* some minor modification by Philip Gladston
[libav.git] / libav / audio.c
1 /*
2 * Linux audio play and grab interface
3 * Copyright (c) 2000, 2001 Gerard Lantau.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 */
19 #include "avformat.h"
20
21 #include <stdlib.h>
22 #include <stdio.h>
23 #include <string.h>
24 #include <linux/soundcard.h>
25 #include <unistd.h>
26 #include <fcntl.h>
27 #include <sys/ioctl.h>
28 #include <sys/mman.h>
29 #include <sys/time.h>
30
31 const char *audio_device = "/dev/dsp";
32
33 #define AUDIO_BLOCK_SIZE 4096
34
35 typedef struct {
36 int fd;
37 int sample_rate;
38 int channels;
39 int frame_size; /* in bytes ! */
40 int codec_id;
41 UINT8 buffer[AUDIO_BLOCK_SIZE];
42 int buffer_ptr;
43 } AudioData;
44
45 static int audio_open(AudioData *s, int is_output)
46 {
47 int audio_fd;
48 int tmp, err;
49
50 /* open linux audio device */
51 if (is_output)
52 audio_fd = open(audio_device, O_WRONLY);
53 else
54 audio_fd = open(audio_device, O_RDONLY);
55 if (audio_fd < 0) {
56 perror(audio_device);
57 return -EIO;
58 }
59
60 /* non blocking mode */
61 fcntl(audio_fd, F_SETFL, O_NONBLOCK);
62
63 s->frame_size = AUDIO_BLOCK_SIZE;
64 #if 0
65 tmp = (NB_FRAGMENTS << 16) | FRAGMENT_BITS;
66 err = ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &tmp);
67 if (err < 0) {
68 perror("SNDCTL_DSP_SETFRAGMENT");
69 }
70 #endif
71
72 /* select format : favour native format */
73 err = ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &tmp);
74
75 #ifdef WORDS_BIGENDIAN
76 if (tmp & AFMT_S16_BE) {
77 tmp = AFMT_S16_BE;
78 } else if (tmp & AFMT_S16_LE) {
79 tmp = AFMT_S16_LE;
80 } else {
81 tmp = 0;
82 }
83 #else
84 if (tmp & AFMT_S16_LE) {
85 tmp = AFMT_S16_LE;
86 } else if (tmp & AFMT_S16_BE) {
87 tmp = AFMT_S16_BE;
88 } else {
89 tmp = 0;
90 }
91 #endif
92
93 switch(tmp) {
94 case AFMT_S16_LE:
95 s->codec_id = CODEC_ID_PCM_S16LE;
96 break;
97 case AFMT_S16_BE:
98 s->codec_id = CODEC_ID_PCM_S16BE;
99 break;
100 default:
101 fprintf(stderr, "Soundcard does not support 16 bit sample format\n");
102 close(audio_fd);
103 return -EIO;
104 }
105 err=ioctl(audio_fd, SNDCTL_DSP_SETFMT, &tmp);
106 if (err < 0) {
107 perror("SNDCTL_DSP_SETFMT");
108 goto fail;
109 }
110
111 tmp = (s->channels == 2);
112 err = ioctl(audio_fd, SNDCTL_DSP_STEREO, &tmp);
113 if (err < 0) {
114 perror("SNDCTL_DSP_STEREO");
115 goto fail;
116 }
117
118 tmp = s->sample_rate;
119 err = ioctl(audio_fd, SNDCTL_DSP_SPEED, &tmp);
120 if (err < 0) {
121 perror("SNDCTL_DSP_SPEED");
122 goto fail;
123 }
124 s->sample_rate = tmp; /* store real sample rate */
125 s->fd = audio_fd;
126
127 return 0;
128 fail:
129 close(audio_fd);
130 return -EIO;
131 }
132
133 static int audio_close(AudioData *s)
134 {
135 close(s->fd);
136 return 0;
137 }
138
139 /* sound output support */
140 static int audio_write_header(AVFormatContext *s1)
141 {
142 AudioData *s;
143 AVStream *st;
144 int ret;
145
146 s = av_mallocz(sizeof(AudioData));
147 if (!s)
148 return -ENOMEM;
149 s1->priv_data = s;
150
151 st = s1->streams[0];
152 s->sample_rate = st->codec.sample_rate;
153 s->channels = st->codec.channels;
154 ret = audio_open(s, 1);
155 if (ret < 0) {
156 free(s);
157 return -EIO;
158 } else {
159 return 0;
160 }
161 }
162
163 static int audio_write_packet(AVFormatContext *s1, int stream_index,
164 UINT8 *buf, int size, int force_pts)
165 {
166 AudioData *s = s1->priv_data;
167 int len, ret;
168
169 while (size > 0) {
170 len = AUDIO_BLOCK_SIZE - s->buffer_ptr;
171 if (len > size)
172 len = size;
173 memcpy(s->buffer + s->buffer_ptr, buf, len);
174 s->buffer_ptr += len;
175 if (s->buffer_ptr >= AUDIO_BLOCK_SIZE) {
176 for(;;) {
177 ret = write(s->fd, s->buffer, AUDIO_BLOCK_SIZE);
178 if (ret != 0)
179 break;
180 if (ret < 0 && (errno != EAGAIN && errno != EINTR))
181 return -EIO;
182 }
183 s->buffer_ptr = 0;
184 }
185 buf += len;
186 size -= len;
187 }
188 return 0;
189 }
190
191 static int audio_write_trailer(AVFormatContext *s1)
192 {
193 AudioData *s = s1->priv_data;
194
195 audio_close(s);
196 free(s);
197 return 0;
198 }
199
200 /* grab support */
201
202 static int audio_read_header(AVFormatContext *s1, AVFormatParameters *ap)
203 {
204 AudioData *s;
205 AVStream *st;
206 int ret;
207
208 if (!ap || ap->sample_rate <= 0 || ap->channels <= 0)
209 return -1;
210
211 s = av_mallocz(sizeof(AudioData));
212 if (!s)
213 return -ENOMEM;
214 st = av_mallocz(sizeof(AVStream));
215 if (!st) {
216 free(s);
217 return -ENOMEM;
218 }
219 s1->priv_data = s;
220 s1->nb_streams = 1;
221 s1->streams[0] = st;
222 s->sample_rate = ap->sample_rate;
223 s->channels = ap->channels;
224
225 ret = audio_open(s, 0);
226 if (ret < 0) {
227 free(st);
228 free(s);
229 return -EIO;
230 } else {
231 /* take real parameters */
232 st->codec.codec_type = CODEC_TYPE_AUDIO;
233 st->codec.codec_id = s->codec_id;
234 st->codec.sample_rate = s->sample_rate;
235 st->codec.channels = s->channels;
236 return 0;
237 }
238 }
239
240 static int audio_read_packet(AVFormatContext *s1, AVPacket *pkt)
241 {
242 AudioData *s = s1->priv_data;
243 int ret;
244
245 if (av_new_packet(pkt, s->frame_size) < 0)
246 return -EIO;
247 for(;;) {
248 ret = read(s->fd, pkt->data, pkt->size);
249 if (ret > 0)
250 break;
251 if (ret == -1 && (errno == EAGAIN || errno == EINTR)) {
252 av_free_packet(pkt);
253 pkt->size = 0;
254 return 0;
255 }
256 if (!(ret == 0 || (ret == -1 && (errno == EAGAIN || errno == EINTR)))) {
257 av_free_packet(pkt);
258 return -EIO;
259 }
260 }
261 pkt->size = ret;
262 return 0;
263 }
264
265 static int audio_read_close(AVFormatContext *s1)
266 {
267 AudioData *s = s1->priv_data;
268
269 audio_close(s);
270 free(s);
271 return 0;
272 }
273
274 AVFormat audio_device_format = {
275 "audio_device",
276 "audio grab and output",
277 "",
278 "",
279 /* XXX: we make the assumption that the soundcard accepts this format */
280 /* XXX: find better solution with "preinit" method, needed also in
281 other formats */
282 #ifdef WORDS_BIGENDIAN
283 CODEC_ID_PCM_S16BE,
284 #else
285 CODEC_ID_PCM_S16LE,
286 #endif
287 CODEC_ID_NONE,
288 audio_write_header,
289 audio_write_packet,
290 audio_write_trailer,
291
292 audio_read_header,
293 audio_read_packet,
294 audio_read_close,
295 NULL,
296 AVFMT_NOFILE,
297 };