FFmpeg
audiotoolbox.m
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1 /*
2  * AudioToolbox output device
3  * Copyright (c) 2020 Thilo Borgmann <thilo.borgmann@mail.de>
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  */
21 
22 /**
23  * @file
24  * AudioToolbox output device
25  * @author Thilo Borgmann <thilo.borgmann@mail.de>
26  */
27 
28 #import <AudioToolbox/AudioToolbox.h>
29 #include <pthread.h>
30 
31 #include "libavutil/opt.h"
32 #include "libavformat/internal.h"
33 #include "libavutil/internal.h"
34 #include "avdevice.h"
35 
36 typedef struct
37 {
38  AVClass *class;
39 
40  AudioQueueBufferRef buffer[2];
41  pthread_mutex_t buffer_lock[2];
42  int cur_buf;
43  AudioQueueRef queue;
44 
45  int list_devices;
46  int audio_device_index;
47 
48 } ATContext;
49 
50 static int check_status(AVFormatContext *avctx, OSStatus *status, const char *msg)
51 {
52  if (*status != noErr) {
53  av_log(avctx, AV_LOG_ERROR, "Error: %s (%i)\n", msg, *status);
54  return 1;
55  } else {
56  av_log(avctx, AV_LOG_DEBUG, " OK : %s\n", msg);
57  return 0;
58  }
59 }
60 
61 static void queue_callback(void* atctx, AudioQueueRef inAQ,
62  AudioQueueBufferRef inBuffer)
63 {
64  // unlock the buffer that has just been consumed
65  ATContext *ctx = (ATContext*)atctx;
66  for (int i = 0; i < 2; i++) {
67  if (inBuffer == ctx->buffer[i]) {
68  pthread_mutex_unlock(&ctx->buffer_lock[i]);
69  }
70  }
71 }
72 
73 static av_cold int at_write_header(AVFormatContext *avctx)
74 {
75  ATContext *ctx = (ATContext*)avctx->priv_data;
76  OSStatus err = noErr;
77  CFStringRef device_UID = NULL;
78  AudioDeviceID *devices;
79  int num_devices;
80 
81 
82  // get devices
83  UInt32 data_size = 0;
84  AudioObjectPropertyAddress prop;
85  prop.mSelector = kAudioHardwarePropertyDevices;
86  prop.mScope = kAudioObjectPropertyScopeGlobal;
87  prop.mElement = kAudioObjectPropertyElementMaster;
88  err = AudioObjectGetPropertyDataSize(kAudioObjectSystemObject, &prop, 0, NULL, &data_size);
89  if (check_status(avctx, &err, "AudioObjectGetPropertyDataSize devices"))
90  return AVERROR(EINVAL);
91 
92  num_devices = data_size / sizeof(AudioDeviceID);
93 
94  devices = (AudioDeviceID*)(av_malloc(data_size));
95  err = AudioObjectGetPropertyData(kAudioObjectSystemObject, &prop, 0, NULL, &data_size, devices);
96  if (check_status(avctx, &err, "AudioObjectGetPropertyData devices")) {
97  av_freep(&devices);
98  return AVERROR(EINVAL);
99  }
100 
101  // list devices
102  if (ctx->list_devices) {
103  CFStringRef device_name = NULL;
104  prop.mScope = kAudioDevicePropertyScopeInput;
105 
106  av_log(ctx, AV_LOG_INFO, "CoreAudio devices:\n");
107  for(UInt32 i = 0; i < num_devices; ++i) {
108  // UID
109  data_size = sizeof(device_UID);
110  prop.mSelector = kAudioDevicePropertyDeviceUID;
111  err = AudioObjectGetPropertyData(devices[i], &prop, 0, NULL, &data_size, &device_UID);
112  if (check_status(avctx, &err, "AudioObjectGetPropertyData UID"))
113  continue;
114 
115  // name
116  data_size = sizeof(device_name);
117  prop.mSelector = kAudioDevicePropertyDeviceNameCFString;
118  err = AudioObjectGetPropertyData(devices[i], &prop, 0, NULL, &data_size, &device_name);
119  if (check_status(avctx, &err, "AudioObjecTGetPropertyData name"))
120  continue;
121 
122  av_log(ctx, AV_LOG_INFO, "[%d] %30s, %s\n", i,
123  CFStringGetCStringPtr(device_name, kCFStringEncodingMacRoman),
124  CFStringGetCStringPtr(device_UID, kCFStringEncodingMacRoman));
125  }
126  }
127 
128  // get user-defined device UID or use default device
129  // -audio_device_index overrides any URL given
130  const char *stream_name = avctx->url;
131  if (stream_name && ctx->audio_device_index == -1) {
132  sscanf(stream_name, "%d", &ctx->audio_device_index);
133  }
134 
135  if (ctx->audio_device_index >= 0) {
136  // get UID of selected device
137  data_size = sizeof(device_UID);
138  prop.mSelector = kAudioDevicePropertyDeviceUID;
139  err = AudioObjectGetPropertyData(devices[ctx->audio_device_index], &prop, 0, NULL, &data_size, &device_UID);
140  if (check_status(avctx, &err, "AudioObjecTGetPropertyData UID")) {
141  av_freep(&devices);
142  return AVERROR(EINVAL);
143  }
144  } else {
145  // use default device
146  device_UID = NULL;
147  }
148 
149  av_log(ctx, AV_LOG_DEBUG, "stream_name: %s\n", stream_name);
150  av_log(ctx, AV_LOG_DEBUG, "audio_device_idnex: %i\n", ctx->audio_device_index);
151  av_log(ctx, AV_LOG_DEBUG, "UID: %s\n", CFStringGetCStringPtr(device_UID, kCFStringEncodingMacRoman));
152 
153  // check input stream
154  if (avctx->nb_streams != 1 || avctx->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_AUDIO) {
155  av_log(ctx, AV_LOG_ERROR, "Only a single audio stream is supported.\n");
156  return AVERROR(EINVAL);
157  }
158 
159  av_freep(&devices);
160  AVCodecParameters *codecpar = avctx->streams[0]->codecpar;
161 
162  // audio format
163  AudioStreamBasicDescription device_format = {0};
164  device_format.mSampleRate = codecpar->sample_rate;
165  device_format.mFormatID = kAudioFormatLinearPCM;
166  device_format.mFormatFlags |= (codecpar->format == AV_SAMPLE_FMT_FLT) ? kLinearPCMFormatFlagIsFloat : 0;
167  device_format.mFormatFlags |= (codecpar->codec_id == AV_CODEC_ID_PCM_S8) ? kLinearPCMFormatFlagIsSignedInteger : 0;
168  device_format.mFormatFlags |= (codecpar->codec_id == AV_NE(AV_CODEC_ID_PCM_S16BE, AV_CODEC_ID_PCM_S16LE)) ? kLinearPCMFormatFlagIsSignedInteger : 0;
169  device_format.mFormatFlags |= (codecpar->codec_id == AV_NE(AV_CODEC_ID_PCM_S24BE, AV_CODEC_ID_PCM_S24LE)) ? kLinearPCMFormatFlagIsSignedInteger : 0;
170  device_format.mFormatFlags |= (codecpar->codec_id == AV_NE(AV_CODEC_ID_PCM_S32BE, AV_CODEC_ID_PCM_S32LE)) ? kLinearPCMFormatFlagIsSignedInteger : 0;
171  device_format.mFormatFlags |= (av_sample_fmt_is_planar(codecpar->format)) ? kAudioFormatFlagIsNonInterleaved : 0;
172  device_format.mFormatFlags |= (codecpar->codec_id == AV_CODEC_ID_PCM_F32BE) ? kAudioFormatFlagIsBigEndian : 0;
173  device_format.mFormatFlags |= (codecpar->codec_id == AV_CODEC_ID_PCM_S16BE) ? kAudioFormatFlagIsBigEndian : 0;
174  device_format.mFormatFlags |= (codecpar->codec_id == AV_CODEC_ID_PCM_S24BE) ? kAudioFormatFlagIsBigEndian : 0;
175  device_format.mFormatFlags |= (codecpar->codec_id == AV_CODEC_ID_PCM_S32BE) ? kAudioFormatFlagIsBigEndian : 0;
176  device_format.mChannelsPerFrame = codecpar->channels;
177  device_format.mBitsPerChannel = (codecpar->codec_id == AV_NE(AV_CODEC_ID_PCM_S24BE, AV_CODEC_ID_PCM_S24LE)) ? 24 : (av_get_bytes_per_sample(codecpar->format) << 3);
178  device_format.mBytesPerFrame = (device_format.mBitsPerChannel >> 3) * device_format.mChannelsPerFrame;
179  device_format.mFramesPerPacket = 1;
180  device_format.mBytesPerPacket = device_format.mBytesPerFrame * device_format.mFramesPerPacket;
181  device_format.mReserved = 0;
182 
183  av_log(ctx, AV_LOG_DEBUG, "device_format.mSampleRate = %i\n", codecpar->sample_rate);
184  av_log(ctx, AV_LOG_DEBUG, "device_format.mFormatID = %s\n", "kAudioFormatLinearPCM");
185  av_log(ctx, AV_LOG_DEBUG, "device_format.mFormatFlags |= %s\n", (codecpar->format == AV_SAMPLE_FMT_FLT) ? "kLinearPCMFormatFlagIsFloat" : "0");
186  av_log(ctx, AV_LOG_DEBUG, "device_format.mFormatFlags |= %s\n", (codecpar->codec_id == AV_CODEC_ID_PCM_S8) ? "kLinearPCMFormatFlagIsSignedInteger" : "0");
187  av_log(ctx, AV_LOG_DEBUG, "device_format.mFormatFlags |= %s\n", (codecpar->codec_id == AV_NE(AV_CODEC_ID_PCM_S32BE, AV_CODEC_ID_PCM_S32LE)) ? "kLinearPCMFormatFlagIsSignedInteger" : "0");
188  av_log(ctx, AV_LOG_DEBUG, "device_format.mFormatFlags |= %s\n", (codecpar->codec_id == AV_NE(AV_CODEC_ID_PCM_S16BE, AV_CODEC_ID_PCM_S16LE)) ? "kLinearPCMFormatFlagIsSignedInteger" : "0");
189  av_log(ctx, AV_LOG_DEBUG, "device_format.mFormatFlags |= %s\n", (codecpar->codec_id == AV_NE(AV_CODEC_ID_PCM_S24BE, AV_CODEC_ID_PCM_S24LE)) ? "kLinearPCMFormatFlagIsSignedInteger" : "0");
190  av_log(ctx, AV_LOG_DEBUG, "device_format.mFormatFlags |= %s\n", (av_sample_fmt_is_planar(codecpar->format)) ? "kAudioFormatFlagIsNonInterleaved" : "0");
191  av_log(ctx, AV_LOG_DEBUG, "device_format.mFormatFlags |= %s\n", (codecpar->codec_id == AV_CODEC_ID_PCM_F32BE) ? "kAudioFormatFlagIsBigEndian" : "0");
192  av_log(ctx, AV_LOG_DEBUG, "device_format.mFormatFlags |= %s\n", (codecpar->codec_id == AV_CODEC_ID_PCM_S16BE) ? "kAudioFormatFlagIsBigEndian" : "0");
193  av_log(ctx, AV_LOG_DEBUG, "device_format.mFormatFlags |= %s\n", (codecpar->codec_id == AV_CODEC_ID_PCM_S24BE) ? "kAudioFormatFlagIsBigEndian" : "0");
194  av_log(ctx, AV_LOG_DEBUG, "device_format.mFormatFlags |= %s\n", (codecpar->codec_id == AV_CODEC_ID_PCM_S32BE) ? "kAudioFormatFlagIsBigEndian" : "0");
195  av_log(ctx, AV_LOG_DEBUG, "device_format.mFormatFlags == %i\n", device_format.mFormatFlags);
196  av_log(ctx, AV_LOG_DEBUG, "device_format.mChannelsPerFrame = %i\n", codecpar->channels);
197  av_log(ctx, AV_LOG_DEBUG, "device_format.mBitsPerChannel = %i\n", av_get_bytes_per_sample(codecpar->format) << 3);
198  av_log(ctx, AV_LOG_DEBUG, "device_format.mBytesPerFrame = %i\n", (device_format.mBitsPerChannel >> 3) * codecpar->channels);
199  av_log(ctx, AV_LOG_DEBUG, "device_format.mBytesPerPacket = %i\n", device_format.mBytesPerFrame);
200  av_log(ctx, AV_LOG_DEBUG, "device_format.mFramesPerPacket = %i\n", 1);
201  av_log(ctx, AV_LOG_DEBUG, "device_format.mReserved = %i\n", 0);
202 
203  // create new output queue for the device
204  err = AudioQueueNewOutput(&device_format, queue_callback, ctx,
205  NULL, kCFRunLoopCommonModes,
206  0, &ctx->queue);
207  if (check_status(avctx, &err, "AudioQueueNewOutput")) {
208  if (err == kAudioFormatUnsupportedDataFormatError)
209  av_log(ctx, AV_LOG_ERROR, "Unsupported output format.\n");
210  return AVERROR(EINVAL);
211  }
212 
213  // set user-defined device or leave untouched for default
214  if (device_UID != NULL) {
215  err = AudioQueueSetProperty(ctx->queue, kAudioQueueProperty_CurrentDevice, &device_UID, sizeof(device_UID));
216  if (check_status(avctx, &err, "AudioQueueSetProperty output UID"))
217  return AVERROR(EINVAL);
218  }
219 
220  // start the queue
221  err = AudioQueueStart(ctx->queue, NULL);
222  if (check_status(avctx, &err, "AudioQueueStart"))
223  return AVERROR(EINVAL);
224 
225  // init the mutexes for double-buffering
226  pthread_mutex_init(&ctx->buffer_lock[0], NULL);
227  pthread_mutex_init(&ctx->buffer_lock[1], NULL);
228 
229  return 0;
230 }
231 
232 static int at_write_packet(AVFormatContext *avctx, AVPacket *pkt)
233 {
234  ATContext *ctx = (ATContext*)avctx->priv_data;
235  OSStatus err = noErr;
236 
237  // use the other buffer
238  ctx->cur_buf = !ctx->cur_buf;
239 
240  // lock for writing or wait for the buffer to be available
241  // will be unlocked by queue callback
242  pthread_mutex_lock(&ctx->buffer_lock[ctx->cur_buf]);
243 
244  // (re-)allocate the buffer if not existant or of different size
245  if (!ctx->buffer[ctx->cur_buf] || ctx->buffer[ctx->cur_buf]->mAudioDataBytesCapacity != pkt->size) {
246  err = AudioQueueAllocateBuffer(ctx->queue, pkt->size, &ctx->buffer[ctx->cur_buf]);
247  if (check_status(avctx, &err, "AudioQueueAllocateBuffer")) {
248  pthread_mutex_unlock(&ctx->buffer_lock[ctx->cur_buf]);
249  return AVERROR(ENOMEM);
250  }
251  }
252 
253  AudioQueueBufferRef buf = ctx->buffer[ctx->cur_buf];
254 
255  // copy audio data into buffer and enqueue the buffer
256  memcpy(buf->mAudioData, pkt->data, buf->mAudioDataBytesCapacity);
257  buf->mAudioDataByteSize = buf->mAudioDataBytesCapacity;
258  err = AudioQueueEnqueueBuffer(ctx->queue, buf, 0, NULL);
259  if (check_status(avctx, &err, "AudioQueueEnqueueBuffer")) {
260  pthread_mutex_unlock(&ctx->buffer_lock[ctx->cur_buf]);
261  return AVERROR(EINVAL);
262  }
263 
264  return 0;
265 }
266 
267 static av_cold int at_write_trailer(AVFormatContext *avctx)
268 {
269  ATContext *ctx = (ATContext*)avctx->priv_data;
270  OSStatus err = noErr;
271 
272  pthread_mutex_destroy(&ctx->buffer_lock[0]);
273  pthread_mutex_destroy(&ctx->buffer_lock[1]);
274 
275  err = AudioQueueFlush(ctx->queue);
276  check_status(avctx, &err, "AudioQueueFlush");
277  err = AudioQueueDispose(ctx->queue, true);
278  check_status(avctx, &err, "AudioQueueDispose");
279 
280  return 0;
281 }
282 
283 static const AVOption options[] = {
284  { "list_devices", "list available audio devices", offsetof(ATContext, list_devices), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM },
285  { "audio_device_index", "select audio device by index (starts at 0)", offsetof(ATContext, audio_device_index), AV_OPT_TYPE_INT, {.i64 = -1}, -1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
286  { NULL },
287 };
288 
289 static const AVClass at_class = {
290  .class_name = "AudioToolbox",
291  .item_name = av_default_item_name,
292  .option = options,
293  .version = LIBAVUTIL_VERSION_INT,
294  .category = AV_CLASS_CATEGORY_DEVICE_AUDIO_OUTPUT,
295 };
296 
297 const AVOutputFormat ff_audiotoolbox_muxer = {
298  .name = "audiotoolbox",
299  .long_name = NULL_IF_CONFIG_SMALL("AudioToolbox output device"),
300  .priv_data_size = sizeof(ATContext),
301  .audio_codec = AV_NE(AV_CODEC_ID_PCM_S16BE, AV_CODEC_ID_PCM_S16LE),
302  .video_codec = AV_CODEC_ID_NONE,
303  .write_header = at_write_header,
304  .write_packet = at_write_packet,
305  .write_trailer = at_write_trailer,
306  .flags = AVFMT_NOFILE,
307  .priv_class = &at_class,
308 };
AV_CODEC_ID_PCM_S16LE
@ AV_CODEC_ID_PCM_S16LE
Definition: codec_id.h:314
pthread_mutex_t
_fmutex pthread_mutex_t
Definition: os2threads.h:53
at_write_trailer
static av_cold int at_write_trailer(AVFormatContext *avctx)
Definition: audiotoolbox.m:267
AV_CODEC_ID_PCM_F32BE
@ AV_CODEC_ID_PCM_F32BE
Definition: codec_id.h:334
status
they must not be accessed directly The fifo field contains the frames that are queued in the input for processing by the filter The status_in and status_out fields contains the queued status(EOF or error) of the link
AVOutputFormat::name
const char * name
Definition: avformat.h:504
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:56
AVCodecParameters
This struct describes the properties of an encoded stream.
Definition: codec_par.h:52
ATContext::cur_buf
int cur_buf
Definition: audiotoolbox.m:42
pthread_mutex_init
static av_always_inline int pthread_mutex_init(pthread_mutex_t *mutex, const pthread_mutexattr_t *attr)
Definition: os2threads.h:104
AVFormatContext::streams
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1268
AVPacket::data
uint8_t * data
Definition: packet.h:373
AVOption
AVOption.
Definition: opt.h:247
av_malloc
#define av_malloc(s)
Definition: tableprint_vlc.h:31
at_write_packet
static int at_write_packet(AVFormatContext *avctx, AVPacket *pkt)
Definition: audiotoolbox.m:232
AVCodecParameters::channels
int channels
Audio only.
Definition: codec_par.h:166
AV_CODEC_ID_PCM_S16BE
@ AV_CODEC_ID_PCM_S16BE
Definition: codec_id.h:315
AV_CODEC_ID_PCM_S8
@ AV_CODEC_ID_PCM_S8
Definition: codec_id.h:318
pkt
AVPacket * pkt
Definition: movenc.c:59
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
av_cold
#define av_cold
Definition: attributes.h:90
AV_NE
#define AV_NE(be, le)
Definition: macros.h:33
AV_OPT_FLAG_ENCODING_PARAM
#define AV_OPT_FLAG_ENCODING_PARAM
a generic parameter which can be set by the user for muxing or encoding
Definition: opt.h:277
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
av_sample_fmt_is_planar
int av_sample_fmt_is_planar(enum AVSampleFormat sample_fmt)
Check if the sample format is planar.
Definition: samplefmt.c:112
AV_LOG_DEBUG
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:201
ctx
AVFormatContext * ctx
Definition: movenc.c:48
AVFormatContext
Format I/O context.
Definition: avformat.h:1200
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1095
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
ATContext::list_devices
int list_devices
Definition: audiotoolbox.m:45
av_default_item_name
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: codec_par.h:170
pthread_mutex_unlock
#define pthread_mutex_unlock(a)
Definition: ffprobe.c:68
AVFormatContext::nb_streams
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1256
at_class
static const AVClass at_class
Definition: audiotoolbox.m:289
AV_CODEC_ID_PCM_S24LE
@ AV_CODEC_ID_PCM_S24LE
Definition: codec_id.h:326
at_write_header
static av_cold int at_write_header(AVFormatContext *avctx)
Definition: audiotoolbox.m:73
AVPacket::size
int size
Definition: packet.h:374
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:117
queue_callback
static void queue_callback(void *atctx, AudioQueueRef inAQ, AudioQueueBufferRef inBuffer)
Definition: audiotoolbox.m:61
AVFormatContext::url
char * url
input or output URL.
Definition: avformat.h:1283
AVFMT_NOFILE
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:464
ATContext
Definition: audiotoolbox.m:36
avdevice.h
ATContext::queue
AudioQueueRef queue
Definition: audiotoolbox.m:43
check_status
static int check_status(AVFormatContext *avctx, OSStatus *status, const char *msg)
Definition: audiotoolbox.m:50
AV_LOG_INFO
#define AV_LOG_INFO
Standard information.
Definition: log.h:191
pthread_mutex_destroy
static av_always_inline int pthread_mutex_destroy(pthread_mutex_t *mutex)
Definition: os2threads.h:112
AV_CODEC_ID_NONE
@ AV_CODEC_ID_NONE
Definition: codec_id.h:48
AVOutputFormat
Definition: avformat.h:503
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
av_get_bytes_per_sample
int av_get_bytes_per_sample(enum AVSampleFormat sample_fmt)
Return number of bytes per sample.
Definition: samplefmt.c:106
internal.h
AV_CLASS_CATEGORY_DEVICE_AUDIO_OUTPUT
@ AV_CLASS_CATEGORY_DEVICE_AUDIO_OUTPUT
Definition: log.h:42
AV_CODEC_ID_PCM_S32BE
@ AV_CODEC_ID_PCM_S32BE
Definition: codec_id.h:323
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
options
static const AVOption options[]
Definition: audiotoolbox.m:283
buffer
the frame and frame reference mechanism is intended to as much as expensive copies of that data while still allowing the filters to produce correct results The data is stored in buffers represented by AVFrame structures Several references can point to the same frame buffer
Definition: filter_design.txt:49
AV_OPT_TYPE_INT
@ AV_OPT_TYPE_INT
Definition: opt.h:224
AV_CODEC_ID_PCM_S32LE
@ AV_CODEC_ID_PCM_S32LE
Definition: codec_id.h:322
AVCodecParameters::format
int format
Definition: codec_par.h:84
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
AVPacket
This structure stores compressed data.
Definition: packet.h:350
AV_OPT_TYPE_BOOL
@ AV_OPT_TYPE_BOOL
Definition: opt.h:241
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
ATContext::audio_device_index
int audio_device_index
Definition: audiotoolbox.m:46
ff_audiotoolbox_muxer
const AVOutputFormat ff_audiotoolbox_muxer
Definition: audiotoolbox.m:297
AVFormatContext::priv_data
void * priv_data
Format private data.
Definition: avformat.h:1228
AV_CODEC_ID_PCM_S24BE
@ AV_CODEC_ID_PCM_S24BE
Definition: codec_id.h:327
AV_SAMPLE_FMT_FLT
@ AV_SAMPLE_FMT_FLT
float
Definition: samplefmt.h:63
pthread_mutex_lock
#define pthread_mutex_lock(a)
Definition: ffprobe.c:64
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