1/*
2 * Copyright (c) 2012  Justin Ruggles
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 * GSM audio parser
24 *
25 * Splits packets into individual blocks.
26 */
27
28#include "libavutil/avassert.h"
29#include "parser.h"
30#include "gsm.h"
31
32typedef struct GSMParseContext {
33    ParseContext pc;
34    int block_size;
35    int duration;
36    int remaining;
37} GSMParseContext;
38
39static int gsm_parse(AVCodecParserContext *s1, AVCodecContext *avctx,
40                     const uint8_t **poutbuf, int *poutbuf_size,
41                     const uint8_t *buf, int buf_size)
42{
43    GSMParseContext *s = s1->priv_data;
44    ParseContext *pc = &s->pc;
45    int next;
46
47    if (!s->block_size) {
48        switch (avctx->codec_id) {
49        case AV_CODEC_ID_GSM:
50            s->block_size = GSM_BLOCK_SIZE;
51            s->duration   = GSM_FRAME_SIZE;
52            break;
53        case AV_CODEC_ID_GSM_MS:
54            s->block_size = avctx->block_align ? avctx->block_align
55                                               : GSM_MS_BLOCK_SIZE;
56            s->duration   = GSM_FRAME_SIZE * 2;
57            break;
58        default:
59            av_assert0(0);
60        }
61    }
62
63    if (!s->remaining)
64        s->remaining = s->block_size;
65    if (s->remaining <= buf_size) {
66        next = s->remaining;
67        s->remaining = 0;
68    } else {
69        next = END_NOT_FOUND;
70        s->remaining -= buf_size;
71    }
72
73    if (ff_combine_frame(pc, next, &buf, &buf_size) < 0 || !buf_size) {
74        *poutbuf      = NULL;
75        *poutbuf_size = 0;
76        return buf_size;
77    }
78
79    s1->duration = s->duration;
80
81    *poutbuf      = buf;
82    *poutbuf_size = buf_size;
83    return next;
84}
85
86const AVCodecParser ff_gsm_parser = {
87    .codec_ids      = { AV_CODEC_ID_GSM, AV_CODEC_ID_GSM_MS },
88    .priv_data_size = sizeof(GSMParseContext),
89    .parser_parse   = gsm_parse,
90    .parser_close   = ff_parse_close,
91};
92