1 /*
2  *  Copyright (c) 2013 The WebM project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #include <stdio.h>
12 #include <stdlib.h>
13 #include <string.h>
14 
15 #include "vpx_ports/mem_ops.h"
16 
17 #include "./ivfdec.h"
18 
19 static const char *IVF_SIGNATURE = "DKIF";
20 
fix_framerate(int * num,int * den)21 static void fix_framerate(int *num, int *den) {
22   // Some versions of vpxenc used 1/(2*fps) for the timebase, so
23   // we can guess the framerate using only the timebase in this
24   // case. Other files would require reading ahead to guess the
25   // timebase, like we do for webm.
26   if (*num < 1000) {
27     // Correct for the factor of 2 applied to the timebase in the encoder.
28     if (*num & 1)
29       *den *= 2;
30     else
31       *num /= 2;
32   } else {
33     // Don't know FPS for sure, and don't have readahead code
34     // (yet?), so just default to 30fps.
35     *num = 30;
36     *den = 1;
37   }
38 }
39 
file_is_ivf(struct VpxInputContext * input_ctx)40 int file_is_ivf(struct VpxInputContext *input_ctx) {
41   char raw_hdr[32];
42   int is_ivf = 0;
43 
44   if (fread(raw_hdr, 1, 32, input_ctx->file) == 32) {
45     if (memcmp(IVF_SIGNATURE, raw_hdr, 4) == 0) {
46       is_ivf = 1;
47 
48       if (mem_get_le16(raw_hdr + 4) != 0) {
49         fprintf(stderr, "Error: Unrecognized IVF version! This file may not"
50                 " decode properly.");
51       }
52 
53       input_ctx->fourcc = mem_get_le32(raw_hdr + 8);
54       input_ctx->width = mem_get_le16(raw_hdr + 12);
55       input_ctx->height = mem_get_le16(raw_hdr + 14);
56       input_ctx->framerate.numerator = mem_get_le32(raw_hdr + 16);
57       input_ctx->framerate.denominator = mem_get_le32(raw_hdr + 20);
58       fix_framerate(&input_ctx->framerate.numerator,
59                     &input_ctx->framerate.denominator);
60     }
61   }
62 
63   if (!is_ivf) {
64     rewind(input_ctx->file);
65     input_ctx->detect.buf_read = 0;
66   } else {
67     input_ctx->detect.position = 4;
68   }
69   return is_ivf;
70 }
71 
ivf_read_frame(FILE * infile,uint8_t ** buffer,size_t * bytes_read,size_t * buffer_size)72 int ivf_read_frame(FILE *infile, uint8_t **buffer,
73                    size_t *bytes_read, size_t *buffer_size) {
74   char raw_header[IVF_FRAME_HDR_SZ] = {0};
75   size_t frame_size = 0;
76 
77   if (fread(raw_header, IVF_FRAME_HDR_SZ, 1, infile) != 1) {
78     if (!feof(infile))
79       warn("Failed to read frame size\n");
80   } else {
81     frame_size = mem_get_le32(raw_header);
82 
83     if (frame_size > 256 * 1024 * 1024) {
84       warn("Read invalid frame size (%u)\n", (unsigned int)frame_size);
85       frame_size = 0;
86     }
87 
88     if (frame_size > *buffer_size) {
89       uint8_t *new_buffer = realloc(*buffer, 2 * frame_size);
90 
91       if (new_buffer) {
92         *buffer = new_buffer;
93         *buffer_size = 2 * frame_size;
94       } else {
95         warn("Failed to allocate compressed data buffer\n");
96         frame_size = 0;
97       }
98     }
99   }
100 
101   if (!feof(infile)) {
102     if (fread(*buffer, 1, frame_size, infile) != frame_size) {
103       warn("Failed to read full frame\n");
104       return 1;
105     }
106 
107     *bytes_read = frame_size;
108     return 0;
109   }
110 
111   return 1;
112 }
113