ivfdec.c 4.46 KiB
/*
 *  Copyright (c) 2013 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.
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "./ivfdec.h"
static const char *IVF_SIGNATURE = "DKIF";
static void fix_framerate(int *num, int *den) {
  // Some versions of vpxenc used 1/(2*fps) for the timebase, so
  // we can guess the framerate using only the timebase in this
  // case. Other files would require reading ahead to guess the
  // timebase, like we do for webm.
  if (*num < 1000) {
    // Correct for the factor of 2 applied to the timebase in the encoder.
    if (*num & 1)
      *den *= 2;
    else
      *num /= 2;
  } else {
    // Don't know FPS for sure, and don't have readahead code
    // (yet?), so just default to 30fps.
    *num = 30;
    *den = 1;
int file_is_ivf(struct VpxInputContext *input_ctx) {
  char raw_hdr[32];
  int is_ivf = 0;
  if (fread(raw_hdr, 1, 32, input_ctx->file) == 32) {
    if (memcmp(IVF_SIGNATURE, raw_hdr, 4) == 0) {
      is_ivf = 1;
      if (mem_get_le16(raw_hdr + 4) != 0) {
        fprintf(stderr, "Error: Unrecognized IVF version! This file may not"
                " decode properly.");
      input_ctx->fourcc = mem_get_le32(raw_hdr + 8);
      input_ctx->width = mem_get_le16(raw_hdr + 12);
      input_ctx->height = mem_get_le16(raw_hdr + 14);
      input_ctx->framerate.numerator = mem_get_le32(raw_hdr + 16);
      input_ctx->framerate.denominator = mem_get_le32(raw_hdr + 20);
      fix_framerate(&input_ctx->framerate.numerator,
                    &input_ctx->framerate.denominator);
  if (!is_ivf) {
    rewind(input_ctx->file);
    input_ctx->detect.buf_read = 0;
  } else {
    input_ctx->detect.position = 4;
  return is_ivf;
int ivf_read_frame(FILE *infile, uint8_t **buffer,
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size_t *bytes_read, size_t *buffer_size) { char raw_header[IVF_FRAME_HDR_SZ] = {0}; size_t frame_size = 0; if (fread(raw_header, IVF_FRAME_HDR_SZ, 1, infile) != 1) { if (!feof(infile)) warn("Failed to read frame size\n"); } else { frame_size = mem_get_le32(raw_header); if (frame_size > 256 * 1024 * 1024) { warn("Read invalid frame size (%u)\n", (unsigned int)frame_size); frame_size = 0; } if (frame_size > *buffer_size) { uint8_t *new_buffer = realloc(*buffer, 2 * frame_size); if (new_buffer) { *buffer = new_buffer; *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; } return 1; } struct vpx_video { FILE *file; unsigned char *buffer; size_t buffer_size; size_t frame_size; unsigned int fourcc; int width; int height; }; vpx_video_t *vpx_video_open_file(FILE *file) { char raw_hdr[32]; vpx_video_t *video; if (fread(raw_hdr, 1, 32, file) != 32) return NULL; // Can't read file header; if (memcmp(IVF_SIGNATURE, raw_hdr, 4) != 0) return NULL; // Wrong IVF signature if (mem_get_le16(raw_hdr + 4) != 0) return NULL; // Wrong IVF version video = (vpx_video_t *)malloc(sizeof(*video)); video->file = file; video->buffer = NULL; video->buffer_size = 0; video->frame_size = 0; video->fourcc = mem_get_le32(raw_hdr + 8);
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video->width = mem_get_le16(raw_hdr + 12); video->height = mem_get_le16(raw_hdr + 14); return video; } void vpx_video_close(vpx_video_t *video) { if (video) { free(video->buffer); free(video); } } int vpx_video_get_width(vpx_video_t *video) { return video->width; } int vpx_video_get_height(vpx_video_t *video) { return video->height; } unsigned int vpx_video_get_fourcc(vpx_video_t *video) { return video->fourcc; } int vpx_video_read_frame(vpx_video_t *video) { return !ivf_read_frame(video->file, &video->buffer, &video->frame_size, &video->buffer_size); } const unsigned char *vpx_video_get_frame(vpx_video_t *video, size_t *size) { if (size) *size = video->frame_size; return video->buffer; }