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 <linux/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 */
67 fcntl(audio_fd, F_SETFL, O_NONBLOCK);
69 s->frame_size = AUDIO_BLOCK_SIZE;
71 tmp = (NB_FRAGMENTS << 16) | FRAGMENT_BITS;
72 err = ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &tmp);
74 perror("SNDCTL_DSP_SETFRAGMENT");
78 /* select format : favour native format */
79 err = ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &tmp);
81 #ifdef WORDS_BIGENDIAN
82 if (tmp & AFMT_S16_BE) {
84 } else if (tmp & AFMT_S16_LE) {
90 if (tmp & AFMT_S16_LE) {
92 } else if (tmp & AFMT_S16_BE) {
101 s->codec_id = CODEC_ID_PCM_S16LE;
104 s->codec_id = CODEC_ID_PCM_S16BE;
107 fprintf(stderr, "Soundcard does not support 16 bit sample format\n");
111 err=ioctl(audio_fd, SNDCTL_DSP_SETFMT, &tmp);
113 perror("SNDCTL_DSP_SETFMT");
117 tmp = (s->channels == 2);
118 err = ioctl(audio_fd, SNDCTL_DSP_STEREO, &tmp);
120 perror("SNDCTL_DSP_STEREO");
126 tmp = s->sample_rate;
127 err = ioctl(audio_fd, SNDCTL_DSP_SPEED, &tmp);
129 perror("SNDCTL_DSP_SPEED");
132 s->sample_rate = tmp; /* store real sample rate */
141 static int audio_close(AudioData *s)
147 /* sound output support */
148 static int audio_write_header(AVFormatContext *s1)
150 AudioData *s = s1->priv_data;
155 s->sample_rate = st->codec.sample_rate;
156 s->channels = st->codec.channels;
157 ret = audio_open(s, 1);
165 static int audio_write_packet(AVFormatContext *s1, int stream_index,
166 UINT8 *buf, int size, int force_pts)
168 AudioData *s = s1->priv_data;
172 len = AUDIO_BLOCK_SIZE - s->buffer_ptr;
175 memcpy(s->buffer + s->buffer_ptr, buf, len);
176 s->buffer_ptr += len;
177 if (s->buffer_ptr >= AUDIO_BLOCK_SIZE) {
179 ret = write(s->fd, s->buffer, AUDIO_BLOCK_SIZE);
182 if (ret < 0 && (errno != EAGAIN && errno != EINTR))
193 static int audio_write_trailer(AVFormatContext *s1)
195 AudioData *s = s1->priv_data;
203 static int audio_read_header(AVFormatContext *s1, AVFormatParameters *ap)
205 AudioData *s = s1->priv_data;
209 if (!ap || ap->sample_rate <= 0 || ap->channels <= 0)
212 st = av_new_stream(s1, 0);
216 s->sample_rate = ap->sample_rate;
217 s->channels = ap->channels;
219 ret = audio_open(s, 0);
224 /* take real parameters */
225 st->codec.codec_type = CODEC_TYPE_AUDIO;
226 st->codec.codec_id = s->codec_id;
227 st->codec.sample_rate = s->sample_rate;
228 st->codec.channels = s->channels;
233 static int audio_read_packet(AVFormatContext *s1, AVPacket *pkt)
235 AudioData *s = s1->priv_data;
238 if (av_new_packet(pkt, s->frame_size) < 0)
241 ret = read(s->fd, pkt->data, pkt->size);
244 if (ret == -1 && (errno == EAGAIN || errno == EINTR)) {
249 if (!(ret == 0 || (ret == -1 && (errno == EAGAIN || errno == EINTR)))) {
255 if (s->flip_left && s->channels == 2) {
257 short *p = (short *) pkt->data;
259 for (i = 0; i < ret; i += 4) {
267 static int audio_read_close(AVFormatContext *s1)
269 AudioData *s = s1->priv_data;
275 AVInputFormat audio_in_format = {
277 "audio grab and output",
286 AVOutputFormat audio_out_format = {
288 "audio grab and output",
292 /* XXX: we make the assumption that the soundcard accepts this format */
293 /* XXX: find better solution with "preinit" method, needed also in
295 #ifdef WORDS_BIGENDIAN
309 av_register_input_format(&audio_in_format);
310 av_register_output_format(&audio_out_format);