aom/ivfdec.c

115 строки
3.3 KiB
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 "./ivfdec.h"
#include <stdio.h>
#include <stdlib.h>
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 (raw_hdr[0] == 'D' && raw_hdr[1] == 'K' &&
raw_hdr[2] == 'I' && raw_hdr[3] == 'F') {
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);
/* 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 (input_ctx->framerate.numerator < 1000) {
/* Correct for the factor of 2 applied to the timebase in the
* encoder.
*/
if (input_ctx->framerate.numerator & 1)
input_ctx->framerate.denominator <<= 1;
else
input_ctx->framerate.numerator >>= 1;
} else {
/* Don't know FPS for sure, and don't have readahead code
* (yet?), so just default to 30fps.
*/
input_ctx->framerate.numerator = 30;
input_ctx->framerate.denominator = 1;
}
}
}
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(struct VpxInputContext *input_ctx,
uint8_t **buffer,
size_t *bytes_read,
size_t *buffer_size) {
char raw_header[IVF_FRAME_HDR_SZ] = {0};
size_t frame_size = 0;
FILE *infile = input_ctx->file;
if (input_ctx->file_type != FILE_TYPE_IVF)
return 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;
}