aboutsummaryrefslogtreecommitdiffstats
path: root/libavdevice/openal-dec.c
blob: 7aa165ee74e1f4e5a136d6a2f8b189fd7aca57a4 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
/*
 * Copyright (c) 2011 Jonathan Baldwin
 *
 * This file is part of FFmpeg.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/**
 * @file
 * OpenAL 1.1 capture device for libavdevice
 **/

#include <AL/al.h>
#include <AL/alc.h>

#include "libavutil/opt.h"
#include "libavutil/time.h"
#include "libavformat/demux.h"
#include "libavformat/internal.h"
#include "avdevice.h"

typedef struct {
    AVClass *class;
    /** OpenAL capture device context. **/
    ALCdevice *device;
    /** The number of channels in the captured audio. **/
    int channels;
    /** The sample rate (in Hz) of the captured audio. **/
    int sample_rate;
    /** The sample size (in bits) of the captured audio. **/
    int sample_size;
    /** The OpenAL sample format of the captured audio. **/
    ALCenum sample_format;
    /** The number of bytes between two consecutive samples of the same channel/component. **/
    ALCint sample_step;
    /** If true, print a list of capture devices on this system and exit. **/
    int list_devices;
} al_data;

typedef struct {
    ALCenum al_fmt;
    enum AVCodecID codec_id;
    int channels;
} al_format_info;

#define LOWEST_AL_FORMAT FFMIN(FFMIN(AL_FORMAT_MONO8,AL_FORMAT_MONO16),FFMIN(AL_FORMAT_STEREO8,AL_FORMAT_STEREO16))

/**
 * Get information about an AL_FORMAT value.
 * @param al_fmt the AL_FORMAT value to find information about.
 * @return A pointer to a structure containing information about the AL_FORMAT value.
 */
static const inline al_format_info* get_al_format_info(ALCenum al_fmt)
{
    static const al_format_info info_table[] = {
        [AL_FORMAT_MONO8-LOWEST_AL_FORMAT]    = {AL_FORMAT_MONO8, AV_CODEC_ID_PCM_U8, 1},
        [AL_FORMAT_MONO16-LOWEST_AL_FORMAT]   = {AL_FORMAT_MONO16, AV_NE (AV_CODEC_ID_PCM_S16BE, AV_CODEC_ID_PCM_S16LE), 1},
        [AL_FORMAT_STEREO8-LOWEST_AL_FORMAT]  = {AL_FORMAT_STEREO8, AV_CODEC_ID_PCM_U8, 2},
        [AL_FORMAT_STEREO16-LOWEST_AL_FORMAT] = {AL_FORMAT_STEREO16, AV_NE (AV_CODEC_ID_PCM_S16BE, AV_CODEC_ID_PCM_S16LE), 2},
    };

    return &info_table[al_fmt-LOWEST_AL_FORMAT];
}

/**
 * Get the OpenAL error code, translated into an av/errno error code.
 * @param device The ALC device to check for errors.
 * @param error_msg_ret A pointer to a char* in which to return the error message, or NULL if desired.
 * @return The error code, or 0 if there is no error.
 */
static inline int al_get_error(ALCdevice *device, const char** error_msg_ret)
{
    ALCenum error = alcGetError(device);
    if (error_msg_ret)
        *error_msg_ret = (const char*) alcGetString(device, error);
    switch (error) {
    case ALC_NO_ERROR:
        return 0;
    case ALC_INVALID_DEVICE:
        return AVERROR(ENODEV);
        break;
    case ALC_INVALID_CONTEXT:
    case ALC_INVALID_ENUM:
    case ALC_INVALID_VALUE:
        return AVERROR(EINVAL);
        break;
    case ALC_OUT_OF_MEMORY:
        return AVERROR(ENOMEM);
        break;
    default:
        return AVERROR(EIO);
    }
}

/**
 * Print out a list of OpenAL capture devices on this system.
 */
static inline void print_al_capture_devices(void *log_ctx)
{
    const char *devices;

    if (!(devices = alcGetString(NULL, ALC_CAPTURE_DEVICE_SPECIFIER)))
        return;

    av_log(log_ctx, AV_LOG_INFO, "List of OpenAL capture devices on this system:\n");

    for (; *devices != '\0'; devices += strlen(devices) + 1)
        av_log(log_ctx, AV_LOG_INFO, "  %s\n", devices);
}

static int read_header(AVFormatContext *ctx)
{
    al_data *ad = ctx->priv_data;
    static const ALCenum sample_formats[2][2] = {
        { AL_FORMAT_MONO8,  AL_FORMAT_STEREO8  },
        { AL_FORMAT_MONO16, AL_FORMAT_STEREO16 }
    };
    int error = 0;
    const char *error_msg;
    AVStream *st = NULL;
    AVCodecParameters *par = NULL;

    if (ad->list_devices) {
        print_al_capture_devices(ctx);
        return AVERROR_EXIT;
    }

    ad->sample_format = sample_formats[ad->sample_size/8-1][ad->channels-1];

    /* Open device for capture */
    ad->device =
        alcCaptureOpenDevice(ctx->url[0] ? ctx->url : NULL,
                             ad->sample_rate,
                             ad->sample_format,
                             ad->sample_rate); /* Maximum 1 second of sample data to be read at once */

    if (error = al_get_error(ad->device, &error_msg)) goto fail;

    /* Create stream */
    if (!(st = avformat_new_stream(ctx, NULL))) {
        error = AVERROR(ENOMEM);
        goto fail;
    }

    /* We work in microseconds */
    avpriv_set_pts_info(st, 64, 1, 1000000);

    /* Set codec parameters */
    par = st->codecpar;
    par->codec_type = AVMEDIA_TYPE_AUDIO;
    par->sample_rate = ad->sample_rate;
    par->ch_layout.nb_channels = get_al_format_info(ad->sample_format)->channels;
    par->codec_id = get_al_format_info(ad->sample_format)->codec_id;

    /* This is needed to read the audio data */
    ad->sample_step = (av_get_bits_per_sample(get_al_format_info(ad->sample_format)->codec_id) *
                       get_al_format_info(ad->sample_format)->channels) / 8;

    /* Finally, start the capture process */
    alcCaptureStart(ad->device);

    return 0;

fail:
    /* Handle failure */
    if (ad->device)
        alcCaptureCloseDevice(ad->device);
    if (error_msg)
        av_log(ctx, AV_LOG_ERROR, "Cannot open device: %s\n", error_msg);
    return error;
}

static int read_packet(AVFormatContext* ctx, AVPacket *pkt)
{
    al_data *ad = ctx->priv_data;
    int error=0;
    const char *error_msg;
    ALCint nb_samples;

    for (;;) {
        /* Get number of samples available */
        alcGetIntegerv(ad->device, ALC_CAPTURE_SAMPLES, (ALCsizei) sizeof(ALCint), &nb_samples);
        if (error = al_get_error(ad->device, &error_msg)) goto fail;
        if (nb_samples > 0)
            break;
        if (ctx->flags & AVFMT_FLAG_NONBLOCK)
            return AVERROR(EAGAIN);
        av_usleep(1000);
    }

    /* Create a packet of appropriate size */
    if ((error = av_new_packet(pkt, nb_samples*ad->sample_step)) < 0)
        goto fail;
    pkt->pts = av_gettime();

    /* Fill the packet with the available samples */
    alcCaptureSamples(ad->device, pkt->data, nb_samples);
    if (error = al_get_error(ad->device, &error_msg)) goto fail;

    return pkt->size;
fail:
    /* Handle failure */
    if (pkt->data)
        av_packet_unref(pkt);
    if (error_msg)
        av_log(ctx, AV_LOG_ERROR, "Error: %s\n", error_msg);
    return error;
}

static int read_close(AVFormatContext* ctx)
{
    al_data *ad = ctx->priv_data;

    if (ad->device) {
        alcCaptureStop(ad->device);
        alcCaptureCloseDevice(ad->device);
    }
    return 0;
}

#define OFFSET(x) offsetof(al_data, x)

static const AVOption options[] = {
    {"channels", "set number of channels",     OFFSET(channels),     AV_OPT_TYPE_INT, {.i64=2},     1, 2,      AV_OPT_FLAG_DECODING_PARAM },
    {"sample_rate", "set sample rate",         OFFSET(sample_rate),  AV_OPT_TYPE_INT, {.i64=44100}, 1, 192000, AV_OPT_FLAG_DECODING_PARAM },
    {"sample_size", "set sample size",         OFFSET(sample_size),  AV_OPT_TYPE_INT, {.i64=16},    8, 16,     AV_OPT_FLAG_DECODING_PARAM },
    {"list_devices", "list available devices", OFFSET(list_devices), AV_OPT_TYPE_INT, {.i64=0},     0, 1,      AV_OPT_FLAG_DECODING_PARAM, .unit = "list_devices"  },
    {"true",  "", 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, AV_OPT_FLAG_DECODING_PARAM, .unit = "list_devices" },
    {"false", "", 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, AV_OPT_FLAG_DECODING_PARAM, .unit = "list_devices" },
    {NULL},
};

static const AVClass class = {
    .class_name = "openal indev",
    .item_name = av_default_item_name,
    .option = options,
    .version = LIBAVUTIL_VERSION_INT,
    .category = AV_CLASS_CATEGORY_DEVICE_AUDIO_INPUT,
};

const FFInputFormat ff_openal_demuxer = {
    .p.name         = "openal",
    .p.long_name    = NULL_IF_CONFIG_SMALL("OpenAL audio capture device"),
    .p.flags        = AVFMT_NOFILE,
    .p.priv_class   = &class,
    .priv_data_size = sizeof(al_data),
    .read_probe = NULL,
    .read_header = read_header,
    .read_packet = read_packet,
    .read_close = read_close,
};