FFmpeg: libavdevice/sndio.c Source File

FFmpeg

[フレーム]

libavdevice

sndio.c

Go to the documentation of this file.

1 /*

2 * sndio play and grab interface

4 *

5 * This file is part of FFmpeg.

6 *

7 * FFmpeg 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 * FFmpeg 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 FFmpeg; if not, write to the Free Software

19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

20 */

22 #include <stdint.h>

23 #include <sndio.h>

25 #include "avdevice.h"

27 #include "libavdevice/sndio.h"

29 static inline void movecb(void *addr, int delta)

30 {

31 SndioData *s = addr;

33 s->hwpos += delta * s->channels * s->bps;

34 }

36 av_cold int ff_sndio_open(AVFormatContext *s1, int is_output,

37 const char *audio_device)

38 {

39 SndioData *s = s1->priv_data;

40 struct sio_hdl *hdl;

41 struct sio_par par;

43 hdl = sio_open(audio_device, is_output ? SIO_PLAY : SIO_REC, 0);

44 if (!hdl) {

45 av_log(s1, AV_LOG_ERROR, "Could not open sndio device\n");

46 return AVERROR(EIO);

47 }

49 sio_initpar(&par);

51 par.bits = 16;

52 par.sig = 1;

53 par.le = SIO_LE_NATIVE;

55 if (is_output)

56 par.pchan = s->channels;

57 else

58 par.rchan = s->channels;

59 par.rate = s->sample_rate;

61 if (!sio_setpar(hdl, &par) || !sio_getpar(hdl, &par)) {

62 av_log(s1, AV_LOG_ERROR, "Impossible to set sndio parameters, "

63 "channels: %d sample rate: %d\n", s->channels, s->sample_rate);

64 goto fail;

65 }

67 if (par.bits != 16 || par.sig != 1 ||

68 (is_output && (par.pchan != s->channels)) ||

69 (!is_output && (par.rchan != s->channels)) ||

70 (par.rate != s->sample_rate)) {

71 av_log(s1, AV_LOG_ERROR, "Could not set appropriate sndio parameters, "

72 "channels: %d sample rate: %d\n", s->channels, s->sample_rate);

73 goto fail;

74 }

76 s->buffer_size = par.round * par.bps *

77 (is_output ? par.pchan : par.rchan);

79 if (is_output) {

80 s->buffer = av_malloc(s->buffer_size);

81 if (!s->buffer) {

82 av_log(s1, AV_LOG_ERROR, "Could not allocate buffer\n");

83 goto fail;

84 }

85 }

87 s->codec_id = par.le ? AV_CODEC_ID_PCM_S16LE : AV_CODEC_ID_PCM_S16BE;

88 s->channels = is_output ? par.pchan : par.rchan;

89 s->sample_rate = par.rate;

90 s->bps = par.bps;

92 sio_onmove(hdl, movecb, s);

94 if (!sio_start(hdl)) {

95 av_log(s1, AV_LOG_ERROR, "Could not start sndio\n");

96 goto fail;

97 }

99 s->hdl = hdl;

100

101 return 0;

102

103 fail:

104 av_freep(&s->buffer);

105

106 if (hdl)

107 sio_close(hdl);

108

109 return AVERROR(EIO);

110 }

111

112 int ff_sndio_close(SndioData *s)

113 {

114 av_freep(&s->buffer);

115

116 if (s->hdl)

117 sio_close(s->hdl);

118

119 return 0;

120 }

AV_CODEC_ID_PCM_S16LE

@ AV_CODEC_ID_PCM_S16LE

Definition: codec_id.h:314

AVERROR

Filter the word "frame" indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions

ff_sndio_open

av_cold int ff_sndio_open(AVFormatContext *s1, int is_output, const char *audio_device)

Definition: sndio.c:36

sndio.h

av_malloc

#define av_malloc(s)

Definition: tableprint_vlc.h:31

movecb

static void movecb(void *addr, int delta)

Definition: sndio.c:29

AV_CODEC_ID_PCM_S16BE

@ AV_CODEC_ID_PCM_S16BE