1 /*
2 * Copyright (c) 2015 Ganesh Ajjanagadde
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 * G.729 audio parser
24 *
25 * Splits packets into individual blocks.
26 */
27
28 #include "libavutil/avassert.h"
29 #include "parser.h"
30 #include "g729.h"
31
32 typedef struct G729ParseContext {
33 ParseContext pc;
34 int block_size;
35 int duration;
36 int remaining;
37 } G729ParseContext;
38
g729_parse(AVCodecParserContext * s1,AVCodecContext * avctx,const uint8_t ** poutbuf,int * poutbuf_size,const uint8_t * buf,int buf_size)39 static int g729_parse(AVCodecParserContext *s1, AVCodecContext *avctx,
40 const uint8_t **poutbuf, int *poutbuf_size,
41 const uint8_t *buf, int buf_size)
42 {
43 G729ParseContext *s = s1->priv_data;
44 ParseContext *pc = &s->pc;
45 int next;
46
47 if (!s->block_size) {
48 /* FIXME: replace this heuristic block_size with more precise estimate */
49 s->block_size = (avctx->bit_rate < 8000) ? G729D_6K4_BLOCK_SIZE : G729_8K_BLOCK_SIZE;
50 if (avctx->codec_id == AV_CODEC_ID_ACELP_KELVIN)
51 s->block_size++;
52 // channels > 2 is invalid, we pass the packet on unchanged
53 if (avctx->channels > 2)
54 s->block_size = 0;
55 s->block_size *= avctx->channels;
56 s->duration = avctx->frame_size;
57 }
58
59 if (!s->block_size) {
60 *poutbuf = buf;
61 *poutbuf_size = buf_size;
62 return buf_size;
63 }
64
65 if (!s->remaining)
66 s->remaining = s->block_size;
67 if (s->remaining <= buf_size) {
68 next = s->remaining;
69 s->remaining = 0;
70 } else {
71 next = END_NOT_FOUND;
72 s->remaining -= buf_size;
73 }
74
75 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0 || !buf_size) {
76 *poutbuf = NULL;
77 *poutbuf_size = 0;
78 return buf_size;
79 }
80
81 s1->duration = s->duration;
82
83 *poutbuf = buf;
84 *poutbuf_size = buf_size;
85 return next;
86 }
87
88 AVCodecParser ff_g729_parser = {
89 .codec_ids = { AV_CODEC_ID_G729, AV_CODEC_ID_ACELP_KELVIN },
90 .priv_data_size = sizeof(G729ParseContext),
91 .parser_parse = g729_parse,
92 .parser_close = ff_parse_close,
93 };
94