1 /*
2 * G.729 bit format muxer and demuxer
3 * Copyright (c) 2007-2008 Vladimir Voroshilov
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 #include "avformat.h"
22 #include "internal.h"
23 #include "libavcodec/get_bits.h"
24 #include "libavcodec/put_bits.h"
25
26 #define MAX_FRAME_SIZE 10
27
28 #define SYNC_WORD 0x6b21
29 #define BIT_0 0x7f
30 #define BIT_1 0x81
31
32 #if CONFIG_BIT_DEMUXER
probe(const AVProbeData * p)33 static int probe(const AVProbeData *p)
34 {
35 int i = 0, j, valid = 0;
36
37 while (2 * i + 3 < p->buf_size){
38 if (AV_RL16(&p->buf[2 * i++]) != SYNC_WORD)
39 return 0;
40 j = AV_RL16(&p->buf[2 * i++]);
41 if (j != 0 && j != 0x10 && j != 0x40 && j != 0x50 && j != 0x76)
42 return 0;
43 if (j)
44 valid++;
45 i += j;
46 }
47 if (valid > 10)
48 return AVPROBE_SCORE_MAX;
49 if (valid > 2)
50 return AVPROBE_SCORE_EXTENSION - 1;
51 return 0;
52 }
53
read_header(AVFormatContext * s)54 static int read_header(AVFormatContext *s)
55 {
56 AVStream* st;
57
58 st=avformat_new_stream(s, NULL);
59 if (!st)
60 return AVERROR(ENOMEM);
61
62 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
63 st->codecpar->codec_id=AV_CODEC_ID_G729;
64 st->codecpar->sample_rate=8000;
65 st->codecpar->block_align = 16;
66 st->codecpar->channels=1;
67
68 avpriv_set_pts_info(st, 64, 1, 100);
69 return 0;
70 }
71
read_packet(AVFormatContext * s,AVPacket * pkt)72 static int read_packet(AVFormatContext *s,
73 AVPacket *pkt)
74 {
75 AVIOContext *pb = s->pb;
76 PutBitContext pbo;
77 uint16_t buf[8 * MAX_FRAME_SIZE + 2];
78 int packet_size;
79 uint16_t* src=buf;
80 int i, j, ret;
81 int64_t pos= avio_tell(pb);
82
83 if(avio_feof(pb))
84 return AVERROR_EOF;
85
86 avio_rl16(pb); // sync word
87 packet_size = avio_rl16(pb) / 8;
88 if(packet_size > MAX_FRAME_SIZE)
89 return AVERROR_INVALIDDATA;
90
91 ret = avio_read(pb, (uint8_t*)buf, (8 * packet_size) * sizeof(uint16_t));
92 if(ret<0)
93 return ret;
94 if(ret != 8 * packet_size * sizeof(uint16_t))
95 return AVERROR(EIO);
96
97 if ((ret = av_new_packet(pkt, packet_size)) < 0)
98 return ret;
99
100 init_put_bits(&pbo, pkt->data, packet_size);
101 for(j=0; j < packet_size; j++)
102 for(i=0; i<8;i++)
103 put_bits(&pbo,1, AV_RL16(src++) == BIT_1 ? 1 : 0);
104
105 flush_put_bits(&pbo);
106
107 pkt->duration=1;
108 pkt->pos = pos;
109 return 0;
110 }
111
112 AVInputFormat ff_bit_demuxer = {
113 .name = "bit",
114 .long_name = NULL_IF_CONFIG_SMALL("G.729 BIT file format"),
115 .read_probe = probe,
116 .read_header = read_header,
117 .read_packet = read_packet,
118 .extensions = "bit",
119 };
120 #endif
121
122 #if CONFIG_BIT_MUXER
write_header(AVFormatContext * s)123 static int write_header(AVFormatContext *s)
124 {
125 AVCodecParameters *par = s->streams[0]->codecpar;
126
127 if ((par->codec_id != AV_CODEC_ID_G729) || par->channels != 1) {
128 av_log(s, AV_LOG_ERROR,
129 "only codec g729 with 1 channel is supported by this format\n");
130 return AVERROR(EINVAL);
131 }
132
133 par->bits_per_coded_sample = 16;
134 par->block_align = (par->bits_per_coded_sample * par->channels) >> 3;
135
136 return 0;
137 }
138
write_packet(AVFormatContext * s,AVPacket * pkt)139 static int write_packet(AVFormatContext *s, AVPacket *pkt)
140 {
141 AVIOContext *pb = s->pb;
142 GetBitContext gb;
143 int i;
144
145 if (pkt->size != 10)
146 return AVERROR(EINVAL);
147
148 avio_wl16(pb, SYNC_WORD);
149 avio_wl16(pb, 8 * pkt->size);
150
151 init_get_bits(&gb, pkt->data, 8 * pkt->size);
152 for (i = 0; i < 8 * pkt->size; i++)
153 avio_wl16(pb, get_bits1(&gb) ? BIT_1 : BIT_0);
154
155 return 0;
156 }
157
158 AVOutputFormat ff_bit_muxer = {
159 .name = "bit",
160 .long_name = NULL_IF_CONFIG_SMALL("G.729 BIT file format"),
161 .mime_type = "audio/bit",
162 .extensions = "bit",
163 .audio_codec = AV_CODEC_ID_G729,
164 .video_codec = AV_CODEC_ID_NONE,
165 .write_header = write_header,
166 .write_packet = write_packet,
167 };
168 #endif
169