FFmpeg
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/demux.h"
30 #include "libavformat/internal.h"
31 #include "avdevice.h"
32 
33 typedef struct {
34  AVClass *class;
35  /** OpenAL capture device context. **/
36  ALCdevice *device;
37  /** The number of channels in the captured audio. **/
38  int channels;
39  /** The sample rate (in Hz) of the captured audio. **/
41  /** The sample size (in bits) of the captured audio. **/
43  /** The OpenAL sample format of the captured audio. **/
44  ALCenum sample_format;
45  /** The number of bytes between two consecutive samples of the same channel/component. **/
46  ALCint sample_step;
47  /** If true, print a list of capture devices on this system and exit. **/
49 } al_data;
50 
51 typedef struct {
52  ALCenum al_fmt;
54  int channels;
56 
57 #define LOWEST_AL_FORMAT FFMIN(FFMIN(AL_FORMAT_MONO8,AL_FORMAT_MONO16),FFMIN(AL_FORMAT_STEREO8,AL_FORMAT_STEREO16))
58 
59 /**
60  * Get information about an AL_FORMAT value.
61  * @param al_fmt the AL_FORMAT value to find information about.
62  * @return A pointer to a structure containing information about the AL_FORMAT value.
63  */
64 static const inline al_format_info* get_al_format_info(ALCenum al_fmt)
65 {
66  static const al_format_info info_table[] = {
67  [AL_FORMAT_MONO8-LOWEST_AL_FORMAT] = {AL_FORMAT_MONO8, AV_CODEC_ID_PCM_U8, 1},
68  [AL_FORMAT_MONO16-LOWEST_AL_FORMAT] = {AL_FORMAT_MONO16, AV_NE (AV_CODEC_ID_PCM_S16BE, AV_CODEC_ID_PCM_S16LE), 1},
69  [AL_FORMAT_STEREO8-LOWEST_AL_FORMAT] = {AL_FORMAT_STEREO8, AV_CODEC_ID_PCM_U8, 2},
70  [AL_FORMAT_STEREO16-LOWEST_AL_FORMAT] = {AL_FORMAT_STEREO16, AV_NE (AV_CODEC_ID_PCM_S16BE, AV_CODEC_ID_PCM_S16LE), 2},
71  };
72 
73  return &info_table[al_fmt-LOWEST_AL_FORMAT];
74 }
75 
76 /**
77  * Get the OpenAL error code, translated into an av/errno error code.
78  * @param device The ALC device to check for errors.
79  * @param error_msg_ret A pointer to a char* in which to return the error message, or NULL if desired.
80  * @return The error code, or 0 if there is no error.
81  */
82 static inline int al_get_error(ALCdevice *device, const char** error_msg_ret)
83 {
84  ALCenum error = alcGetError(device);
85  if (error_msg_ret)
86  *error_msg_ret = (const char*) alcGetString(device, error);
87  switch (error) {
88  case ALC_NO_ERROR:
89  return 0;
90  case ALC_INVALID_DEVICE:
91  return AVERROR(ENODEV);
92  break;
93  case ALC_INVALID_CONTEXT:
94  case ALC_INVALID_ENUM:
95  case ALC_INVALID_VALUE:
96  return AVERROR(EINVAL);
97  break;
98  case ALC_OUT_OF_MEMORY:
99  return AVERROR(ENOMEM);
100  break;
101  default:
102  return AVERROR(EIO);
103  }
104 }
105 
106 /**
107  * Print out a list of OpenAL capture devices on this system.
108  */
109 static inline void print_al_capture_devices(void *log_ctx)
110 {
111  const char *devices;
112 
113  if (!(devices = alcGetString(NULL, ALC_CAPTURE_DEVICE_SPECIFIER)))
114  return;
115 
116  av_log(log_ctx, AV_LOG_INFO, "List of OpenAL capture devices on this system:\n");
117 
118  for (; *devices != '\0'; devices += strlen(devices) + 1)
119  av_log(log_ctx, AV_LOG_INFO, " %s\n", devices);
120 }
121 
123 {
124  al_data *ad = ctx->priv_data;
125  static const ALCenum sample_formats[2][2] = {
126  { AL_FORMAT_MONO8, AL_FORMAT_STEREO8 },
127  { AL_FORMAT_MONO16, AL_FORMAT_STEREO16 }
128  };
129  int error = 0;
130  const char *error_msg;
131  AVStream *st = NULL;
132  AVCodecParameters *par = NULL;
133 
134  if (ad->list_devices) {
136  return AVERROR_EXIT;
137  }
138 
139  ad->sample_format = sample_formats[ad->sample_size/8-1][ad->channels-1];
140 
141  /* Open device for capture */
142  ad->device =
143  alcCaptureOpenDevice(ctx->url[0] ? ctx->url : NULL,
144  ad->sample_rate,
145  ad->sample_format,
146  ad->sample_rate); /* Maximum 1 second of sample data to be read at once */
147 
148  if (error = al_get_error(ad->device, &error_msg)) goto fail;
149 
150  /* Create stream */
151  if (!(st = avformat_new_stream(ctx, NULL))) {
152  error = AVERROR(ENOMEM);
153  goto fail;
154  }
155 
156  /* We work in microseconds */
157  avpriv_set_pts_info(st, 64, 1, 1000000);
158 
159  /* Set codec parameters */
160  par = st->codecpar;
162  par->sample_rate = ad->sample_rate;
165 
166  /* This is needed to read the audio data */
169 
170  /* Finally, start the capture process */
171  alcCaptureStart(ad->device);
172 
173  return 0;
174 
175 fail:
176  /* Handle failure */
177  if (ad->device)
178  alcCaptureCloseDevice(ad->device);
179  if (error_msg)
180  av_log(ctx, AV_LOG_ERROR, "Cannot open device: %s\n", error_msg);
181  return error;
182 }
183 
185 {
186  al_data *ad = ctx->priv_data;
187  int error=0;
188  const char *error_msg;
189  ALCint nb_samples;
190 
191  for (;;) {
192  /* Get number of samples available */
193  alcGetIntegerv(ad->device, ALC_CAPTURE_SAMPLES, (ALCsizei) sizeof(ALCint), &nb_samples);
194  if (error = al_get_error(ad->device, &error_msg)) goto fail;
195  if (nb_samples > 0)
196  break;
198  return AVERROR(EAGAIN);
199  av_usleep(1000);
200  }
201 
202  /* Create a packet of appropriate size */
203  if ((error = av_new_packet(pkt, nb_samples*ad->sample_step)) < 0)
204  goto fail;
205  pkt->pts = av_gettime();
206 
207  /* Fill the packet with the available samples */
208  alcCaptureSamples(ad->device, pkt->data, nb_samples);
209  if (error = al_get_error(ad->device, &error_msg)) goto fail;
210 
211  return pkt->size;
212 fail:
213  /* Handle failure */
214  if (pkt->data)
216  if (error_msg)
217  av_log(ctx, AV_LOG_ERROR, "Error: %s\n", error_msg);
218  return error;
219 }
220 
222 {
223  al_data *ad = ctx->priv_data;
224 
225  if (ad->device) {
226  alcCaptureStop(ad->device);
227  alcCaptureCloseDevice(ad->device);
228  }
229  return 0;
230 }
231 
232 #define OFFSET(x) offsetof(al_data, x)
233 
234 static const AVOption options[] = {
235  {"channels", "set number of channels", OFFSET(channels), AV_OPT_TYPE_INT, {.i64=2}, 1, 2, AV_OPT_FLAG_DECODING_PARAM },
236  {"sample_rate", "set sample rate", OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64=44100}, 1, 192000, AV_OPT_FLAG_DECODING_PARAM },
237  {"sample_size", "set sample size", OFFSET(sample_size), AV_OPT_TYPE_INT, {.i64=16}, 8, 16, AV_OPT_FLAG_DECODING_PARAM },
238  {"list_devices", "list available devices", OFFSET(list_devices), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, AV_OPT_FLAG_DECODING_PARAM, .unit = "list_devices" },
239  {"true", "", 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, AV_OPT_FLAG_DECODING_PARAM, .unit = "list_devices" },
240  {"false", "", 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, AV_OPT_FLAG_DECODING_PARAM, .unit = "list_devices" },
241  {NULL},
242 };
243 
244 static const AVClass class = {
245  .class_name = "openal indev",
246  .item_name = av_default_item_name,
247  .option = options,
250 };
251 
253  .p.name = "openal",
254  .p.long_name = NULL_IF_CONFIG_SMALL("OpenAL audio capture device"),
255  .p.flags = AVFMT_NOFILE,
256  .p.priv_class = &class,
257  .priv_data_size = sizeof(al_data),
258  .read_probe = NULL,
262 };
error
static void error(const char *err)
Definition: target_bsf_fuzzer.c:32
AV_CODEC_ID_PCM_S16LE
@ AV_CODEC_ID_PCM_S16LE
Definition: codec_id.h:328
av_packet_unref
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: packet.c:427
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
opt.h
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:51
AVCodecParameters
This struct describes the properties of an encoded stream.
Definition: codec_par.h:47
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const struct AVCodec *c)
Add a new stream to a media file.
print_al_capture_devices
static void print_al_capture_devices(void *log_ctx)
Print out a list of OpenAL capture devices on this system.
Definition: openal-dec.c:109
AVPacket::data
uint8_t * data
Definition: packet.h:524
AVOption
AVOption.
Definition: opt.h:357
al_get_error
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:82
read_header
static int read_header(AVFormatContext *ctx)
Definition: openal-dec.c:122
AVChannelLayout::nb_channels
int nb_channels
Number of channels in this layout.
Definition: channel_layout.h:313
sample_rate
sample_rate
Definition: ffmpeg_filter.c:424
avpriv_set_pts_info
void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: avformat.c:853
AV_CODEC_ID_PCM_S16BE
@ AV_CODEC_ID_PCM_S16BE
Definition: codec_id.h:329
fail
#define fail()
Definition: checkasm.h:183
al_data::sample_step
ALCint sample_step
The number of bytes between two consecutive samples of the same channel/component.
Definition: openal-dec.c:46
al_data::sample_format
ALCenum sample_format
The OpenAL sample format of the captured audio.
Definition: openal-dec.c:44
read_close
static int read_close(AVFormatContext *ctx)
Definition: openal-dec.c:221
av_get_bits_per_sample
int av_get_bits_per_sample(enum AVCodecID codec_id)
Return codec bits per sample.
Definition: utils.c:547
AV_CLASS_CATEGORY_DEVICE_AUDIO_INPUT
@ AV_CLASS_CATEGORY_DEVICE_AUDIO_INPUT
Definition: log.h:43
al_format_info::channels
int channels
Definition: openal-dec.c:54
pkt
AVPacket * pkt
Definition: movenc.c:60
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
al_format_info::al_fmt
ALCenum al_fmt
Definition: openal-dec.c:52
AV_NE
#define AV_NE(be, le)
Definition: macros.h:33
av_new_packet
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: packet.c:98
AVFormatContext::flags
int flags
Flags modifying the (de)muxer behaviour.
Definition: avformat.h:1406
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:553
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
ff_openal_demuxer
const FFInputFormat ff_openal_demuxer
Definition: openal-dec.c:252
ctx
AVFormatContext * ctx
Definition: movenc.c:49
channels
channels
Definition: aptx.h:31
codec_id
enum AVCodecID codec_id
Definition: vaapi_decode.c:393
av_usleep
int av_usleep(unsigned usec)
Sleep for a period of time.
Definition: time.c:84
AVFormatContext
Format I/O context.
Definition: avformat.h:1255
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:766
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
NULL
#define NULL
Definition: coverity.c:32
av_default_item_name
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:237
time.h
AVCodecParameters::ch_layout
AVChannelLayout ch_layout
Audio only.
Definition: codec_par.h:180
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: codec_par.h:184
AVCodecID
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: codec_id.h:49
al_data::device
ALCdevice * device
OpenAL capture device context.
Definition: openal-dec.c:36
AVPacket::size
int size
Definition: packet.h:525
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:94
AVFormatContext::url
char * url
input or output URL.
Definition: avformat.h:1371
al_data::sample_rate
int sample_rate
The sample rate (in Hz) of the captured audio.
Definition: openal-dec.c:40
AVFMT_NOFILE
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:468
options
static const AVOption options[]
Definition: openal-dec.c:234
avdevice.h
FFInputFormat::p
AVInputFormat p
The public AVInputFormat.
Definition: demux.h:41
OFFSET
#define OFFSET(x)
Definition: openal-dec.c:232
al_data::list_devices
int list_devices
If true, print a list of capture devices on this system and exit.
Definition: openal-dec.c:48
AV_LOG_INFO
#define AV_LOG_INFO
Standard information.
Definition: log.h:191
read_packet
static int read_packet(AVFormatContext *ctx, AVPacket *pkt)
Definition: openal-dec.c:184
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:517
demux.h
al_format_info
Definition: openal-dec.c:51
AVFMT_FLAG_NONBLOCK
#define AVFMT_FLAG_NONBLOCK
Do not block when reading packets from input.
Definition: avformat.h:1409
AVStream
Stream structure.
Definition: avformat.h:743
AVClass::class_name
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:71
al_data::channels
int channels
The number of channels in the captured audio.
Definition: openal-dec.c:38
AV_OPT_TYPE_INT
@ AV_OPT_TYPE_INT
Definition: opt.h:245
al_format_info::codec_id
enum AVCodecID codec_id
Definition: openal-dec.c:53
al_data::sample_size
int sample_size
The sample size (in bits) of the captured audio.
Definition: openal-dec.c:42
av_gettime
int64_t av_gettime(void)
Get the current time in microseconds.
Definition: time.c:39
AV_OPT_FLAG_DECODING_PARAM
#define AV_OPT_FLAG_DECODING_PARAM
A generic parameter which can be set by the user for demuxing or decoding.
Definition: opt.h:284
read_probe
static int read_probe(const AVProbeData *p)
Definition: cdg.c:30
AV_CODEC_ID_PCM_U8
@ AV_CODEC_ID_PCM_U8
Definition: codec_id.h:333
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:55
AVPacket
This structure stores compressed data.
Definition: packet.h:501
FFInputFormat
Definition: demux.h:37
LOWEST_AL_FORMAT
#define LOWEST_AL_FORMAT
Definition: openal-dec.c:57
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
AVERROR_EXIT
#define AVERROR_EXIT
Immediate exit was requested; the called function should not be restarted.
Definition: error.h:58
get_al_format_info
static const al_format_info * get_al_format_info(ALCenum al_fmt)
Get information about an AL_FORMAT value.
Definition: openal-dec.c:64
AV_OPT_TYPE_CONST
@ AV_OPT_TYPE_CONST
Definition: opt.h:254
AVFormatContext::priv_data
void * priv_data
Format private data.
Definition: avformat.h:1283
al_data
Definition: openal-dec.c:33