. |fb| pointer to the
// frame buffer.
static int get_av1_frame_buffer(void *cb_priv, size_t min_size,
                                aom_codec_frame_buffer_t *fb) {
  int i;
  struct ExternalFrameBufferList *const ext_fb_list =
      (struct ExternalFrameBufferList *)cb_priv;
  if (ext_fb_list == NULL) return -1;

  // Find a free frame buffer.
  for (i = 0; i < ext_fb_list->num_external_frame_buffers; ++i) {
    if (!ext_fb_list->ext_fb[i].in_use) break;
  }

  if (i == ext_fb_list->num_external_frame_buffers) return -1;

  if (ext_fb_list->ext_fb[i].size < min_size) {
    free(ext_fb_list->ext_fb[i].data);
    ext_fb_list->ext_fb[i].data = (uint8_t *)calloc(min_size, sizeof(uint8_t));
    if (!ext_fb_list->ext_fb[i].data) return -1;

    ext_fb_list->ext_fb[i].size = min_size;
  }

  fb->data = ext_fb_list->ext_fb[i].data;
  fb->size = ext_fb_list->ext_fb[i].size;
  ext_fb_list->ext_fb[i].in_use = 1;

  // Set the frame buffer's private data to point at the external frame buffer.
  fb->priv = &ext_fb_list->ext_fb[i];
  return 0;
}

// Callback used by libaom when there are no references to the frame buffer.
// |cb_priv| user private data passed into the set function. |fb| pointer
// to the frame buffer.
static int release_av1_frame_buffer(void *cb_priv,
                                    aom_codec_frame_buffer_t *fb) {
  struct ExternalFrameBuffer *const ext_fb =
      (struct ExternalFrameBuffer *)fb->priv;
  (void)cb_priv;
  ext_fb->in_use = 0;
  return 0;
}

static void generate_filename(const char *pattern, char *out, size_t q_len,
                              unsigned int d_w, unsigned int d_h,
                              unsigned int frame_in) {
  const char *p = pattern;
  char *q = out;

  do {
    char *next_pat = strchr(p, '%');

    if (p == next_pat) {
      size_t pat_len;

      /* parse the pattern */
      q[q_len - 1] = '\0';
      switch (p[1]) {
        case 'w': snprintf(q, q_len - 1, "%d", d_w); break;
        case 'h': snprintf(q, q_len - 1, "%d", d_h); break;
        case '1': snprintf(q, q_len - 1, "%d", frame_in); break;
        case '2': snprintf(q, q_len - 1, "%02d", frame_in); break;
        case '3': snprintf(q, q_len - 1, "%03d", frame_in); break;
        case '4': snprintf(q, q_len - 1, "%04d", frame_in); break;
        case '5': snprintf(q, q_len - 1, "%05d", frame_in); break;
        case '6': snprintf(q, q_len - 1, "%06d", frame_in); break;
        case '7': snprintf(q, q_len - 1, "%07d", frame_in); break;
        case '8': snprintf(q, q_len - 1, "%08d", frame_in); break;
        case '9': snprintf(q, q_len - 1, "%09d", frame_in); break;
        default: die("Unrecognized pattern %%%c\n", p[1]); break;
      }

      pat_len = strlen(q);
      if (pat_len >= q_len - 1) die("Output filename too long.\n");
      q += pat_len;
      p += 2;
      q_len -= pat_len;
    } else {
      size_t copy_len;

      /* copy the next segment */
      if (!next_pat)
        copy_len = strlen(p);
      else
        copy_len = next_pat - p;

      if (copy_len >= q_len - 1) die("Output filename too long.\n");

      memcpy(q, p, copy_len);
      q[copy_len] = '\0';
      q += copy_len;
      p += copy_len;
      q_len -= copy_len;
    }
  } while (*p);
}

static int is_single_file(const char *outfile_pattern) {
  const char *p = outfile_pattern;

  do {
    p = strchr(p, '%');
    if (p && p[1] >= '1' && p[1] <= '9')
      return 0;  // pattern contains sequence number, so it's not unique
    if (p) p++;
  } while (p);

  return 1;
}

static void print_md5(unsigned char digest[16], const char *filename) {
  int i;

  for (i = 0; i < 16; ++i) printf("%02x", digest[i]);
  printf("  %s\n", filename);
}

static FILE *open_outfile(const char *name) {
  if (strcmp("-", name) == 0) {
    set_binary_mode(stdout);
    return stdout;
  } else {
    FILE *file = fopen(name, "wb");
    if (!file) fatal("Failed to open output file '%s'", name);
    return file;
  }
}

static int main_loop(int argc, const char **argv_) {
  aom_codec_ctx_t decoder;
  char *fn = NULL;
  int i;
  int ret = EXIT_FAILURE;
  uint8_t *buf = NULL;
  size_t bytes_in_buffer = 0, buffer_size = 0;
  FILE *infile;
  int frame_in = 0, frame_out = 0, flipuv = 0, noblit = 0;
  int do_md5 = 0, progress = 0;
  int stop_after = 0, summary = 0, quiet = 1;
  int arg_skip = 0;
  int keep_going = 0;
  uint64_t dx_time = 0;
  struct arg arg;
  char **argv, **argi, **argj;

  int single_file;
  int use_y4m = 1;
  int opt_yv12 = 0;
  int opt_i420 = 0;
  int opt_raw = 0;
  aom_codec_dec_cfg_t cfg = { 0, 0, 0 };
  unsigned int fixed_output_bit_depth = 0;
  unsigned int is_annexb = 0;
  int frames_corrupted = 0;
  int dec_flags = 0;
  int do_scale = 0;
  int operating_point = 0;
  int output_all_layers = 0;
  int skip_film_grain = 0;
  aom_image_t *scaled_img = NULL;
  aom_image_t *img_shifted = NULL;
  int frame_avail, got_data, flush_decoder = 0;
  int num_external_frame_buffers = 0;
  struct ExternalFrameBufferList ext_fb_list = { 0, NULL };

  const char *outfile_pattern = NULL;
  char outfile_name[PATH_MAX] = { 0 };
  FILE *outfile = NULL;

  FILE *framestats_file = NULL;

  MD5Context md5_ctx;
  unsigned char md5_digest[16];

  struct AvxDecInputContext input = { NULL, NULL, NULL };
  struct AvxInputContext aom_input_ctx;
  memset(&aom_input_ctx, 0, sizeof(aom_input_ctx));
#if CONFIG_WEBM_IO
  struct WebmInputContext webm_ctx;
  memset(&webm_ctx, 0, sizeof(webm_ctx));
  input.webm_ctx = &webm_ctx;
#endif
  struct ObuDecInputContext obu_ctx = { NULL, NULL, 0, 0, 0 };
  int is_ivf = 0;

  obu_ctx.avx_ctx = &aom_input_ctx;
  input.obu_ctx = &obu_ctx;
  input.aom_input_ctx = &aom_input_ctx;

  /* Parse command line */
  exec_name = argv_[0];
  argv = argv_dup(argc - 1, argv_ + 1);

  aom_codec_iface_t *interface = NULL;
  for (argi = argj = argv; (*argj = *argi); argi += arg.argv_step) {
    memset(&arg, 0, sizeof(arg));
    arg.argv_step = 1;

    if (arg_match(&arg, &help, argi)) {
      show_help(stdout, 0);
      exit(EXIT_SUCCESS);
    } else if (arg_match(&arg, &codecarg, argi)) {
      interface = get_aom_decoder_by_short_name(arg.val);
      if (!interface)
        die("Error: Unrecognized argument (%s) to --codec\n", arg.val);
    } else if (arg_match(&arg, &looparg, argi)) {
      // no-op
    } else if (arg_match(&arg, &outputfile, argi)) {
      outfile_pattern = arg.val;
    } else if (arg_match(&arg, &use_yv12, argi)) {
      use_y4m = 0;
      flipuv = 1;
      opt_yv12 = 1;
      opt_i420 = 0;
      opt_raw = 0;
    } else if (arg_match(&arg, &use_i420, argi)) {
      use_y4m = 0;
      flipuv = 0;
      opt_yv12 = 0;
      opt_i420 = 1;
      opt_raw = 0;
    } else if (arg_match(&arg, &rawvideo, argi)) {
      use_y4m = 0;
      opt_yv12 = 0;
      opt_i420 = 0;
      opt_raw = 1;
    } else if (arg_match(&arg, &flipuvarg, argi)) {
      flipuv = 1;
    } else if (arg_match(&arg, &noblitarg, argi)) {
      noblit = 1;
    } else if (arg_match(&arg, &progressarg, argi)) {
      progress = 1;
    } else if (arg_match(&arg, &limitarg, argi)) {
      stop_after = arg_parse_uint(&arg);
    } else if (arg_match(&arg, &skiparg, argi)) {
      arg_skip = arg_parse_uint(&arg);
    } else if (arg_match(&arg, &md5arg, argi)) {
      do_md5 = 1;
    } else if (arg_match(&arg, &framestatsarg, argi)) {
      framestats_file = fopen(arg.val, "w");
      if (!framestats_file) {
        die("Error: Could not open --framestats file (%s) for writing.\n",
            arg.val);
      }
    } else if (arg_match(&arg, &summaryarg, argi)) {
      summary = 1;
    } else if (arg_match(&arg, &threadsarg, argi)) {
      cfg.threads = arg_parse_uint(&arg);
#if !CONFIG_MULTITHREAD
      if (cfg.threads > 1) {
        die("Error: --threads=%d is not supported when CONFIG_MULTITHREAD = "
            "0.\n",
            cfg.threads);
      }
#endif
    } else if (arg_match(&arg, &verbosearg, argi)) {
      quiet = 0;
    } else if (arg_match(&arg, &scalearg, argi)) {
      do_scale = 1;
    } else if (arg_match(&arg, &fb_arg, argi)) {
      num_external_frame_buffers = arg_parse_uint(&arg);
    } else if (arg_match(&arg, &continuearg, argi)) {
      keep_going = 1;
    } else if (arg_match(&arg, &outbitdeptharg, argi)) {
      fixed_output_bit_depth = arg_parse_uint(&arg);
    } else if (arg_match(&arg, &isannexb, argi)) {
      is_annexb = 1;
      input.obu_ctx->is_annexb = 1;
    } else if (arg_match(&arg, &oppointarg, argi)) {
      operating_point = arg_parse_int(&arg);
    } else if (arg_match(&arg, &outallarg, argi)) {
      output_all_layers = 1;
    } else if (arg_match(&arg, &skipfilmgrain, argi)) {
      skip_film_grain = 1;
    } else {
      argj++;
    }
  }

  /* Check for unrecognized options */
  for (argi = argv; *argi; argi++)
    if (argi[0][0] == '-' && strlen(argi[0]) > 1)
      die("Error: Unrecognized option %s\n", *argi);

  /* Handle non-option arguments */
  fn = argv[0];

  if (!fn) {
    free(argv);
    fprintf(stderr, "No input file specified!\n");
    usage_exit();
  }
  /* Open file */
  infile = strcmp(fn, "-") ? fopen(fn, "rb") : set_binary_mode(stdin);

  if (!infile) {
    fatal("Failed to open input file '%s'", strcmp(fn, "-") ? fn : "stdin");
  }
#if CONFIG_OS_SUPPORT
  /* Make sure we don't dump to the terminal, unless forced to with -o - */
  if (!outfile_pattern && isatty(STDOUT_FILENO) && !do_md5 && !noblit) {
    fprintf(stderr,
            "Not dumping raw video to your terminal. Use '-o -' to "
            "override.\n");
    return EXIT_FAILURE;
  }
#endif
  input.aom_input_ctx->filename = fn;
  input.aom_input_ctx->file = infile;
  if (file_is_ivf(input.aom_input_ctx)) {
    input.aom_input_ctx->file_type = FILE_TYPE_IVF;
    is_ivf = 1;
  }
#if CONFIG_WEBM_IO
  else if (file_is_webm(input.webm_ctx, input.aom_input_ctx))
    input.aom_input_ctx->file_type = FILE_TYPE_WEBM;
#endif
  else if (file_is_obu(&obu_ctx))
    input.aom_input_ctx->file_type = FILE_TYPE_OBU;
  else if (file_is_raw(input.aom_input_ctx))
    input.aom_input_ctx->file_type = FILE_TYPE_RAW;
  else {
    fprintf(stderr, "Unrecognized input file type.\n");
#if !CONFIG_WEBM_IO
    fprintf(stderr, "aomdec was built without WebM container support.\n");
#endif
    free(argv);
    return EXIT_FAILURE;
  }

  outfile_pattern = outfile_pattern ? outfile_pattern : "-";
  single_file = is_single_file(outfile_pattern);

  if (!noblit && single_file) {
    generate_filename(outfile_pattern, outfile_name, PATH_MAX,
                      aom_input_ctx.width, aom_input_ctx.height, 0);
    if (do_md5)
      MD5Init(&md5_ctx);
    else
      outfile = open_outfile(outfile_name);
  }

  if (use_y4m && !noblit) {
    if (!single_file) {
      fprintf(stderr,
              "YUV4MPEG2 not supported with output patterns,"
              " try --i420 or --yv12 or --rawvideo.\n");
      return EXIT_FAILURE;
    }

#if CONFIG_WEBM_IO
    if (aom_input_ctx.file_type == FILE_TYPE_WEBM) {
      if (webm_guess_framerate(input.webm_ctx, input.aom_input_ctx)) {
        fprintf(stderr,
                "Failed to guess framerate -- error parsing "
                "webm file?\n");
        return EXIT_FAILURE;
      }
    }
#endif
  }

  aom_codec_iface_t *fourcc_interface =
      get_aom_decoder_by_fourcc(aom_input_ctx.fourcc);

  if (is_ivf && !fourcc_interface)
    fatal("Unsupported fourcc: %x\n", aom_input_ctx.fourcc);

  if (interface && fourcc_interface && interface != fourcc_interface)
    warn("Header indicates codec: %s\n",
         aom_codec_iface_name(fourcc_interface));
  else
    interface = fourcc_interface;

  if (!interface) interface = get_aom_decoder_by_index(0);

  dec_flags = 0;
  if (aom_codec_dec_init(&decoder, interface, &cfg, dec_flags)) {
    fprintf(stderr, "Failed to initialize decoder: %s\n",
            aom_codec_error(&decoder));
    goto fail2;
  }

  if (!quiet) fprintf(stderr, "%s\n", decoder.name);

  if (AOM_CODEC_CONTROL_TYPECHECKED(&decoder, AV1D_SET_IS_ANNEXB, is_annexb)) {
    fprintf(stderr, "Failed to set is_annexb: %s\n", aom_codec_error(&decoder));
    goto fail;
  }

  if (AOM_CODEC_CONTROL_TYPECHECKED(&decoder, AV1D_SET_OPERATING_POINT,
                                    operating_point)) {
    fprintf(stderr, "Failed to set operating_point: %s\n",
            aom_codec_error(&decoder));
    goto fail;
  }

  if (AOM_CODEC_CONTROL_TYPECHECKED(&decoder, AV1D_SET_OUTPUT_ALL_LAYERS,
                                    output_all_layers)) {
    fprintf(stderr, "Failed to set output_all_layers: %s\n",
            aom_codec_error(&decoder));
    goto fail;
  }

  if (AOM_CODEC_CONTROL_TYPECHECKED(&decoder, AV1D_SET_SKIP_FILM_GRAIN,
                                    skip_film_grain)) {
    fprintf(stderr, "Failed to set skip_film_grain: %s\n",
            aom_codec_error(&decoder));
    goto fail;
  }

  if (arg_skip) fprintf(stderr, "Skipping first %d frames.\n", arg_skip);
  while (arg_skip) {
    if (read_frame(&input, &buf, &bytes_in_buffer, &buffer_size)) break;
    arg_skip--;
  }

  if (num_external_frame_buffers > 0) {
    ext_fb_list.num_external_frame_buffers = num_external_frame_buffers;
    ext_fb_list.ext_fb = (struct ExternalFrameBuffer *)calloc(
        num_external_frame_buffers, sizeof(*ext_fb_list.ext_fb));
    if (aom_codec_set_frame_buffer_functions(&decoder, get_av1_frame_buffer,
                                             release_av1_frame_buffer,
                                             &ext_fb_list)) {
      fprintf(stderr, "Failed to configure external frame buffers: %s\n",
              aom_codec_error(&decoder));
      goto fail;
    }
  }

  frame_avail = 1;
  got_data = 0;

  if (framestats_file) fprintf(framestats_file, "bytes,qp\r\n");

  /* Decode file */
  while (frame_avail || got_data) {
    aom_codec_iter_t iter = NULL;
    aom_image_t *img;
    struct aom_usec_timer timer;
    int corrupted = 0;

    frame_avail = 0;
    if (!stop_after || frame_in < stop_after) {
      if (!read_frame(&input, &buf, &bytes_in_buffer, &buffer_size)) {
        frame_avail = 1;
        frame_in++;

        aom_usec_timer_start(&timer);

        if (aom_codec_decode(&decoder, buf, bytes_in_buffer, NULL)) {
          const char *detail = aom_codec_error_detail(&decoder);
          warn("Failed to decode frame %d: %s", frame_in,
               aom_codec_error(&decoder));

          if (detail) warn("Additional information: %s", detail);
          if (!keep_going) goto fail;
        }

        if (framestats_file) {
          int qp;
          if (AOM_CODEC_CONTROL_TYPECHECKED(&decoder, AOMD_GET_LAST_QUANTIZER,
                                            &qp)) {
            warn("Failed AOMD_GET_LAST_QUANTIZER: %s",
                 aom_codec_error(&decoder));
            if (!keep_going) goto fail;
          }
          fprintf(framestats_file, "%d,%d\r\n", (int)bytes_in_buffer, qp);
        }

        aom_usec_timer_mark(&timer);
        dx_time += aom_usec_timer_elapsed(&timer);
      } else {
        flush_decoder = 1;
      }
    } else {
      flush_decoder = 1;
    }

    aom_usec_timer_start(&timer);

    if (flush_decoder) {
      // Flush the decoder.
      if (aom_codec_decode(&decoder, NULL, 0, NULL)) {
        warn("Failed to flush decoder: %s", aom_codec_error(&decoder));
      }
    }

    aom_usec_timer_mark(&timer);
    dx_time += aom_usec_timer_elapsed(&timer);

    got_data = 0;
    while ((img = aom_codec_get_frame(&decoder, &iter))) {
      ++frame_out;
      got_data = 1;

      if (AOM_CODEC_CONTROL_TYPECHECKED(&decoder, AOMD_GET_FRAME_CORRUPTED,
                                        &corrupted)) {
        warn("Failed AOM_GET_FRAME_CORRUPTED: %s", aom_codec_error(&decoder));
        if (!keep_going) goto fail;
      }
      frames_corrupted += corrupted;

      if (progress) show_progress(frame_in, frame_out, dx_time);

      if (!noblit) {
        const int PLANES_YUV[] = { AOM_PLANE_Y, AOM_PLANE_U, AOM_PLANE_V };
        const int PLANES_YVU[] = { AOM_PLANE_Y, AOM_PLANE_V, AOM_PLANE_U };
        const int *planes = flipuv ? PLANES_YVU : PLANES_YUV;

        if (do_scale) {
          if (frame_out == 1) {
            // If the output frames are to be scaled to a fixed display size
            // then use the width and height specified in the container. If
            // either of these is set to 0, use the display size set in the
            // first frame header. If that is unavailable, use the raw decoded
            // size of the first decoded frame.
            int render_width = aom_input_ctx.width;
            int render_height = aom_input_ctx.height;
            if (!render_width || !render_height) {
              int render_size[2];
              if (AOM_CODEC_CONTROL_TYPECHECKED(&decoder, AV1D_GET_DISPLAY_SIZE,
                                                render_size)) {
                // As last resort use size of first frame as display size.
                render_width = img->d_w;
                render_height = img->d_h;
              } else {
                render_width = render_size[0];
                render_height = render_size[1];
              }
            }
            scaled_img =
                aom_img_alloc(NULL, img->fmt, render_width, render_height, 16);
            scaled_img->bit_depth = img->bit_depth;
            scaled_img->monochrome = img->monochrome;
            scaled_img->csp = img->csp;
          }

          if (img->d_w != scaled_img->d_w || img->d_h != scaled_img->d_h) {
#if CONFIG_LIBYUV
            libyuv_scale(img, scaled_img, kFilterBox);
            img = scaled_img;
#else
            fprintf(
                stderr,
                "Failed to scale output frame: %s.\n"
                "libyuv is required for scaling but is currently disabled.\n"
                "Be sure to specify -DCONFIG_LIBYUV=1 when running cmake.\n",
                aom_codec_error(&decoder));
            goto fail;
#endif
          }
        }
        // Default to codec bit depth if output bit depth not set
        unsigned int output_bit_depth;
        if (!fixed_output_bit_depth && single_file) {
          output_bit_depth = img->bit_depth;
        } else {
          output_bit_depth = fixed_output_bit_depth;
        }
        // Shift up or down if necessary
        if (output_bit_depth != 0)
          aom_shift_img(output_bit_depth, &img, &img_shifted);

        aom_input_ctx.width = img->d_w;
        aom_input_ctx.height = img->d_h;

        int num_planes = (opt_raw && img->monochrome) ? 1 : 3;
        if (single_file) {
          if (use_y4m) {
            char y4m_buf[Y4M_BUFFER_SIZE] = { 0 };
            size_t len = 0;
            if (frame_out == 1) {
              // Y4M file header
              len = y4m_write_file_header(
                  y4m_buf, sizeof(y4m_buf), aom_input_ctx.width,
                  aom_input_ctx.height, &aom_input_ctx.framerate,
                  img->monochrome, img->csp, img->fmt, img->bit_depth);
              if (img->csp == AOM_CSP_COLOCATED) {
                fprintf(stderr,
                        "Warning: Y4M lacks a colorspace for colocated "
                        "chroma. Using a placeholder.\n");
              }
              if (do_md5) {
                MD5Update(&md5_ctx, (md5byte *)y4m_buf, (unsigned int)len);
              } else {
                fputs(y4m_buf, outfile);
              }
            }

            // Y4M frame header
            len = y4m_write_frame_header(y4m_buf, sizeof(y4m_buf));
            if (do_md5) {
              MD5Update(&md5_ctx, (md5byte *)y4m_buf, (unsigned int)len);
              y4m_update_image_md5(img, planes, &md5_ctx);
            } else {
              fputs(y4m_buf, outfile);
              y4m_write_image_file(img, planes, outfile);
            }
          } else {
            if (frame_out == 1) {
              // Check if --yv12 or --i420 options are consistent with the
              // bit-stream decoded
              if (opt_i420) {
                if (img->fmt != AOM_IMG_FMT_I420 &&
                    img->fmt != AOM_IMG_FMT_I42016) {
                  fprintf(stderr,
                          "Cannot produce i420 output for bit-stream.\n");
                  goto fail;
                }
              }
              if (opt_yv12) {
                if ((img->fmt != AOM_IMG_FMT_I420 &&
                     img->fmt != AOM_IMG_FMT_YV12) ||
                    img->bit_depth != 8) {
                  fprintf(stderr,
                          "Cannot produce yv12 output for bit-stream.\n");
                  goto fail;
                }
              }
            }
            if (do_md5) {
              raw_update_image_md5(img, planes, num_planes, &md5_ctx);
            } else {
              raw_write_image_file(img, planes, num_planes, outfile);
            }
          }
        } else {
          generate_filename(outfile_pattern, outfile_name, PATH_MAX, img->d_w,
                            img->d_h, frame_in);
          if (do_md5) {
            MD5Init(&md5_ctx);
            if (use_y4m) {
              y4m_update_image_md5(img, planes, &md5_ctx);
            } else {
              raw_update_image_md5(img, planes, num_planes, &md5_ctx);
            }
            MD5Final(md5_digest, &md5_ctx);
            print_md5(md5_digest, outfile_name);
          } else {
            outfile = open_outfile(outfile_name);
            if (use_y4m) {
              y4m_write_image_file(img, planes, outfile);
            } else {
              raw_write_image_file(img, planes, num_planes, outfile);
            }
            fclose(outfile);
          }
        }
      }
    }
  }

  if (summary || progress) {
    show_progress(frame_in, frame_out, dx_time);
    fprintf(stderr, "\n");
  }

  if (frames_corrupted) {
    fprintf(stderr, "WARNING: %d frames corrupted.\n", frames_corrupted);
  } else {
    ret = EXIT_SUCCESS;
  }

fail:

  if (aom_codec_destroy(&decoder)) {
    fprintf(stderr, "Failed to destroy decoder: %s\n",
            aom_codec_error(&decoder));
  }

fail2:

  if (!noblit && single_file) {
    if (do_md5) {
      MD5Final(md5_digest, &md5_ctx);
      print_md5(md5_digest, outfile_name);
    } else {
      fclose(outfile);
    }
  }

#if CONFIG_WEBM_IO
  if (input.aom_input_ctx->file_type == FILE_TYPE_WEBM)
    webm_free(input.webm_ctx);
#endif
  if (input.aom_input_ctx->file_type == FILE_TYPE_OBU)
    obudec_free(input.obu_ctx);

  if (input.aom_input_ctx->file_type != FILE_TYPE_WEBM) free(buf);

  if (scaled_img) aom_img_free(scaled_img);
  if (img_shifted) aom_img_free(img_shifted);

  for (i = 0; i < ext_fb_list.num_external_frame_buffers; ++i) {
    free(ext_fb_list.ext_fb[i].data);
  }
  free(ext_fb_list.ext_fb);

  fclose(infile);
  if (framestats_file) fclose(framestats_file);

  free(argv);

  return ret;
}

int main(int argc, const char **argv_) {
  unsigned int loops = 1, i;
  char **argv, **argi, **argj;
  struct arg arg;
  int error = 0;

  argv = argv_dup(argc - 1, argv_ + 1);
  for (argi = argj = argv; (*argj = *argi); argi += arg.argv_step) {
    memset(&arg, 0, sizeof(arg));
    arg.argv_step = 1;

    if (arg_match(&arg, &looparg, argi)) {
      loops = arg_parse_uint(&arg);
      break;
    }
  }
  free(argv);
  for (i = 0; !error && i < loops; i++) error = main_loop(argc, argv_);
  return error;
}