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openal-dec.c
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1 /*
2  * Copyright (c) 2011 Jonathan Baldwin
3  *
4  * This file is part of FFmpeg.
5  *
6  * Permission to use, copy, modify, and/or distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
11  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
12  * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
13  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
14  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
15  * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
16  * PERFORMANCE OF THIS SOFTWARE.
17  */
18 
19 /**
20  * @file
21  * OpenAL 1.1 capture device for libavdevice
22  **/
23 
24 #include <AL/al.h>
25 #include <AL/alc.h>
26 
27 #include "libavutil/opt.h"
28 #include "libavutil/time.h"
29 #include "libavformat/internal.h"
30 #include "avdevice.h"
31 
32 typedef struct {
33  AVClass *class;
34  /** OpenAL capture device context. **/
35  ALCdevice *device;
36  /** The number of channels in the captured audio. **/
37  int channels;
38  /** The sample rate (in Hz) of the captured audio. **/
40  /** The sample size (in bits) of the captured audio. **/
42  /** The OpenAL sample format of the captured audio. **/
43  ALCenum sample_format;
44  /** The number of bytes between two consecutive samples of the same channel/component. **/
45  ALCint sample_step;
46  /** If true, print a list of capture devices on this system and exit. **/
48 } al_data;
49 
50 typedef struct {
51  ALCenum al_fmt;
53  int channels;
55 
56 #define LOWEST_AL_FORMAT FFMIN(FFMIN(AL_FORMAT_MONO8,AL_FORMAT_MONO16),FFMIN(AL_FORMAT_STEREO8,AL_FORMAT_STEREO16))
57 
58 /**
59  * Get information about an AL_FORMAT value.
60  * @param al_fmt the AL_FORMAT value to find information about.
61  * @return A pointer to a structure containing information about the AL_FORMAT value.
62  */
63 static const inline al_format_info* get_al_format_info(ALCenum al_fmt)
64 {
65  static const al_format_info info_table[] = {
66  [AL_FORMAT_MONO8-LOWEST_AL_FORMAT] = {AL_FORMAT_MONO8, AV_CODEC_ID_PCM_U8, 1},
67  [AL_FORMAT_MONO16-LOWEST_AL_FORMAT] = {AL_FORMAT_MONO16, AV_NE (AV_CODEC_ID_PCM_S16BE, AV_CODEC_ID_PCM_S16LE), 1},
68  [AL_FORMAT_STEREO8-LOWEST_AL_FORMAT] = {AL_FORMAT_STEREO8, AV_CODEC_ID_PCM_U8, 2},
69  [AL_FORMAT_STEREO16-LOWEST_AL_FORMAT] = {AL_FORMAT_STEREO16, AV_NE (AV_CODEC_ID_PCM_S16BE, AV_CODEC_ID_PCM_S16LE), 2},
70  };
71 
72  return &info_table[al_fmt-LOWEST_AL_FORMAT];
73 }
74 
75 /**
76  * Get the OpenAL error code, translated into an av/errno error code.
77  * @param device The ALC device to check for errors.
78  * @param error_msg_ret A pointer to a char* in which to return the error message, or NULL if desired.
79  * @return The error code, or 0 if there is no error.
80  */
81 static inline int al_get_error(ALCdevice *device, const char** error_msg_ret)
82 {
83  ALCenum error = alcGetError(device);
84  if (error_msg_ret)
85  *error_msg_ret = (const char*) alcGetString(device, error);
86  switch (error) {
87  case ALC_NO_ERROR:
88  return 0;
89  case ALC_INVALID_DEVICE:
90  return AVERROR(ENODEV);
91  break;
92  case ALC_INVALID_CONTEXT:
93  case ALC_INVALID_ENUM:
94  case ALC_INVALID_VALUE:
95  return AVERROR(EINVAL);
96  break;
97  case ALC_OUT_OF_MEMORY:
98  return AVERROR(ENOMEM);
99  break;
100  default:
101  return AVERROR(EIO);
102  }
103 }
104 
105 /**
106  * Print out a list of OpenAL capture devices on this system.
107  */
108 static inline void print_al_capture_devices(void *log_ctx)
109 {
110  const char *devices;
111 
112  if (!(devices = alcGetString(NULL, ALC_CAPTURE_DEVICE_SPECIFIER)))
113  return;
114 
115  av_log(log_ctx, AV_LOG_INFO, "List of OpenAL capture devices on this system:\n");
116 
117  for (; *devices != '\0'; devices += strlen(devices) + 1)
118  av_log(log_ctx, AV_LOG_INFO, " %s\n", devices);
119 }
120 
122 {
123  al_data *ad = ctx->priv_data;
124  static const ALCenum sample_formats[2][2] = {
125  { AL_FORMAT_MONO8, AL_FORMAT_STEREO8 },
126  { AL_FORMAT_MONO16, AL_FORMAT_STEREO16 }
127  };
128  int error = 0;
129  const char *error_msg;
130  AVStream *st = NULL;
131  AVCodecParameters *par = NULL;
132 
133  if (ad->list_devices) {
135  return AVERROR_EXIT;
136  }
137 
138  ad->sample_format = sample_formats[ad->sample_size/8-1][ad->channels-1];
139 
140  /* Open device for capture */
141  ad->device =
142  alcCaptureOpenDevice(ctx->filename[0] ? ctx->filename : NULL,
143  ad->sample_rate,
144  ad->sample_format,
145  ad->sample_rate); /* Maximum 1 second of sample data to be read at once */
146 
147  if (error = al_get_error(ad->device, &error_msg)) goto fail;
148 
149  /* Create stream */
150  if (!(st = avformat_new_stream(ctx, NULL))) {
151  error = AVERROR(ENOMEM);
152  goto fail;
153  }
154 
155  /* We work in microseconds */
156  avpriv_set_pts_info(st, 64, 1, 1000000);
157 
158  /* Set codec parameters */
159  par = st->codecpar;
161  par->sample_rate = ad->sample_rate;
164 
165  /* This is needed to read the audio data */
168 
169  /* Finally, start the capture process */
170  alcCaptureStart(ad->device);
171 
172  return 0;
173 
174 fail:
175  /* Handle failure */
176  if (ad->device)
177  alcCaptureCloseDevice(ad->device);
178  if (error_msg)
179  av_log(ctx, AV_LOG_ERROR, "Cannot open device: %s\n", error_msg);
180  return error;
181 }
182 
184 {
185  al_data *ad = ctx->priv_data;
186  int error=0;
187  const char *error_msg;
188  ALCint nb_samples;
189 
190  /* Get number of samples available */
191  alcGetIntegerv(ad->device, ALC_CAPTURE_SAMPLES, (ALCsizei) sizeof(ALCint), &nb_samples);
192  if (error = al_get_error(ad->device, &error_msg)) goto fail;
193 
194  /* Create a packet of appropriate size */
195  if ((error = av_new_packet(pkt, nb_samples*ad->sample_step)) < 0)
196  goto fail;
197  pkt->pts = av_gettime();
198 
199  /* Fill the packet with the available samples */
200  alcCaptureSamples(ad->device, pkt->data, nb_samples);
201  if (error = al_get_error(ad->device, &error_msg)) goto fail;
202 
203  return pkt->size;
204 fail:
205  /* Handle failure */
206  if (pkt->data)
207  av_packet_unref(pkt);
208  if (error_msg)
209  av_log(ctx, AV_LOG_ERROR, "Error: %s\n", error_msg);
210  return error;
211 }
212 
214 {
215  al_data *ad = ctx->priv_data;
216 
217  if (ad->device) {
218  alcCaptureStop(ad->device);
219  alcCaptureCloseDevice(ad->device);
220  }
221  return 0;
222 }
223 
224 #define OFFSET(x) offsetof(al_data, x)
225 
226 static const AVOption options[] = {
227  {"channels", "set number of channels", OFFSET(channels), AV_OPT_TYPE_INT, {.i64=2}, 1, 2, AV_OPT_FLAG_DECODING_PARAM },
228  {"sample_rate", "set sample rate", OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64=44100}, 1, 192000, AV_OPT_FLAG_DECODING_PARAM },
229  {"sample_size", "set sample size", OFFSET(sample_size), AV_OPT_TYPE_INT, {.i64=16}, 8, 16, AV_OPT_FLAG_DECODING_PARAM },
230  {"list_devices", "list available devices", OFFSET(list_devices), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, AV_OPT_FLAG_DECODING_PARAM, "list_devices" },
231  {"true", "", 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, AV_OPT_FLAG_DECODING_PARAM, "list_devices" },
232  {"false", "", 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, AV_OPT_FLAG_DECODING_PARAM, "list_devices" },
233  {NULL},
234 };
235 
236 static const AVClass class = {
237  .class_name = "openal",
238  .item_name = av_default_item_name,
239  .option = options,
242 };
243 
245  .name = "openal",
246  .long_name = NULL_IF_CONFIG_SMALL("OpenAL audio capture device"),
247  .priv_data_size = sizeof(al_data),
248  .read_probe = NULL,
252  .flags = AVFMT_NOFILE,
253  .priv_class = &class
254 };
#define NULL
Definition: coverity.c:32
enum AVCodecID codec_id
Definition: ffmpeg_vaapi.c:149
AVOption.
Definition: opt.h:245
AVFormatContext * ctx
Definition: movenc-test.c:48
#define LIBAVUTIL_VERSION_INT
Definition: version.h:70
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4405
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3915
static const al_format_info * get_al_format_info(ALCenum al_fmt)
Get information about an AL_FORMAT value.
Definition: openal-dec.c:63
int size
Definition: avcodec.h:1578
static void print_al_capture_devices(void *log_ctx)
Print out a list of OpenAL capture devices on this system.
Definition: openal-dec.c:108
static AVPacket pkt
This struct describes the properties of an encoded stream.
Definition: avcodec.h:3907
Format I/O context.
Definition: avformat.h:1319
ALCdevice * device
OpenAL capture device context.
Definition: openal-dec.c:35
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
int sample_rate
The sample rate (in Hz) of the captured audio.
Definition: openal-dec.c:39
static int read_packet(AVFormatContext *ctx, AVPacket *pkt)
Definition: openal-dec.c:183
AVOptions.
#define OFFSET(x)
Definition: openal-dec.c:224
#define AV_NE(be, le)
Definition: common.h:50
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4043
uint8_t * data
Definition: avcodec.h:1577
ALCenum al_fmt
Definition: openal-dec.c:51
#define av_log(a,...)
Main libavdevice API header.
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: avpacket.c:86
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: avcodec.h:189
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
int av_get_bits_per_sample(enum AVCodecID codec_id)
Return codec bits per sample.
Definition: utils.c:3439
ALCenum sample_format
The OpenAL sample format of the captured audio.
Definition: openal-dec.c:43
av_default_item_name
#define LOWEST_AL_FORMAT
Definition: openal-dec.c:56
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:176
static int read_header(AVFormatContext *ctx)
Definition: openal-dec.c:121
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3911
#define fail()
Definition: checkasm.h:81
char filename[1024]
input or output filename
Definition: avformat.h:1395
static int read_probe(AVProbeData *pd)
Definition: jvdec.c:55
#define AVERROR_EXIT
Immediate exit was requested; the called function should not be restarted.
Definition: error.h:56
int channels
The number of channels in the captured audio.
Definition: openal-dec.c:37
int64_t av_gettime(void)
Get the current time in microseconds.
Definition: time.c:39
Stream structure.
Definition: avformat.h:876
sample_rate
#define AV_LOG_INFO
Standard information.
Definition: log.h:187
static const AVOption options[]
Definition: openal-dec.c:226
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:549
Describe the class of an AVClass context structure.
Definition: log.h:67
#define AV_OPT_FLAG_DECODING_PARAM
a generic parameter which can be set by the user for demuxing or decoding
Definition: opt.h:276
ALCint sample_step
The number of bytes between two consecutive samples of the same channel/component.
Definition: openal-dec.c:45
int sample_size
The sample size (in bits) of the captured audio.
Definition: openal-dec.c:41
static int flags
Definition: cpu.c:47
int sample_rate
Audio only.
Definition: avcodec.h:4025
AVInputFormat ff_openal_demuxer
Definition: openal-dec.c:244
static int al_get_error(ALCdevice *device, const char **error_msg_ret)
Get the OpenAL error code, translated into an av/errno error code.
Definition: openal-dec.c:81
enum AVCodecID codec_id
Definition: openal-dec.c:52
int list_devices
If true, print a list of capture devices on this system and exit.
Definition: openal-dec.c:47
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:476
void * priv_data
Format private data.
Definition: avformat.h:1347
int channels
Audio only.
Definition: avcodec.h:4021
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:660
AVCodecParameters * codecpar
Definition: avformat.h:1006
static int read_close(AVFormatContext *ctx)
Definition: openal-dec.c:213
This structure stores compressed data.
Definition: avcodec.h:1554
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1570