1 /*
2 * G.726 raw demuxer
3 * Copyright 2017 Carl Eugen Hoyos
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg 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 * FFmpeg 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 FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #include "avformat.h"
23 #include "internal.h"
24 #include "libavutil/opt.h"
25
26 typedef struct G726Context {
27 AVClass *class;
28 int code_size;
29 int sample_rate;
30 } G726Context;
31
g726_read_header(AVFormatContext * s)32 static int g726_read_header(AVFormatContext *s)
33 {
34 G726Context *c = s->priv_data;
35 AVStream *st = avformat_new_stream(s, NULL);
36 if (!st)
37 return AVERROR(ENOMEM);
38
39 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
40 st->codecpar->codec_id = s->iformat->raw_codec_id;
41
42 st->codecpar->sample_rate = c->sample_rate;
43 st->codecpar->bits_per_coded_sample = c->code_size;
44 st->codecpar->bit_rate = ((int[]){ 16000, 24000, 32000, 40000 })[c->code_size - 2];
45 st->codecpar->channels = 1;
46
47 return 0;
48 }
49
g726_read_packet(AVFormatContext * s,AVPacket * pkt)50 static int g726_read_packet(AVFormatContext *s, AVPacket *pkt)
51 {
52 int res;
53 res = av_get_packet(s->pb, pkt, 1020); // a size similar to RAW_PACKET_SIZE divisible by all code_size values
54 if (res < 0)
55 return res;
56 return 0;
57 }
58
59 #define OFFSET(x) offsetof(G726Context, x)
60 static const AVOption options[] = {
61 { "code_size", "Bits per G.726 code",
62 OFFSET(code_size), AV_OPT_TYPE_INT, {.i64 = 4}, 2, 5, AV_OPT_FLAG_DECODING_PARAM },
63 { "sample_rate", "",
64 OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64 = 8000}, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
65 { NULL },
66 };
67
68 #if CONFIG_G726_DEMUXER
69 static const AVClass g726le_demuxer_class = {
70 .class_name = "G.726 big-endian demuxer",
71 .item_name = av_default_item_name,
72 .option = options,
73 .version = LIBAVUTIL_VERSION_INT,
74 };
75
76 AVInputFormat ff_g726_demuxer = {
77 .name = "g726",
78 .long_name = NULL_IF_CONFIG_SMALL("raw big-endian G.726 (\"left aligned\")"),
79 .read_header = g726_read_header,
80 .read_packet = g726_read_packet,
81 .priv_data_size = sizeof(G726Context),
82 .priv_class = &g726le_demuxer_class,
83 .raw_codec_id = AV_CODEC_ID_ADPCM_G726,
84 };
85 #endif
86
87 #if CONFIG_G726LE_DEMUXER
88 static const AVClass g726_demuxer_class = {
89 .class_name = "G.726 little-endian demuxer",
90 .item_name = av_default_item_name,
91 .option = options,
92 .version = LIBAVUTIL_VERSION_INT,
93 };
94
95 AVInputFormat ff_g726le_demuxer = {
96 .name = "g726le",
97 .long_name = NULL_IF_CONFIG_SMALL("raw little-endian G.726 (\"right aligned\")"),
98 .read_header = g726_read_header,
99 .read_packet = g726_read_packet,
100 .priv_data_size = sizeof(G726Context),
101 .priv_class = &g726_demuxer_class,
102 .raw_codec_id = AV_CODEC_ID_ADPCM_G726LE,
103 };
104 #endif
105
106