1 /*
2 * copyright (c) 2008 Paul Kendall <paul@kcbbs.gen.nz>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 /**
22 * @file
23 * AAC LATM parser
24 */
25
26 #include <stdint.h>
28
29 #define LATM_HEADER 0x56e000 // 0x2b7 (11 bits)
30 #define LATM_MASK 0xFFE000 // top 11 bits
31 #define LATM_SIZE_MASK 0x001FFF // bottom 13 bits
32
37
38 /**
39 * Find the end of the current frame in the bitstream.
40 * @return the position of the first byte of the next frame, or -1
41 */
43 int buf_size)
44 {
47 int pic_found, i;
49
52
53 if (!pic_found) {
54 for (i = 0; i < buf_size; i++) {
55 state = (state<<8) | buf[i];
57 i++;
59 pic_found = 1;
60 break;
61 }
62 }
63 }
64
65 if (pic_found) {
66 /* EOF considered as end of frame */
67 if (buf_size == 0)
68 return 0;
72 return (state & LATM_SIZE_MASK) - s->
count;
73 }
74 }
75
79
81 }
82
84 const uint8_t **poutbuf,
int *poutbuf_size,
86 {
89 int next;
90
92 next = buf_size;
93 } else {
95
98 *poutbuf_size = 0;
99 return buf_size;
100 }
101 }
103 *poutbuf_size = buf_size;
104 return next;
105 }
106
112 };
static int latm_find_frame_end(AVCodecParserContext *s1, const uint8_t *buf, int buf_size)
Find the end of the current frame in the bitstream.
int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
Combine the (truncated) bitstream to a complete frame.
void ff_parse_close(AVCodecParserContext *s)
static int latm_parse(AVCodecParserContext *s1, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size)
main external API structure.
uint32_t state
contains the last few bytes in MSB order
AVCodecParser ff_aac_latm_parser
#define PARSER_FLAG_COMPLETE_FRAMES