ref: b60617f5ff9e50ac0d7878752efba27bcaaf3037
dir: /ivfdec.c/
/* * 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 "vpx_ports/mem_ops.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 (*den > 0 && *den < 1000000000 && *num > 0 && *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, 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; }