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 "config_components.h"
23
24 #include "avformat.h"
25 #include "internal.h"
26 #include "libavutil/opt.h"
27
28 typedef struct G726Context {
29 AVClass *class;
30 int code_size;
31 int sample_rate;
32 } G726Context;
33
g726_read_header(AVFormatContext * s)34 static int g726_read_header(AVFormatContext *s)
35 {
36 G726Context *c = s->priv_data;
37 AVStream *st = avformat_new_stream(s, NULL);
38 if (!st)
39 return AVERROR(ENOMEM);
40
41 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
42 st->codecpar->codec_id = s->iformat->raw_codec_id;
43
44 st->codecpar->sample_rate = c->sample_rate;
45 st->codecpar->bits_per_coded_sample = c->code_size;
46 st->codecpar->bit_rate = ((int[]){ 16000, 24000, 32000, 40000 })[c->code_size - 2];
47 st->codecpar->ch_layout.nb_channels = 1;
48
49 return 0;
50 }
51
g726_read_packet(AVFormatContext * s,AVPacket * pkt)52 static int g726_read_packet(AVFormatContext *s, AVPacket *pkt)
53 {
54 int res;
55 res = av_get_packet(s->pb, pkt, 1020); // a size similar to RAW_PACKET_SIZE divisible by all code_size values
56 if (res < 0)
57 return res;
58 return 0;
59 }
60
61 #define OFFSET(x) offsetof(G726Context, x)
62 static const AVOption options[] = {
63 { "code_size", "Bits per G.726 code",
64 OFFSET(code_size), AV_OPT_TYPE_INT, {.i64 = 4}, 2, 5, AV_OPT_FLAG_DECODING_PARAM },
65 { "sample_rate", "",
66 OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64 = 8000}, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
67 { NULL },
68 };
69
70 static const AVClass g726_demuxer_class = {
71 .class_name = "G.726 demuxer",
72 .item_name = av_default_item_name,
73 .option = options,
74 .version = LIBAVUTIL_VERSION_INT,
75 };
76
77 #if CONFIG_G726_DEMUXER
78 const AVInputFormat ff_g726_demuxer = {
79 .name = "g726",
80 .long_name = NULL_IF_CONFIG_SMALL("raw big-endian G.726 (\"left aligned\")"),
81 .read_header = g726_read_header,
82 .read_packet = g726_read_packet,
83 .priv_data_size = sizeof(G726Context),
84 .priv_class = &g726_demuxer_class,
85 .raw_codec_id = AV_CODEC_ID_ADPCM_G726,
86 };
87 #endif
88
89 #if CONFIG_G726LE_DEMUXER
90 const AVInputFormat ff_g726le_demuxer = {
91 .name = "g726le",
92 .long_name = NULL_IF_CONFIG_SMALL("raw little-endian G.726 (\"right aligned\")"),
93 .read_header = g726_read_header,
94 .read_packet = g726_read_packet,
95 .priv_data_size = sizeof(G726Context),
96 .priv_class = &g726_demuxer_class,
97 .raw_codec_id = AV_CODEC_ID_ADPCM_G726LE,
98 };
99 #endif
100
101