1/*
2 * gsm 06.10 decoder
3 * Copyright (c) 2010 Reimar D��ffinger <Reimar.Doeffinger@gmx.de>
4 *
5 * This file is part of Libav.
6 *
7 * Libav is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * Libav is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * GSM decoder
25 */
26
27#include "avcodec.h"
28#include "get_bits.h"
29#include "msgsmdec.h"
30
31#include "gsmdec_template.c"
32
33static av_cold int gsm_init(AVCodecContext *avctx)
34{
35    GSMContext *s = avctx->priv_data;
36
37    avctx->channels = 1;
38    if (!avctx->sample_rate)
39        avctx->sample_rate = 8000;
40    avctx->sample_fmt = AV_SAMPLE_FMT_S16;
41
42    switch (avctx->codec_id) {
43    case CODEC_ID_GSM:
44        avctx->frame_size  = GSM_FRAME_SIZE;
45        avctx->block_align = GSM_BLOCK_SIZE;
46        break;
47    case CODEC_ID_GSM_MS:
48        avctx->frame_size  = 2 * GSM_FRAME_SIZE;
49        avctx->block_align = GSM_MS_BLOCK_SIZE;
50    }
51
52    avcodec_get_frame_defaults(&s->frame);
53    avctx->coded_frame = &s->frame;
54
55    return 0;
56}
57
58static int gsm_decode_frame(AVCodecContext *avctx, void *data,
59                            int *got_frame_ptr, AVPacket *avpkt)
60{
61    GSMContext *s = avctx->priv_data;
62    int res;
63    GetBitContext gb;
64    const uint8_t *buf = avpkt->data;
65    int buf_size = avpkt->size;
66    int16_t *samples;
67
68    if (buf_size < avctx->block_align) {
69        av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
70        return AVERROR_INVALIDDATA;
71    }
72
73    /* get output buffer */
74    s->frame.nb_samples = avctx->frame_size;
75    if ((res = avctx->get_buffer(avctx, &s->frame)) < 0) {
76        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
77        return res;
78    }
79    samples = (int16_t *)s->frame.data[0];
80
81    switch (avctx->codec_id) {
82    case CODEC_ID_GSM:
83        init_get_bits(&gb, buf, buf_size * 8);
84        if (get_bits(&gb, 4) != 0xd)
85            av_log(avctx, AV_LOG_WARNING, "Missing GSM magic!\n");
86        res = gsm_decode_block(avctx, samples, &gb);
87        if (res < 0)
88            return res;
89        break;
90    case CODEC_ID_GSM_MS:
91        res = ff_msgsm_decode_block(avctx, samples, buf);
92        if (res < 0)
93            return res;
94    }
95
96    *got_frame_ptr   = 1;
97    *(AVFrame *)data = s->frame;
98
99    return avctx->block_align;
100}
101
102static void gsm_flush(AVCodecContext *avctx)
103{
104    GSMContext *s = avctx->priv_data;
105    memset(s, 0, sizeof(*s));
106}
107
108AVCodec ff_gsm_decoder = {
109    .name           = "gsm",
110    .type           = AVMEDIA_TYPE_AUDIO,
111    .id             = CODEC_ID_GSM,
112    .priv_data_size = sizeof(GSMContext),
113    .init           = gsm_init,
114    .decode         = gsm_decode_frame,
115    .flush          = gsm_flush,
116    .capabilities   = CODEC_CAP_DR1,
117    .long_name = NULL_IF_CONFIG_SMALL("GSM"),
118};
119
120AVCodec ff_gsm_ms_decoder = {
121    .name           = "gsm_ms",
122    .type           = AVMEDIA_TYPE_AUDIO,
123    .id             = CODEC_ID_GSM_MS,
124    .priv_data_size = sizeof(GSMContext),
125    .init           = gsm_init,
126    .decode         = gsm_decode_frame,
127    .flush          = gsm_flush,
128    .capabilities   = CODEC_CAP_DR1,
129    .long_name = NULL_IF_CONFIG_SMALL("GSM Microsoft variant"),
130};
131