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
31typedef struct G729ParseContext {
32    ParseContext pc;
33    int block_size;
34    int duration;
35    int remaining;
36} G729ParseContext;
37
38static 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
87const 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