115 строки
3.3 KiB
C
115 строки
3.3 KiB
C
/*
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* Copyright (c) 2013 The WebM project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "./ivfdec.h"
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#include <stdio.h>
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#include <stdlib.h>
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int file_is_ivf(struct VpxInputContext *input_ctx) {
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char raw_hdr[32];
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int is_ivf = 0;
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if (fread(raw_hdr, 1, 32, input_ctx->file) == 32) {
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if (raw_hdr[0] == 'D' && raw_hdr[1] == 'K' &&
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raw_hdr[2] == 'I' && raw_hdr[3] == 'F') {
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is_ivf = 1;
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if (mem_get_le16(raw_hdr + 4) != 0) {
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fprintf(stderr, "Error: Unrecognized IVF version! This file may not"
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" decode properly.");
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}
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input_ctx->fourcc = mem_get_le32(raw_hdr + 8);
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input_ctx->width = mem_get_le16(raw_hdr + 12);
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input_ctx->height = mem_get_le16(raw_hdr + 14);
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input_ctx->framerate.numerator = mem_get_le32(raw_hdr + 16);
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input_ctx->framerate.denominator = mem_get_le32(raw_hdr + 20);
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/* Some versions of vpxenc used 1/(2*fps) for the timebase, so
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* we can guess the framerate using only the timebase in this
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* case. Other files would require reading ahead to guess the
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* timebase, like we do for webm.
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*/
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if (input_ctx->framerate.numerator < 1000) {
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/* Correct for the factor of 2 applied to the timebase in the
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* encoder.
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*/
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if (input_ctx->framerate.numerator & 1)
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input_ctx->framerate.denominator <<= 1;
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else
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input_ctx->framerate.numerator >>= 1;
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} else {
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/* Don't know FPS for sure, and don't have readahead code
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* (yet?), so just default to 30fps.
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*/
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input_ctx->framerate.numerator = 30;
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input_ctx->framerate.denominator = 1;
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}
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}
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}
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if (!is_ivf) {
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rewind(input_ctx->file);
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input_ctx->detect.buf_read = 0;
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} else {
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input_ctx->detect.position = 4;
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}
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return is_ivf;
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}
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int ivf_read_frame(struct VpxInputContext *input_ctx,
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uint8_t **buffer,
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size_t *bytes_read,
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size_t *buffer_size) {
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char raw_header[IVF_FRAME_HDR_SZ] = {0};
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size_t frame_size = 0;
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FILE *infile = input_ctx->file;
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if (input_ctx->file_type != FILE_TYPE_IVF)
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return 0;
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if (fread(raw_header, IVF_FRAME_HDR_SZ, 1, infile) != 1) {
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if (!feof(infile))
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warn("Failed to read frame size\n");
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} else {
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frame_size = mem_get_le32(raw_header);
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if (frame_size > 256 * 1024 * 1024) {
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warn("Read invalid frame size (%u)\n", (unsigned int)frame_size);
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frame_size = 0;
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}
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if (frame_size > *buffer_size) {
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uint8_t *new_buffer = realloc(*buffer, 2 * frame_size);
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if (new_buffer) {
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*buffer = new_buffer;
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*buffer_size = 2 * frame_size;
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} else {
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warn("Failed to allocate compressed data buffer\n");
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frame_size = 0;
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}
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}
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}
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if (!feof(infile)) {
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if (fread(*buffer, 1, frame_size, infile) != frame_size) {
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warn("Failed to read full frame\n");
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return 1;
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}
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*bytes_read = frame_size;
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return 0;
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}
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return 1;
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}
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