qtsound.m 20.8 KB
Newer Older
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
/*****************************************************************************
* qtsound.m: qtkit (Mac OS X) based audio capture module
*****************************************************************************
* Copyright © 2011 VLC authors and VideoLAN
*
* Authors: Pierre d'Herbemont <pdherbemont@videolan.org>
*          Gustaf Neumann <neumann@wu.ac.at>
*          Michael S. Feurstein <michael.feurstein@wu.ac.at>
*
*****************************************************************************
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1
* of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110, USA
*
*****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_aout.h>

#include <vlc_demux.h>
#include <vlc_dialog.h>

42
#define QTKIT_VERSION_MIN_REQUIRED 70603
43

44 45 46 47 48
#import <QTKit/QTKit.h>

/*****************************************************************************
 * Local prototypes.
 *****************************************************************************/
49 50 51 52
static int Open(vlc_object_t *p_this);
static void Close(vlc_object_t *p_this);
static int Demux(demux_t *p_demux);
static int Control(demux_t *, int, va_list);
53 54 55 56 57 58

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/

vlc_module_begin()
59 60 61 62 63 64 65
set_shortname(N_("QTSound"))
set_description(N_("QuickTime Sound Capture"))
set_category(CAT_INPUT)
set_subcategory(SUBCAT_INPUT_ACCESS)
add_shortcut("qtsound")
set_capability("access_demux", 0)
set_callbacks(Open, Close)
66 67 68 69 70 71 72 73 74 75
vlc_module_end ()


/*****************************************************************************
 * QTKit Bridge
 *****************************************************************************/
@interface VLCDecompressedAudioOutput : QTCaptureDecompressedAudioOutput
{
    demux_t *p_qtsound;
    AudioBuffer *currentAudioBuffer;
Michael Feurstein's avatar
Michael Feurstein committed
76
    block_t *rawAudioData;
77 78 79 80 81 82 83 84
    UInt32 numberOfSamples;
    date_t date;
    mtime_t currentPts;
    mtime_t previousPts;
}
- (id)initWithDemux:(demux_t *)p_demux;
- (void)outputAudioSampleBuffer:(QTSampleBuffer *)sampleBuffer fromConnection:(QTCaptureConnection *)connection;
- (BOOL)checkCurrentAudioBuffer;
Michael Feurstein's avatar
Michael Feurstein committed
85
- (void)freeAudioMem;
86 87 88 89 90 91 92 93 94 95
- (mtime_t)getCurrentPts;
- (void *)getCurrentAudioBufferData;
- (UInt32)getCurrentTotalDataSize;
- (UInt32)getNumberOfSamples;

@end

@implementation VLCDecompressedAudioOutput : QTCaptureDecompressedAudioOutput
- (id)initWithDemux:(demux_t *)p_demux
{
96
    if (self = [super init]) {
97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116
        p_qtsound = p_demux;
        currentAudioBuffer = nil;
        date_Init(&date, 44100, 1);
        date_Set(&date,0);
        currentPts = 0;
        previousPts = 0;
    }
    return self;
}
- (void)dealloc
{
    [super dealloc];
}

- (void)outputAudioSampleBuffer:(QTSampleBuffer *)sampleBuffer fromConnection:(QTCaptureConnection *)connection
{
    AudioBufferList *tempAudioBufferList;
    UInt32 totalDataSize = 0;
    UInt32 count = 0;

117
    @synchronized (self) {
118 119 120 121 122
        numberOfSamples = [sampleBuffer numberOfSamples];
        date_Increment(&date,numberOfSamples);
        currentPts = date_Get(&date);

        tempAudioBufferList = [sampleBuffer audioBufferListWithOptions:0];
123
        if (tempAudioBufferList->mNumberBuffers == 2) {
124 125 126 127
            /*
             * Compute totalDataSize as sum of all data blocks in the
             * audio buffer list:
             */
128
            for (count = 0; count < tempAudioBufferList->mNumberBuffers; count++)
129
                totalDataSize += tempAudioBufferList->mBuffers[count].mDataByteSize;
130

131 132 133
            /*
             * Allocate storage for the interleaved audio data
             */
134
            rawAudioData = malloc(totalDataSize);
135 136
            if (NULL == rawAudioData) {
                msg_Err(p_qtsound, "Raw audiodata could not be allocated");
137 138
                return;
            }
139
        } else {
140 141
            msg_Err(p_qtsound, "Too many or only one channel found: %i.",
                               tempAudioBufferList->mNumberBuffers);
142 143 144 145 146 147 148
            return;
        }

        /*
         * Interleave raw data (provided in two separate channels as
         * F32L) with 2 samples per frame
         */
149
        if (totalDataSize) {
150 151 152 153 154 155 156 157
            unsigned short i;
            const float *b1Ptr, *b2Ptr;
            float *uPtr;

            for (i = 0,
                 uPtr = (float *)rawAudioData,
                 b1Ptr = (const float *) tempAudioBufferList->mBuffers[0].mData,
                 b2Ptr = (const float *) tempAudioBufferList->mBuffers[1].mData;
158
                 i < numberOfSamples; i++) {
159 160
                *uPtr++ = *b1Ptr++;
                *uPtr++ = *b2Ptr++;
161 162
            }

163
            if (currentAudioBuffer == nil) {
164
                currentAudioBuffer = (AudioBuffer *)malloc(sizeof(AudioBuffer));
165 166
                if (NULL == currentAudioBuffer) {
                    msg_Err(p_qtsound, "AudioBuffer could not be allocated.");
167 168 169 170 171 172 173 174 175 176 177 178 179 180 181
                    return;
                }
            }
            currentAudioBuffer->mNumberChannels = 2;
            currentAudioBuffer->mDataByteSize = totalDataSize;
            currentAudioBuffer->mData = rawAudioData;
        }
    }
}

- (BOOL)checkCurrentAudioBuffer
{
    return (currentAudioBuffer) ? 1 : 0;
}

Michael Feurstein's avatar
Michael Feurstein committed
182 183
- (void)freeAudioMem
{
184
    FREENULL(rawAudioData);
Michael Feurstein's avatar
Michael Feurstein committed
185 186
}

187 188 189 190 191
- (mtime_t)getCurrentPts
{
    /* FIXME: can this getter be minimized? */
    mtime_t pts;

192
    if(!currentAudioBuffer || currentPts == previousPts)
193 194
        return 0;

195
    @synchronized (self) {
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
        pts = previousPts = currentPts;
    }

    return (currentAudioBuffer->mData) ? currentPts : 0;
}

- (void *)getCurrentAudioBufferData
{
    return currentAudioBuffer->mData;
}

- (UInt32)getCurrentTotalDataSize
{
    return currentAudioBuffer->mDataByteSize;
}

- (UInt32)getNumberOfSamples
{
    return numberOfSamples;
}

@end

/*****************************************************************************
 * Struct
 *****************************************************************************/

struct demux_sys_t {
    QTCaptureSession * session;
    QTCaptureDevice * audiodevice;
    VLCDecompressedAudioOutput * audiooutput;
    es_out_id_t *p_es_audio;
    int i_audio_max_buffer_size;
};

/*****************************************************************************
 * Open: initialize interface
 *****************************************************************************/
234
static int Open(vlc_object_t *p_this)
235 236 237 238 239 240 241 242 243 244 245 246 247 248
{
    demux_t *p_demux = (demux_t*)p_this;
    demux_sys_t *p_sys;
    es_format_t audiofmt;
    char *psz_uid = NULL;
    int audiocodec;
    bool success;
    NSString *qtk_curraudiodevice_uid;
    NSAutoreleasePool *pool;
    NSArray *myAudioDevices, *audioformat_array;
    QTFormatDescription *audio_format;
    QTCaptureDeviceInput *audioInput;
    NSError *o_returnedAudioError;

249
    if(p_demux->psz_location && *p_demux->psz_location)
250
        psz_uid = p_demux->psz_location;
251 252

    msg_Dbg(p_demux, "qtsound uid = %s", psz_uid);
253 254 255 256
    qtk_curraudiodevice_uid = [[NSString alloc] initWithFormat:@"%s", psz_uid];

    pool = [[NSAutoreleasePool alloc] init];

257 258
    p_demux->p_sys = p_sys = calloc(1, sizeof(demux_sys_t));
    if(!p_sys)
259 260
        return VLC_ENOMEM;

261
    msg_Dbg(p_demux, "qtsound : uid = %s", [qtk_curraudiodevice_uid UTF8String]);
262
    myAudioDevices = [[[QTCaptureDevice inputDevicesWithMediaType:QTMediaTypeSound] arrayByAddingObjectsFromArray:[QTCaptureDevice inputDevicesWithMediaType:QTMediaTypeMuxed]] retain];
263 264
    if([myAudioDevices count] == 0) {
        dialog_FatalWait(p_demux, _("No Audio Input device found"),
265
                         _("Your Mac does not seem to be equipped with a suitable audio input device."
266 267
                     "Please check your connectors and drivers."));
        msg_Err(p_demux, "Can't find any Audio device");
268 269 270

        goto error;
    }
271
    unsigned iaudio;
272
    for (iaudio = 0; iaudio < [myAudioDevices count]; iaudio++) {
273
        QTCaptureDevice *qtk_audioDevice;
274
        qtk_audioDevice = [myAudioDevices objectAtIndex:iaudio];
275 276 277
        msg_Dbg(p_demux, "qtsound audio %u/%lu localizedDisplayName: %s uniqueID: %s", iaudio, [myAudioDevices count], [[qtk_audioDevice localizedDisplayName] UTF8String], [[qtk_audioDevice uniqueID] UTF8String]);
        if ([[[qtk_audioDevice uniqueID]stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] isEqualToString:qtk_curraudiodevice_uid]) {
            msg_Dbg(p_demux, "Device found");
278 279 280 281 282
            break;
        }
    }

    audioInput = nil;
283
    if(iaudio < [myAudioDevices count])
284
        p_sys->audiodevice = [myAudioDevices objectAtIndex:iaudio];
285
    else {
286 287 288 289
        /* cannot find designated audio device, fall back to open default audio device */
        msg_Dbg(p_demux, "Cannot find designated uid audio device as %s. Fall back to open default audio device.", [qtk_curraudiodevice_uid UTF8String]);
        p_sys->audiodevice = [QTCaptureDevice defaultInputDeviceWithMediaType: QTMediaTypeSound];
    }
290 291
    if(!p_sys->audiodevice) {
        dialog_FatalWait(p_demux, _("No audio input device found"),
292
                         _("Your Mac does not seem to be equipped with a suitable audio input device."
293 294
                     "Please check your connectors and drivers."));
        msg_Err(p_demux, "Can't find any Audio device");
295 296 297 298

        goto error;
    }

299 300
    if(![p_sys->audiodevice open: &o_returnedAudioError]) {
        msg_Err(p_demux, "Unable to open the audio capture device (%ld)", [o_returnedAudioError code]);
301 302 303
        goto error;
    }

304 305
    if([p_sys->audiodevice isInUseByAnotherApplication] == YES) {
        msg_Err(p_demux, "default audio capture device is exclusively in use by another application");
306 307 308
        goto error;
    }
    audioInput = [[QTCaptureDeviceInput alloc] initWithDevice: p_sys->audiodevice];
309 310
    if(!audioInput) {
        msg_Err(p_demux, "can't create a valid audio capture input facility");
311
        goto error;
312 313
    } else
        msg_Dbg(p_demux, "created valid audio capture input facility");
314 315

    p_sys->audiooutput = [[VLCDecompressedAudioOutput alloc] initWithDemux:p_demux];
316
    msg_Dbg (p_demux, "initialized audio output");
317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354

    /* Get the formats */
    /*
     FIXME: the format description gathered here does not seem to be the same
     in comparison to the format description collected from the actual sampleBuffer.
     This information needs to be updated some other place. For the time being this shall suffice.

     The following verbose output is an example of what is read from the input device during the below block
     [0x3042138] qtsound demux debug: Audio localized format summary: Linear PCM, 24 bit little-endian signed integer, 2 channels, 44100 Hz
     [0x3042138] qtsound demux debug: Sample Rate: 44100; Format ID: lpcm; Format Flags: 00000004; Bytes per Packet: 8; Frames per Packet: 1; Bytes per Frame: 8; Channels per Frame: 2; Bits per Channel: 24
     [0x3042138] qtsound demux debug: Flag float 0 bigEndian 0 signedInt 1 packed 0 alignedHigh 0 non interleaved 0 non mixable 0
     canonical 0 nativeFloatPacked 0 nativeEndian 0

     However when reading this information from the sampleBuffer during the delegate call from
     - (void)outputAudioSampleBuffer:(QTSampleBuffer *)sampleBuffer fromConnection:(QTCaptureConnection *)connection;
     the following data shows up
     2011-09-23 22:06:03.077 VLC[23070:f103] Audio localized format summary: Linear PCM, 32 bit little-endian floating point, 2 channels, 44100 Hz
     2011-09-23 22:06:03.078 VLC[23070:f103] Sample Rate: 44100; Format ID: lpcm; Format Flags: 00000029; Bytes per Packet: 4; Frames per Packet: 1; Bytes per Frame: 4; Channels per Frame: 2; Bits per Channel: 32
     2011-09-23 22:06:03.078 VLC[23070:f103] Flag float 1 bigEndian 0 signedInt 0 packed 1 alignedHigh 0 non interleaved 1 non mixable 0
     canonical 1 nativeFloatPacked 1 nativeEndian 0

     Note the differences
     24bit vs. 32bit
     little-endian signed integer vs. little-endian floating point
     format flag 00000004 vs. 00000029
     bytes per packet 8 vs. 4
     packed 0 vs. 1
     non interleaved 0 vs. 1 -> this makes a major difference when filling our own buffer
     canonical 0 vs. 1
     nativeFloatPacked 0 vs. 1

     One would assume we'd need to feed the (es_format_t)audiofmt with the data collected here.
     This is not the case. Audio will be transmitted in artefacts, due to wrong information.

     At the moment this data is set manually, however one should consider trying to set this data dynamically
     */
    audioformat_array = [p_sys->audiodevice formatDescriptions];
    audio_format = NULL;
355
    for(int k = 0; k < [audioformat_array count]; k++) {
356
        audio_format = (QTFormatDescription *)[audioformat_array objectAtIndex:k];
357

358 359
        msg_Dbg(p_demux, "Audio localized format summary: %s", [[audio_format localizedFormatSummary] UTF8String]);
        msg_Dbg(p_demux, "Audio format description attributes: %s",[[[audio_format formatDescriptionAttributes] description] UTF8String]);
360 361 362 363 364 365 366 367 368 369 370 371

        AudioStreamBasicDescription asbd = {0};
        NSValue *asbdValue =  [audio_format attributeForKey:QTFormatDescriptionAudioStreamBasicDescriptionAttribute];
        [asbdValue getValue:&asbd];

        char formatIDString[5];
        UInt32 formatID = CFSwapInt32HostToBig (asbd.mFormatID);
        bcopy (&formatID, formatIDString, 4);
        formatIDString[4] = '\0';

        /* kept for development purposes */
#if 0
372
        msg_Dbg(p_demux, "Sample Rate: %.0lf; Format ID: %s; Format Flags: %.8x; Bytes per Packet: %d; Frames per Packet: %d; Bytes per Frame: %d; Channels per Frame: %d; Bits per Channel: %d",
373 374 375 376 377 378 379 380 381
                asbd.mSampleRate,
                formatIDString,
                asbd.mFormatFlags,
                asbd.mBytesPerPacket,
                asbd.mFramesPerPacket,
                asbd.mBytesPerFrame,
                asbd.mChannelsPerFrame,
                asbd.mBitsPerChannel);

382
        msg_Dbg(p_demux, "Flag float %d bigEndian %d signedInt %d packed %d alignedHigh %d non interleaved %d non mixable %d\ncanonical %d nativeFloatPacked %d nativeEndian %d",
383 384 385 386 387 388 389 390 391 392 393
                (asbd.mFormatFlags & kAudioFormatFlagIsFloat) != 0,
                (asbd.mFormatFlags & kAudioFormatFlagIsBigEndian) != 0,
                (asbd.mFormatFlags & kAudioFormatFlagIsSignedInteger) != 0,
                (asbd.mFormatFlags & kAudioFormatFlagIsPacked) != 0,
                (asbd.mFormatFlags & kAudioFormatFlagIsAlignedHigh) != 0,
                (asbd.mFormatFlags & kAudioFormatFlagIsNonInterleaved) != 0,
                (asbd.mFormatFlags & kAudioFormatFlagIsNonMixable) != 0,

                (asbd.mFormatFlags & kAudioFormatFlagsCanonical) != 0,
                (asbd.mFormatFlags & kAudioFormatFlagsNativeFloatPacked) != 0,
                (asbd.mFormatFlags & kAudioFormatFlagsNativeEndian) != 0
394
               );
395 396 397
#endif
    }

398
    if([audioformat_array count])
399
        audio_format = [audioformat_array objectAtIndex:0];
400 401
    else
        goto error;
402 403 404

    /* Now we can init */
    audiocodec = VLC_CODEC_FL32;
405
    es_format_Init(&audiofmt, AUDIO_ES, audiocodec);
406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427

    audiofmt.audio.i_format = audiocodec;
    audiofmt.audio.i_rate = 44100;
    /*
     * i_physical_channels Describes the channels configuration of the
     * samples (ie. number of channels which are available in the
     * buffer, and positions).
     */
    audiofmt.audio.i_physical_channels = AOUT_CHAN_RIGHT | AOUT_CHAN_LEFT;
    /*
     * i_original_channels Describes from which original channels,
     * before downmixing, the buffer is derived.
     */
    audiofmt.audio.i_original_channels = AOUT_CHAN_RIGHT | AOUT_CHAN_LEFT;
    /*
     * Please note that it may be completely arbitrary - buffers are not
     * obliged to contain a integral number of so-called "frames". It's
     * just here for the division:
     * buffer_size = i_nb_samples * i_bytes_per_frame / i_frame_length
     */
    audiofmt.audio.i_bitspersample = 32;
    audiofmt.audio.i_channels = 2;
428
    audiofmt.audio.i_blockalign = audiofmt.audio.i_channels * (audiofmt.audio.i_bitspersample / 8);
429
    audiofmt.i_bitrate = audiofmt.audio.i_channels * audiofmt.audio.i_rate * audiofmt.audio.i_bitspersample;
430
    p_sys->i_audio_max_buffer_size = audiofmt.i_bitrate;
431 432 433 434

    p_sys->session = [[QTCaptureSession alloc] init];

    success = [p_sys->session addInput:audioInput error: &o_returnedAudioError];
435 436
    if(!success) {
        msg_Err(p_demux, "the audio capture device could not be added to capture session (%ld)", [o_returnedAudioError code]);
437 438 439 440
        goto error;
    }

    success = [p_sys->session addOutput:p_sys->audiooutput error: &o_returnedAudioError];
441 442
    if(!success) {
        msg_Err(p_demux, "audio output could not be added to capture session (%ld)", [o_returnedAudioError code]);
443 444 445 446 447 448 449 450 451 452 453 454
        goto error;
    }

    [p_sys->session startRunning];

    /* Set up p_demux */
    p_demux->pf_demux = Demux;
    p_demux->pf_control = Control;
    p_demux->info.i_update = 0;
    p_demux->info.i_title = 0;
    p_demux->info.i_seekpoint = 0;

455 456
    msg_Dbg(p_demux, "New audio es %d channels %dHz",
            audiofmt.audio.i_channels, audiofmt.audio.i_rate);
457

458
    p_sys->p_es_audio = es_out_Add(p_demux->out, &audiofmt);
459 460 461 462

    [audioInput release];
    [pool release];

463
    msg_Dbg(p_demux, "QTSound: We have an audio device ready!");
464 465 466 467 468 469

    return VLC_SUCCESS;
error:
    [audioInput release];
    [pool release];

470
    free(p_sys);
471 472 473 474 475 476 477

    return VLC_EGENERIC;
}

/*****************************************************************************
 * Close: destroy interface
 *****************************************************************************/
478
static void Close(vlc_object_t *p_this)
479 480 481 482 483 484 485 486 487
{
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    demux_t *p_demux = (demux_t*)p_this;
    demux_sys_t *p_sys = p_demux->p_sys;

    [p_sys->session performSelectorOnMainThread:@selector(stopRunning) withObject:nil waitUntilDone:NO];
    [p_sys->audiooutput performSelectorOnMainThread:@selector(release) withObject:nil waitUntilDone:NO];
    [p_sys->session performSelectorOnMainThread:@selector(release) withObject:nil waitUntilDone:NO];

488
    free(p_sys);
489 490 491 492 493 494 495

    [pool release];
}

/*****************************************************************************
 * Demux:
 *****************************************************************************/
496
static int Demux(demux_t *p_demux)
497 498
{
    demux_sys_t *p_sys = p_demux->p_sys;
499
    block_t *p_blocka = nil;
500 501 502 503
    NSAutoreleasePool *pool;



504 505
    @synchronized (p_sys->audiooutput) {
        if ([p_sys->audiooutput checkCurrentAudioBuffer]) {
506 507 508 509 510 511 512 513 514
            unsigned i_buffer_size = [p_sys->audiooutput getCurrentTotalDataSize];
            p_blocka = block_Alloc(i_buffer_size);

            if(!p_blocka) {
                msg_Err(p_demux, "cannot get audio block");
                return 0;
            }

            memcpy(p_blocka->p_buffer, [p_sys->audiooutput getCurrentAudioBufferData], i_buffer_size);
515
            p_blocka->i_nb_samples = [p_sys->audiooutput getNumberOfSamples];
516
            p_blocka->i_pts = [p_sys->audiooutput getCurrentPts];
517 518

            [p_sys->audiooutput freeAudioMem];
519 520 521
        }
    }

522 523 524 525 526 527
    if (p_blocka) {
        if (!p_blocka->i_pts) {
            // Nothing to transfer yet, just forget
            msleep(10000);
            return 1;
        }
528

529 530
        es_out_Control(p_demux->out, ES_OUT_SET_PCR, p_blocka->i_pts);
        es_out_Send(p_demux->out, p_sys->p_es_audio, p_blocka);
531 532 533 534 535 536 537 538
    }

    return 1;
}

/*****************************************************************************
 * Control:
 *****************************************************************************/
539
static int Control(demux_t *p_demux, int i_query, va_list args)
540 541 542 543
{
    bool *pb;
    int64_t *pi64;

544
    switch(i_query) {
545 546 547 548 549
            /* Special for access_demux */
        case DEMUX_CAN_PAUSE:
        case DEMUX_CAN_SEEK:
        case DEMUX_SET_PAUSE_STATE:
        case DEMUX_CAN_CONTROL_PACE:
550
            pb = (bool*)va_arg(args, bool *);
551 552 553 554
            *pb = false;
            return VLC_SUCCESS;

        case DEMUX_GET_PTS_DELAY:
555 556
            pi64 = (int64_t*)va_arg(args, int64_t *);
            *pi64 = INT64_C(1000) * var_InheritInteger(p_demux, "live-caching");
557 558 559 560 561 562 563
            return VLC_SUCCESS;

        default:
            return VLC_EGENERIC;
    }
    return VLC_EGENERIC;
}