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