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
25 #include <soundcard.h>
27 #include <sys/soundcard.h>
31 #include <sys/ioctl.h>
35 #define AUDIO_BLOCK_SIZE 4096
41 int frame_size; /* in bytes ! */
44 uint8_t buffer[AUDIO_BLOCK_SIZE];
48 static int audio_open(AudioData *s, int is_output, const char *audio_device)
52 char *flip = getenv("AUDIO_FLIP_LEFT");
54 /* open linux audio device */
57 audio_device = "/dev/sound";
59 audio_device = "/dev/dsp";
63 audio_fd = open(audio_device, O_WRONLY);
65 audio_fd = open(audio_device, O_RDONLY);
71 if (flip && *flip == '1') {
75 /* non blocking mode */
77 fcntl(audio_fd, F_SETFL, O_NONBLOCK);
79 s->frame_size = AUDIO_BLOCK_SIZE;
81 tmp = (NB_FRAGMENTS << 16) | FRAGMENT_BITS;
82 err = ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &tmp);
84 perror("SNDCTL_DSP_SETFRAGMENT");
88 /* select format : favour native format */
89 err = ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &tmp);
91 #ifdef WORDS_BIGENDIAN
92 if (tmp & AFMT_S16_BE) {
94 } else if (tmp & AFMT_S16_LE) {
100 if (tmp & AFMT_S16_LE) {
102 } else if (tmp & AFMT_S16_BE) {
111 s->codec_id = CODEC_ID_PCM_S16LE;
114 s->codec_id = CODEC_ID_PCM_S16BE;
117 av_log(NULL, AV_LOG_ERROR, "Soundcard does not support 16 bit sample format\n");
121 err=ioctl(audio_fd, SNDCTL_DSP_SETFMT, &tmp);
123 perror("SNDCTL_DSP_SETFMT");
127 tmp = (s->channels == 2);
128 err = ioctl(audio_fd, SNDCTL_DSP_STEREO, &tmp);
130 perror("SNDCTL_DSP_STEREO");
136 tmp = s->sample_rate;
137 err = ioctl(audio_fd, SNDCTL_DSP_SPEED, &tmp);
139 perror("SNDCTL_DSP_SPEED");
142 s->sample_rate = tmp; /* store real sample rate */
151 static int audio_close(AudioData *s)
157 /* sound output support */
158 static int audio_write_header(AVFormatContext *s1)
160 AudioData *s = s1->priv_data;
165 s->sample_rate = st->codec->sample_rate;
166 s->channels = st->codec->channels;
167 ret = audio_open(s, 1, NULL);
175 static int audio_write_packet(AVFormatContext *s1, AVPacket *pkt)
177 AudioData *s = s1->priv_data;
180 uint8_t *buf= pkt->data;
183 len = AUDIO_BLOCK_SIZE - s->buffer_ptr;
186 memcpy(s->buffer + s->buffer_ptr, buf, len);
187 s->buffer_ptr += len;
188 if (s->buffer_ptr >= AUDIO_BLOCK_SIZE) {
190 ret = write(s->fd, s->buffer, AUDIO_BLOCK_SIZE);
193 if (ret < 0 && (errno != EAGAIN && errno != EINTR))
204 static int audio_write_trailer(AVFormatContext *s1)
206 AudioData *s = s1->priv_data;
214 static int audio_read_header(AVFormatContext *s1, AVFormatParameters *ap)
216 AudioData *s = s1->priv_data;
220 if (!ap || ap->sample_rate <= 0 || ap->channels <= 0)
223 st = av_new_stream(s1, 0);
227 s->sample_rate = ap->sample_rate;
228 s->channels = ap->channels;
230 ret = audio_open(s, 0, ap->device);
236 /* take real parameters */
237 st->codec->codec_type = CODEC_TYPE_AUDIO;
238 st->codec->codec_id = s->codec_id;
239 st->codec->sample_rate = s->sample_rate;
240 st->codec->channels = s->channels;
242 av_set_pts_info(st, 48, 1, 1000000); /* 48 bits pts in us */
246 static int audio_read_packet(AVFormatContext *s1, AVPacket *pkt)
248 AudioData *s = s1->priv_data;
251 struct audio_buf_info abufi;
253 if (av_new_packet(pkt, s->frame_size) < 0)
260 tv.tv_usec = 30 * 1000; /* 30 msecs -- a bit shorter than 1 frame at 30fps */
265 /* This will block until data is available or we get a timeout */
266 (void) select(s->fd + 1, &fds, 0, 0, &tv);
268 ret = read(s->fd, pkt->data, pkt->size);
271 if (ret == -1 && (errno == EAGAIN || errno == EINTR)) {
274 pkt->pts = av_gettime() & ((1LL << 48) - 1);
277 if (!(ret == 0 || (ret == -1 && (errno == EAGAIN || errno == EINTR)))) {
284 /* compute pts of the start of the packet */
285 cur_time = av_gettime();
287 if (ioctl(s->fd, SNDCTL_DSP_GETISPACE, &abufi) == 0) {
288 bdelay += abufi.bytes;
290 /* substract time represented by the number of bytes in the audio fifo */
291 cur_time -= (bdelay * 1000000LL) / (s->sample_rate * s->channels);
293 /* convert to wanted units */
294 pkt->pts = cur_time & ((1LL << 48) - 1);
296 if (s->flip_left && s->channels == 2) {
298 short *p = (short *) pkt->data;
300 for (i = 0; i < ret; i += 4) {
308 static int audio_read_close(AVFormatContext *s1)
310 AudioData *s = s1->priv_data;
316 static AVInputFormat audio_in_format = {
318 "audio grab and output",
324 .flags = AVFMT_NOFILE,
327 static AVOutputFormat audio_out_format = {
329 "audio grab and output",
333 /* XXX: we make the assumption that the soundcard accepts this format */
334 /* XXX: find better solution with "preinit" method, needed also in
336 #ifdef WORDS_BIGENDIAN
345 .flags = AVFMT_NOFILE,
350 av_register_input_format(&audio_in_format);
351 av_register_output_format(&audio_out_format);