2 * Linux audio play and grab interface
3 * Copyright (c) 2000, 2001 Fabrice Bellard.
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library 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 GNU
13 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 #include <sys/soundcard.h>
27 #include <sys/ioctl.h>
31 const char *audio_device = "/dev/dsp";
33 #define AUDIO_BLOCK_SIZE 4096
39 int frame_size; /* in bytes ! */
42 UINT8 buffer[AUDIO_BLOCK_SIZE];
46 static int audio_open(AudioData *s, int is_output)
50 char *flip = getenv("AUDIO_FLIP_LEFT");
52 /* open linux audio device */
54 audio_fd = open(audio_device, O_WRONLY);
56 audio_fd = open(audio_device, O_RDONLY);
62 if (flip && *flip == '1') {
66 /* non blocking mode */
68 fcntl(audio_fd, F_SETFL, O_NONBLOCK);
70 s->frame_size = AUDIO_BLOCK_SIZE;
72 tmp = (NB_FRAGMENTS << 16) | FRAGMENT_BITS;
73 err = ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &tmp);
75 perror("SNDCTL_DSP_SETFRAGMENT");
79 /* select format : favour native format */
80 err = ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &tmp);
82 #ifdef WORDS_BIGENDIAN
83 if (tmp & AFMT_S16_BE) {
85 } else if (tmp & AFMT_S16_LE) {
91 if (tmp & AFMT_S16_LE) {
93 } else if (tmp & AFMT_S16_BE) {
102 s->codec_id = CODEC_ID_PCM_S16LE;
105 s->codec_id = CODEC_ID_PCM_S16BE;
108 fprintf(stderr, "Soundcard does not support 16 bit sample format\n");
112 err=ioctl(audio_fd, SNDCTL_DSP_SETFMT, &tmp);
114 perror("SNDCTL_DSP_SETFMT");
118 tmp = (s->channels == 2);
119 err = ioctl(audio_fd, SNDCTL_DSP_STEREO, &tmp);
121 perror("SNDCTL_DSP_STEREO");
127 tmp = s->sample_rate;
128 err = ioctl(audio_fd, SNDCTL_DSP_SPEED, &tmp);
130 perror("SNDCTL_DSP_SPEED");
133 s->sample_rate = tmp; /* store real sample rate */
142 static int audio_close(AudioData *s)
148 /* sound output support */
149 static int audio_write_header(AVFormatContext *s1)
151 AudioData *s = s1->priv_data;
156 s->sample_rate = st->codec.sample_rate;
157 s->channels = st->codec.channels;
158 ret = audio_open(s, 1);
166 static int audio_write_packet(AVFormatContext *s1, int stream_index,
167 UINT8 *buf, int size, int force_pts)
169 AudioData *s = s1->priv_data;
173 len = AUDIO_BLOCK_SIZE - s->buffer_ptr;
176 memcpy(s->buffer + s->buffer_ptr, buf, len);
177 s->buffer_ptr += len;
178 if (s->buffer_ptr >= AUDIO_BLOCK_SIZE) {
180 ret = write(s->fd, s->buffer, AUDIO_BLOCK_SIZE);
183 if (ret < 0 && (errno != EAGAIN && errno != EINTR))
194 static int audio_write_trailer(AVFormatContext *s1)
196 AudioData *s = s1->priv_data;
204 static int audio_read_header(AVFormatContext *s1, AVFormatParameters *ap)
206 AudioData *s = s1->priv_data;
210 if (!ap || ap->sample_rate <= 0 || ap->channels <= 0)
213 st = av_new_stream(s1, 0);
217 s->sample_rate = ap->sample_rate;
218 s->channels = ap->channels;
220 ret = audio_open(s, 0);
226 /* take real parameters */
227 st->codec.codec_type = CODEC_TYPE_AUDIO;
228 st->codec.codec_id = s->codec_id;
229 st->codec.sample_rate = s->sample_rate;
230 st->codec.channels = s->channels;
232 av_set_pts_info(s1, 48, 1, 1000000); /* 48 bits pts in us */
236 static int audio_read_packet(AVFormatContext *s1, AVPacket *pkt)
238 AudioData *s = s1->priv_data;
241 struct audio_buf_info abufi;
243 if (av_new_packet(pkt, s->frame_size) < 0)
246 ret = read(s->fd, pkt->data, pkt->size);
249 if (ret == -1 && (errno == EAGAIN || errno == EINTR)) {
254 if (!(ret == 0 || (ret == -1 && (errno == EAGAIN || errno == EINTR)))) {
261 /* compute pts of the start of the packet */
262 cur_time = av_gettime();
264 if (ioctl(s->fd, SNDCTL_DSP_GETISPACE, &abufi) == 0) {
265 bdelay += abufi.bytes;
267 /* substract time represented by the number of bytes in the audio fifo */
268 cur_time -= (bdelay * 1000000LL) / (s->sample_rate * s->channels);
270 /* convert to wanted units */
271 pkt->pts = cur_time & ((1LL << 48) - 1);
273 if (s->flip_left && s->channels == 2) {
275 short *p = (short *) pkt->data;
277 for (i = 0; i < ret; i += 4) {
285 static int audio_read_close(AVFormatContext *s1)
287 AudioData *s = s1->priv_data;
293 static AVInputFormat audio_in_format = {
295 "audio grab and output",
301 .flags = AVFMT_NOFILE,
304 static AVOutputFormat audio_out_format = {
306 "audio grab and output",
310 /* XXX: we make the assumption that the soundcard accepts this format */
311 /* XXX: find better solution with "preinit" method, needed also in
313 #ifdef WORDS_BIGENDIAN
322 .flags = AVFMT_NOFILE,
327 av_register_input_format(&audio_in_format);
328 av_register_output_format(&audio_out_format);