au.c
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1 /*
2  * AU muxer and demuxer
3  * Copyright (c) 2001 Fabrice Bellard
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  * First version by Francois Revol revol@free.fr
24  *
25  * Reference documents:
26  * http://www.opengroup.org/public/pubs/external/auformat.html
27  * http://www.goice.co.jp/member/mo/formats/au.html
28  */
29 
30 #include "avformat.h"
31 #include "internal.h"
32 #include "avio_internal.h"
33 #include "pcm.h"
34 
35 /* The libavcodec codecs we support, and the IDs they have in the file */
36 static const AVCodecTag codec_au_tags[] = {
37  { AV_CODEC_ID_PCM_MULAW, 1 },
38  { AV_CODEC_ID_PCM_S8, 2 },
39  { AV_CODEC_ID_PCM_S16BE, 3 },
40  { AV_CODEC_ID_PCM_S24BE, 4 },
41  { AV_CODEC_ID_PCM_S32BE, 5 },
42  { AV_CODEC_ID_PCM_F32BE, 6 },
43  { AV_CODEC_ID_PCM_F64BE, 7 },
44  { AV_CODEC_ID_PCM_ALAW, 27 },
45  { AV_CODEC_ID_NONE, 0 },
46 };
47 
48 #if CONFIG_AU_DEMUXER
49 
50 static int au_probe(AVProbeData *p)
51 {
52  /* check file header */
53  if (p->buf[0] == '.' && p->buf[1] == 's' &&
54  p->buf[2] == 'n' && p->buf[3] == 'd')
55  return AVPROBE_SCORE_MAX;
56  else
57  return 0;
58 }
59 
60 /* au input */
61 static int au_read_header(AVFormatContext *s)
62 {
63  int size;
64  unsigned int tag;
65  AVIOContext *pb = s->pb;
66  unsigned int id, channels, rate;
67  enum AVCodecID codec;
68  AVStream *st;
69 
70  /* check ".snd" header */
71  tag = avio_rl32(pb);
72  if (tag != MKTAG('.', 's', 'n', 'd'))
73  return -1;
74  size = avio_rb32(pb); /* header size */
75  avio_rb32(pb); /* data size */
76 
77  id = avio_rb32(pb);
78  rate = avio_rb32(pb);
79  channels = avio_rb32(pb);
80 
81  codec = ff_codec_get_id(codec_au_tags, id);
82 
83  if (!av_get_bits_per_sample(codec)) {
84  av_log_ask_for_sample(s, "could not determine bits per sample\n");
85  return AVERROR_PATCHWELCOME;
86  }
87 
88  if (channels == 0 || channels > 64) {
89  av_log(s, AV_LOG_ERROR, "Invalid number of channels %d\n", channels);
90  return AVERROR_INVALIDDATA;
91  }
92 
93  if (size >= 24) {
94  /* skip unused data */
95  avio_skip(pb, size - 24);
96  }
97 
98  /* now we are ready: build format streams */
99  st = avformat_new_stream(s, NULL);
100  if (!st)
101  return -1;
103  st->codec->codec_tag = id;
104  st->codec->codec_id = codec;
105  st->codec->channels = channels;
106  st->codec->sample_rate = rate;
107  avpriv_set_pts_info(st, 64, 1, rate);
108  return 0;
109 }
110 
111 #define BLOCK_SIZE 1024
112 
113 static int au_read_packet(AVFormatContext *s,
114  AVPacket *pkt)
115 {
116  int ret;
117 
118  ret= av_get_packet(s->pb, pkt, BLOCK_SIZE *
119  s->streams[0]->codec->channels *
121  if (ret < 0)
122  return ret;
123  pkt->stream_index = 0;
124 
125  /* note: we need to modify the packet size here to handle the last
126  packet */
127  pkt->size = ret;
128  return 0;
129 }
130 
131 AVInputFormat ff_au_demuxer = {
132  .name = "au",
133  .long_name = NULL_IF_CONFIG_SMALL("Sun AU"),
134  .read_probe = au_probe,
135  .read_header = au_read_header,
136  .read_packet = au_read_packet,
137  .read_seek = ff_pcm_read_seek,
138  .codec_tag = (const AVCodecTag* const []){ codec_au_tags, 0 },
139 };
140 #endif /* CONFIG_AU_DEMUXER */
141 
142 #if CONFIG_AU_MUXER
143 
144 /* if we don't know the size in advance */
145 #define AU_UNKNOWN_SIZE ((uint32_t)(~0))
146 
147 /* AUDIO_FILE header */
148 static int put_au_header(AVIOContext *pb, AVCodecContext *enc)
149 {
150  if(!enc->codec_tag)
151  return -1;
152  ffio_wfourcc(pb, ".snd"); /* magic number */
153  avio_wb32(pb, 24); /* header size */
154  avio_wb32(pb, AU_UNKNOWN_SIZE); /* data size */
155  avio_wb32(pb, (uint32_t)enc->codec_tag); /* codec ID */
156  avio_wb32(pb, enc->sample_rate);
157  avio_wb32(pb, (uint32_t)enc->channels);
158  return 0;
159 }
160 
161 static int au_write_header(AVFormatContext *s)
162 {
163  AVIOContext *pb = s->pb;
164 
165  s->priv_data = NULL;
166 
167  /* format header */
168  if (put_au_header(pb, s->streams[0]->codec) < 0) {
169  return -1;
170  }
171 
172  avio_flush(pb);
173 
174  return 0;
175 }
176 
177 static int au_write_packet(AVFormatContext *s, AVPacket *pkt)
178 {
179  AVIOContext *pb = s->pb;
180  avio_write(pb, pkt->data, pkt->size);
181  return 0;
182 }
183 
184 static int au_write_trailer(AVFormatContext *s)
185 {
186  AVIOContext *pb = s->pb;
187  int64_t file_size;
188 
189  if (s->pb->seekable) {
190 
191  /* update file size */
192  file_size = avio_tell(pb);
193  avio_seek(pb, 8, SEEK_SET);
194  avio_wb32(pb, (uint32_t)(file_size - 24));
195  avio_seek(pb, file_size, SEEK_SET);
196 
197  avio_flush(pb);
198  }
199 
200  return 0;
201 }
202 
203 AVOutputFormat ff_au_muxer = {
204  .name = "au",
205  .long_name = NULL_IF_CONFIG_SMALL("Sun AU"),
206  .mime_type = "audio/basic",
207  .extensions = "au",
208  .audio_codec = AV_CODEC_ID_PCM_S16BE,
209  .video_codec = AV_CODEC_ID_NONE,
210  .write_header = au_write_header,
211  .write_packet = au_write_packet,
212  .write_trailer = au_write_trailer,
213  .codec_tag = (const AVCodecTag* const []){ codec_au_tags, 0 },
214 };
215 #endif /* CONFIG_AU_MUXER */