1 /*
2 * Copyright (c) 2014 Stefano Sabatini
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a copy
5 * of this software and associated documentation files (the "Software"), to deal
6 * in the Software without restriction, including without limitation the rights
7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8 * copies of the Software, and to permit persons to whom the Software is
9 * furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
20 * THE SOFTWARE.
21 */
22
23 /**
24 * @file
25 * libavformat AVIOContext API example.
26 *
27 * Make libavformat demuxer access media content through a custom
28 * AVIOContext read callback.
29 * @example avio_reading.c
30 */
31
32 #include <libavcodec/avcodec.h>
33 #include <libavformat/avformat.h>
34 #include <libavformat/avio.h>
35 #include <libavutil/file.h>
36
37 struct buffer_data {
38 uint8_t *ptr;
39 size_t size; ///< size left in the buffer
40 };
41
read_packet(void * opaque,uint8_t * buf,int buf_size)42 static int read_packet(void *opaque, uint8_t *buf, int buf_size)
43 {
44 struct buffer_data *bd = (struct buffer_data *)opaque;
45 buf_size = FFMIN(buf_size, bd->size);
46
47 if (!buf_size)
48 return AVERROR_EOF;
49 printf("ptr:%p size:%zu\n", bd->ptr, bd->size);
50
51 /* copy internal buffer data to buf */
52 memcpy(buf, bd->ptr, buf_size);
53 bd->ptr += buf_size;
54 bd->size -= buf_size;
55
56 return buf_size;
57 }
58
main(int argc,char * argv[])59 int main(int argc, char *argv[])
60 {
61 AVFormatContext *fmt_ctx = NULL;
62 AVIOContext *avio_ctx = NULL;
63 uint8_t *buffer = NULL, *avio_ctx_buffer = NULL;
64 size_t buffer_size, avio_ctx_buffer_size = 4096;
65 char *input_filename = NULL;
66 int ret = 0;
67 struct buffer_data bd = { 0 };
68
69 if (argc != 2) {
70 fprintf(stderr, "usage: %s input_file\n"
71 "API example program to show how to read from a custom buffer "
72 "accessed through AVIOContext.\n", argv[0]);
73 return 1;
74 }
75 input_filename = argv[1];
76
77 /* slurp file content into buffer */
78 ret = av_file_map(input_filename, &buffer, &buffer_size, 0, NULL);
79 if (ret < 0)
80 goto end;
81
82 /* fill opaque structure used by the AVIOContext read callback */
83 bd.ptr = buffer;
84 bd.size = buffer_size;
85
86 if (!(fmt_ctx = avformat_alloc_context())) {
87 ret = AVERROR(ENOMEM);
88 goto end;
89 }
90
91 avio_ctx_buffer = av_malloc(avio_ctx_buffer_size);
92 if (!avio_ctx_buffer) {
93 ret = AVERROR(ENOMEM);
94 goto end;
95 }
96 avio_ctx = avio_alloc_context(avio_ctx_buffer, avio_ctx_buffer_size,
97 0, &bd, &read_packet, NULL, NULL);
98 if (!avio_ctx) {
99 ret = AVERROR(ENOMEM);
100 goto end;
101 }
102 fmt_ctx->pb = avio_ctx;
103
104 ret = avformat_open_input(&fmt_ctx, NULL, NULL, NULL);
105 if (ret < 0) {
106 fprintf(stderr, "Could not open input\n");
107 goto end;
108 }
109
110 ret = avformat_find_stream_info(fmt_ctx, NULL);
111 if (ret < 0) {
112 fprintf(stderr, "Could not find stream information\n");
113 goto end;
114 }
115
116 av_dump_format(fmt_ctx, 0, input_filename, 0);
117
118 end:
119 avformat_close_input(&fmt_ctx);
120
121 /* note: the internal buffer could have changed, and be != avio_ctx_buffer */
122 if (avio_ctx)
123 av_freep(&avio_ctx->buffer);
124 avio_context_free(&avio_ctx);
125
126 av_file_unmap(buffer, buffer_size);
127
128 if (ret < 0) {
129 fprintf(stderr, "Error occurred: %s\n", av_err2str(ret));
130 return 1;
131 }
132
133 return 0;
134 }
135