]> git.sesse.net Git - vlc/blobdiff - modules/audio_output/opensles_android.c
opensles: resample if original sampling rate is not accepted
[vlc] / modules / audio_output / opensles_android.c
index 147d44ad812991dabe3b1a9ea0a70ce8e1852412..9c80495dfdb0cd4a900cbc68cb0456a1b106dbe7 100644 (file)
 #include <SLES/OpenSLES.h>
 #include <SLES/OpenSLES_Android.h>
 
+#define OPENSLES_BUFFERS 255 /* maximum number of buffers */
+#define OPENSLES_BUFLEN  10   /* ms */
+/*
+ * 10ms of precision when mesasuring latency should be enough,
+ * with 255 buffers we can buffer 2.55s of audio.
+ */
+
+#define CHECK_OPENSL_ERROR(msg)                \
+    if (unlikely(result != SL_RESULT_SUCCESS)) \
+    {                                          \
+        msg_Err(aout, msg" (%lu)", result);    \
+        goto error;                            \
+    }
+
+typedef SLresult (*slCreateEngine_t)(
+        SLObjectItf*, SLuint32, const SLEngineOption*, SLuint32,
+        const SLInterfaceID*, const SLboolean*);
+
 #define Destroy(a) (*a)->Destroy(a);
 #define SetPlayState(a, b) (*a)->SetPlayState(a, b)
 #define RegisterCallback(a, b, c) (*a)->RegisterCallback(a, b, c)
 #define SetMute(a, b) (*a)->SetMute(a, b)
 
 /*****************************************************************************
- * aout_sys_t: audio output method descriptor
- *****************************************************************************
- * This structure is part of the audio output thread descriptor.
- * It describes the direct sound specific properties of an audio device.
+ *
  *****************************************************************************/
 struct aout_sys_t
 {
+    /* OpenSL objects */
     SLObjectItf                     engineObject;
     SLObjectItf                     outputMixObject;
     SLAndroidSimpleBufferQueueItf   playerBufferQueue;
     SLObjectItf                     playerObject;
     SLVolumeItf                     volumeItf;
-
+    SLEngineItf                     engineEngine;
     SLPlayItf                       playerPlay;
 
-    vlc_mutex_t                     lock;
-    mtime_t                         length;
+    /* OpenSL symbols */
+    void                           *p_so_handle;
+
+    slCreateEngine_t                slCreateEnginePtr;
+    SLInterfaceID                   SL_IID_ENGINE;
+    SLInterfaceID                   SL_IID_ANDROIDSIMPLEBUFFERQUEUE;
+    SLInterfaceID                   SL_IID_VOLUME;
+    SLInterfaceID                   SL_IID_PLAY;
 
-    int                             buffers;
-    mtime_t                         last_callback;
+    /* */
+
+    vlc_mutex_t                     lock;
 
     /* audio buffered through opensles */
-    block_t                        *p_chain;
-    block_t                       **pp_last;
+    uint8_t                        *buf;
+    size_t                          samples_per_buf;
+    int                             next_buf;
+
+    int                             rate;
+
+    /* if we can measure latency already */
+    bool                            started;
 
     /* audio not yet buffered through opensles */
     block_t                        *p_buffer_chain;
     block_t                       **pp_buffer_last;
-
-    void                           *p_so_handle;
-    audio_sample_format_t           format;
+    size_t                          samples;
 };
 
 /*****************************************************************************
  * Local prototypes.
  *****************************************************************************/
-static int  Open        ( vlc_object_t * );
+static int  Open  (vlc_object_t *);
+static void Close (vlc_object_t *);
 
 /*****************************************************************************
  * Module descriptor
  *****************************************************************************/
 
 vlc_module_begin ()
-    set_description( N_("OpenSLES audio output") )
-    set_shortname( N_("OpenSLES") )
-    set_category( CAT_AUDIO )
-    set_subcategory( SUBCAT_AUDIO_AOUT )
-
-    set_capability( "audio output", 170 )
-    add_shortcut( "opensles", "android" )
-    set_callbacks( Open, NULL )
+    set_description(N_("OpenSLES audio output"))
+    set_shortname(N_("OpenSLES"))
+    set_category(CAT_AUDIO)
+    set_subcategory(SUBCAT_AUDIO_AOUT)
+
+    set_capability("audio output", 170)
+    add_shortcut("opensles", "android")
+    set_callbacks(Open, Close)
 vlc_module_end ()
 
+/*****************************************************************************
+ *
+ *****************************************************************************/
+
+static inline int bytesPerSample(void)
+{
+    return 2 /* S16 */ * 2 /* stereo */;
+}
 
-static void Clean( aout_sys_t *p_sys )
+static int TimeGet(audio_output_t* aout, mtime_t* restrict drift)
 {
-    if( p_sys->playerObject )
-        Destroy( p_sys->playerObject );
-    if( p_sys->outputMixObject )
-        Destroy( p_sys->outputMixObject );
-    if( p_sys->engineObject )
-        Destroy( p_sys->engineObject );
+    aout_sys_t *sys = aout->sys;
+
+    SLAndroidSimpleBufferQueueState st;
+    SLresult res = GetState(sys->playerBufferQueue, &st);
+    if (unlikely(res != SL_RESULT_SUCCESS)) {
+        msg_Err(aout, "Could not query buffer queue state in TimeGet (%lu)", res);
+        return -1;
+    }
 
-    if( p_sys->p_so_handle )
-        dlclose( p_sys->p_so_handle );
+    vlc_mutex_lock(&sys->lock);
+    bool started = sys->started;
+    vlc_mutex_unlock(&sys->lock);
 
-    free( p_sys );
+    if (!started)
+        return -1;
+
+    *drift = (CLOCK_FREQ * OPENSLES_BUFLEN * st.count / 1000)
+        + sys->samples * CLOCK_FREQ / sys->rate;
+
+    msg_Dbg(aout, "latency %"PRId64" ms, %d/%d buffers", *drift / 1000,
+        (int)st.count, OPENSLES_BUFFERS);
+
+    return 0;
 }
 
-static void Flush(audio_output_t *p_aout, bool drain)
+static void Flush(audio_output_t *aout, bool drain)
 {
-    aout_sys_t *p_sys = p_aout->sys;
+    aout_sys_t *sys = aout->sys;
 
     if (drain) {
         mtime_t delay;
-        vlc_mutex_lock( &p_sys->lock );
-        delay = p_sys->length;
-        vlc_mutex_unlock( &p_sys->lock );
-        msleep(delay);
+        if (!TimeGet(aout, &delay))
+            msleep(delay);
     } else {
-        vlc_mutex_lock( &p_sys->lock );
-        SetPlayState( p_sys->playerPlay, SL_PLAYSTATE_STOPPED );
-        Clear( p_sys->playerBufferQueue );
-        SetPlayState( p_sys->playerPlay, SL_PLAYSTATE_PLAYING );
-
-        p_sys->length = 0;
+        vlc_mutex_lock(&sys->lock);
+        SetPlayState(sys->playerPlay, SL_PLAYSTATE_STOPPED);
+        Clear(sys->playerBufferQueue);
+        SetPlayState(sys->playerPlay, SL_PLAYSTATE_PLAYING);
 
         /* release audio data not yet written to opensles */
-        block_ChainRelease( p_sys->p_buffer_chain );
-        p_sys->p_buffer_chain = NULL;
-        p_sys->pp_buffer_last = &p_sys->p_buffer_chain;
+        block_ChainRelease(sys->p_buffer_chain);
+        sys->p_buffer_chain = NULL;
+        sys->pp_buffer_last = &sys->p_buffer_chain;
 
-        /* release audio data written to opensles, but not yet
-         * played on hardware */
-        block_ChainRelease( p_sys->p_chain );
-        p_sys->p_chain = NULL;
-        p_sys->pp_last = &p_sys->p_chain;
+        sys->samples = 0;
+        sys->started = false;
 
-        vlc_mutex_unlock( &p_sys->lock );
+        vlc_mutex_unlock(&sys->lock);
     }
 }
 
 static int VolumeSet(audio_output_t *aout, float vol)
 {
+    if (!aout->sys->volumeItf)
+        return -1;
+
     /* Convert UI volume to linear factor (cube) */
     vol = vol * vol * vol;
 
@@ -177,222 +221,147 @@ static int VolumeSet(audio_output_t *aout, float vol)
 
 static int MuteSet(audio_output_t *aout, bool mute)
 {
+    if (!aout->sys->volumeItf)
+        return -1;
+
     SLresult r = SetMute(aout->sys->volumeItf, mute);
     return (r == SL_RESULT_SUCCESS) ? 0 : -1;
 }
 
-static void Pause(audio_output_t *p_aout, bool pause, mtime_t date)
+static void Pause(audio_output_t *aout, bool pause, mtime_t date)
 {
     (void)date;
-    aout_sys_t *p_sys = p_aout->sys;
-    SetPlayState( p_sys->playerPlay,
-        pause ? SL_PLAYSTATE_PAUSED : SL_PLAYSTATE_PLAYING );
+    aout_sys_t *sys = aout->sys;
+    SetPlayState(sys->playerPlay,
+        pause ? SL_PLAYSTATE_PAUSED : SL_PLAYSTATE_PLAYING);
 }
 
-static int TimeGet(audio_output_t* p_aout, mtime_t* restrict drift)
+static int WriteBuffer(audio_output_t *aout)
 {
-    aout_sys_t *p_sys = p_aout->sys;
+    aout_sys_t *sys = aout->sys;
+    const size_t unit_size = sys->samples_per_buf * bytesPerSample();
 
-    vlc_mutex_lock( &p_sys->lock );
-    mtime_t delay = p_sys->length;
-    mtime_t last_callback = p_sys->last_callback;
-    vlc_mutex_unlock( &p_sys->lock );
+    block_t *b = sys->p_buffer_chain;
+    if (!b)
+        return false;
 
-    if (last_callback != 0)
-        delay += last_callback - mdate();
+    /* Check if we can fill at least one buffer unit by chaining blocks */
+    if (b->i_buffer < unit_size) {
+        if (!b->p_next)
+            return false;
+        ssize_t needed = unit_size - b->i_buffer;
+        for (block_t *next = b->p_next; next; next = next->p_next) {
+            needed -= next->i_buffer;
+            if (needed <= 0)
+                break;
+        }
+
+        if (needed > 0)
+            return false;
+    }
 
     SLAndroidSimpleBufferQueueState st;
-    SLresult res = GetState(p_sys->playerBufferQueue, &st);
+    SLresult res = GetState(sys->playerBufferQueue, &st);
     if (unlikely(res != SL_RESULT_SUCCESS)) {
-        msg_Err(p_aout, "Could not query buffer queue state in TimeGet (%lu)", res);
-        return -1;
+        msg_Err(aout, "Could not query buffer queue state in %s (%lu)", __func__, res);
+        return false;
     }
 
-    if (delay == 0 || st.count == 0)
-        return -1;
-
-    *drift = delay;
-    return 0;
-}
-
-static int WriteBuffer(audio_output_t *p_aout)
-{
-    aout_sys_t *p_sys = p_aout->sys;
-
-    block_t *b = p_sys->p_buffer_chain;
-    if (!b)
+    if (st.count == OPENSLES_BUFFERS)
         return false;
 
-    if (!b->i_length)
-        b->i_length = (mtime_t)(b->i_buffer / 2 / p_sys->format.i_channels) * CLOCK_FREQ / p_sys->format.i_rate;
-
-    /* If something bad happens, we must remove this buffer from the FIFO */
-    block_t **pp_last_saved = p_sys->pp_last;
-    block_t *p_last_saved = *pp_last_saved;
-    block_t *next_saved = b->p_next;
-    b->p_next = NULL;
+    size_t done = 0;
+    while (done < unit_size) {
+        size_t cur = b->i_buffer;
+        if (cur > unit_size - done)
+            cur = unit_size - done;
+
+        memcpy(&sys->buf[unit_size * sys->next_buf + done], b->p_buffer, cur);
+        b->i_buffer -= cur;
+        b->p_buffer += cur;
+        done += cur;
+
+        block_t *next = b->p_next;
+        if (b->i_buffer == 0) {
+            block_Release(b);
+            b = NULL;
+        }
+
+        if (done == unit_size)
+            break;
+        else
+            b = next;
+    }
 
-    /* Put this block in the list of audio already written to opensles */
-    block_ChainLastAppend( &p_sys->pp_last, b );
+    sys->p_buffer_chain = b;
+    if (!b)
+        sys->pp_buffer_last = &sys->p_buffer_chain;
 
-    mtime_t len = b->i_length;
-    p_sys->length += len;
-    block_t *next = b->p_next;
+    SLresult r = Enqueue(sys->playerBufferQueue,
+        &sys->buf[unit_size * sys->next_buf], unit_size);
 
-    vlc_mutex_unlock( &p_sys->lock );
-    SLresult r = Enqueue( p_sys->playerBufferQueue, b->p_buffer, b->i_buffer );
-    vlc_mutex_lock( &p_sys->lock );
+    sys->samples -= sys->samples_per_buf;
 
     if (r == SL_RESULT_SUCCESS) {
-        /* Remove that block from the list of audio not yet written */
-        p_sys->buffers++;
-        p_sys->p_buffer_chain = next;
-        if (!p_sys->p_buffer_chain)
-            p_sys->pp_buffer_last = &p_sys->p_buffer_chain;
+        if (++sys->next_buf == OPENSLES_BUFFERS)
+            sys->next_buf = 0;
+        return true;
     } else {
-        /* Remove that block from the list of audio already written */
-        msg_Err( p_aout, "error %lu when writing %d bytes, %d/255 buffers occupied %s",
-                r, b->i_buffer, p_sys->buffers,
+        /* XXX : if writing fails, we don't retry */
+        msg_Err(aout, "error %lu when writing %d bytes %s",
+                r, b->i_buffer,
                 (r == SL_RESULT_BUFFER_INSUFFICIENT) ? " (buffer insufficient)" : "");
-
-        p_sys->pp_last = pp_last_saved;
-        *pp_last_saved = p_last_saved;
-
-        b->p_next = next_saved;
-
-        p_sys->length -= len;
-        next = NULL; /* We'll try again next time */
+        return false;
     }
-
-    return next != NULL;
 }
 
 /*****************************************************************************
  * Play: play a sound
  *****************************************************************************/
-static void Play( audio_output_t *p_aout, block_t *p_buffer )
+static void Play(audio_output_t *aout, block_t *p_buffer)
 {
-    aout_sys_t *p_sys = p_aout->sys;
+    aout_sys_t *sys = aout->sys;
 
     p_buffer->p_next = NULL; /* Make sur our linked list doesn't use old references */
-    vlc_mutex_lock(&p_sys->lock);
-    block_ChainLastAppend( &p_sys->pp_buffer_last, p_buffer );
-    while (WriteBuffer(p_aout))
-        ;
-    vlc_mutex_unlock( &p_sys->lock );
-}
+    vlc_mutex_lock(&sys->lock);
 
-static void PlayedCallback (SLAndroidSimpleBufferQueueItf caller, void *pContext )
-{
-    (void)caller;
-    block_t *p_block;
-    audio_output_t *p_aout = pContext;
-    aout_sys_t *p_sys = p_aout->sys;
-
-    assert (caller == p_sys->playerBufferQueue);
+    sys->samples += p_buffer->i_buffer / bytesPerSample();
 
-    vlc_mutex_lock( &p_sys->lock );
-    p_sys->buffers--;
-    p_sys->last_callback = mdate();
+    /* Hold this block until we can write it into the OpenSL buffer */
+    block_ChainLastAppend(&sys->pp_buffer_last, p_buffer);
 
-    p_block = p_sys->p_chain;
-    assert( p_block );
+    /* Fill OpenSL buffer */
+    while (WriteBuffer(aout))
+        ;
 
-    p_sys->p_chain = p_sys->p_chain->p_next;
-    /* if we exhausted our fifo, we must reset the pointer to the last
-     * appended block */
-    if (!p_sys->p_chain)
-        p_sys->pp_last = &p_sys->p_chain;
+    vlc_mutex_unlock(&sys->lock);
+}
 
-    p_sys->length -= p_block->i_length;
+static void PlayedCallback (SLAndroidSimpleBufferQueueItf caller, void *pContext)
+{
+    (void)caller;
+    audio_output_t *aout = pContext;
+    aout_sys_t *sys = aout->sys;
 
-    vlc_mutex_unlock( &p_sys->lock );
+    assert (caller == sys->playerBufferQueue);
 
-    block_Release( p_block );
+    vlc_mutex_lock(&sys->lock);
+    sys->started = true;
+    vlc_mutex_unlock(&sys->lock);
 }
 /*****************************************************************************
- * Open
+ *
  *****************************************************************************/
-static int Start( audio_output_t *p_aout, audio_sample_format_t *restrict fmt )
+static int Start(audio_output_t *aout, audio_sample_format_t *restrict fmt)
 {
     SLresult       result;
-    SLEngineItf    engineEngine;
-
-    /* Allocate structure */
-    p_aout->sys = calloc( 1, sizeof( aout_sys_t ) );
-    if( unlikely( p_aout->sys == NULL ) )
-        return VLC_ENOMEM;
-
-    aout_sys_t *p_sys = p_aout->sys;
-
-    //Acquiring LibOpenSLES symbols :
-    p_sys->p_so_handle = dlopen( "libOpenSLES.so", RTLD_NOW );
-    if( p_sys->p_so_handle == NULL )
-    {
-        msg_Err( p_aout, "Failed to load libOpenSLES" );
-        goto error;
-    }
-
-    typedef SLresult (*slCreateEngine_t)(
-            SLObjectItf*, SLuint32, const SLEngineOption*, SLuint32,
-            const SLInterfaceID*, const SLboolean* );
-    slCreateEngine_t    slCreateEnginePtr = NULL;
-
-    SLInterfaceID *SL_IID_ENGINE;
-    SLInterfaceID *SL_IID_ANDROIDSIMPLEBUFFERQUEUE;
-    SLInterfaceID *SL_IID_VOLUME;
-    SLInterfaceID *SL_IID_PLAY;
-
-#define OPENSL_DLSYM( dest, handle, name )                   \
-    dest = dlsym( handle, name );                            \
-    if( dest == NULL )                                       \
-    {                                                        \
-        msg_Err( p_aout, "Failed to load symbol %s", name ); \
-        goto error;                                          \
-    }
-
-    OPENSL_DLSYM( slCreateEnginePtr, p_sys->p_so_handle, "slCreateEngine" );
-    OPENSL_DLSYM( SL_IID_ANDROIDSIMPLEBUFFERQUEUE, p_sys->p_so_handle,
-                 "SL_IID_ANDROIDSIMPLEBUFFERQUEUE" );
-    OPENSL_DLSYM( SL_IID_ENGINE, p_sys->p_so_handle, "SL_IID_ENGINE" );
-    OPENSL_DLSYM( SL_IID_PLAY, p_sys->p_so_handle, "SL_IID_PLAY" );
-    OPENSL_DLSYM( SL_IID_VOLUME, p_sys->p_so_handle, "SL_IID_VOLUME" );
-
-
-#define CHECK_OPENSL_ERROR( msg )                   \
-    if( unlikely( result != SL_RESULT_SUCCESS ) )   \
-    {                                               \
-        msg_Err( p_aout, msg" (%lu)", result );     \
-        goto error;                                 \
-    }
-
-    // create engine
-    result = slCreateEnginePtr( &p_sys->engineObject, 0, NULL, 0, NULL, NULL );
-    CHECK_OPENSL_ERROR( "Failed to create engine" );
-
-    // realize the engine in synchronous mode
-    result = Realize( p_sys->engineObject, SL_BOOLEAN_FALSE );
-    CHECK_OPENSL_ERROR( "Failed to realize engine" );
-
-    // get the engine interface, needed to create other objects
-    result = GetInterface( p_sys->engineObject, *SL_IID_ENGINE, &engineEngine );
-    CHECK_OPENSL_ERROR( "Failed to get the engine interface" );
-
-    // create output mix, with environmental reverb specified as a non-required interface
-    const SLInterfaceID ids1[] = { *SL_IID_VOLUME };
-    const SLboolean req1[] = { SL_BOOLEAN_FALSE };
-    result = CreateOutputMix( engineEngine, &p_sys->outputMixObject, 1, ids1, req1 );
-    CHECK_OPENSL_ERROR( "Failed to create output mix" );
-
-    // realize the output mix in synchronous mode
-    result = Realize( p_sys->outputMixObject, SL_BOOLEAN_FALSE );
-    CHECK_OPENSL_ERROR( "Failed to realize output mix" );
 
+    aout_sys_t *sys = aout->sys;
 
     // configure audio source - this defines the number of samples you can enqueue.
     SLDataLocator_AndroidSimpleBufferQueue loc_bufq = {
         SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE,
-        255 // Maximum number of buffers to enqueue.
+        OPENSLES_BUFFERS
     };
 
     SLDataFormat_PCM format_pcm;
@@ -409,89 +378,193 @@ static int Start( audio_output_t *p_aout, audio_sample_format_t *restrict fmt )
     // configure audio sink
     SLDataLocator_OutputMix loc_outmix = {
         SL_DATALOCATOR_OUTPUTMIX,
-        p_sys->outputMixObject
+        sys->outputMixObject
     };
     SLDataSink audioSnk = {&loc_outmix, NULL};
 
     //create audio player
-    const SLInterfaceID ids2[] = { *SL_IID_ANDROIDSIMPLEBUFFERQUEUE, *SL_IID_VOLUME };
+    const SLInterfaceID ids2[] = { sys->SL_IID_ANDROIDSIMPLEBUFFERQUEUE, sys->SL_IID_VOLUME };
     static const SLboolean req2[] = { SL_BOOLEAN_TRUE, SL_BOOLEAN_TRUE };
-    result = CreateAudioPlayer( engineEngine, &p_sys->playerObject, &audioSrc,
-                                    &audioSnk, sizeof( ids2 ) / sizeof( *ids2 ),
-                                    ids2, req2 );
-    CHECK_OPENSL_ERROR( "Failed to create audio player" );
+    result = CreateAudioPlayer(sys->engineEngine, &sys->playerObject, &audioSrc,
+                                    &audioSnk, sizeof(ids2) / sizeof(*ids2),
+                                    ids2, req2);
+    if (unlikely(result != SL_RESULT_SUCCESS)) {
+        /* Try again with a more sensible samplerate */
+        fmt->i_rate = 44100;
+        format_pcm.samplesPerSec = ((SLuint32) 44100 * 1000) ;
+        result = CreateAudioPlayer(sys->engineEngine, &sys->playerObject, &audioSrc,
+                &audioSnk, sizeof(ids2) / sizeof(*ids2),
+                ids2, req2);
+    }
+    CHECK_OPENSL_ERROR("Failed to create audio player");
 
-    result = Realize( p_sys->playerObject, SL_BOOLEAN_FALSE );
-    CHECK_OPENSL_ERROR( "Failed to realize player object." );
+    result = Realize(sys->playerObject, SL_BOOLEAN_FALSE);
+    CHECK_OPENSL_ERROR("Failed to realize player object.");
 
-    result = GetInterface( p_sys->playerObject, *SL_IID_PLAY, &p_sys->playerPlay );
-    CHECK_OPENSL_ERROR( "Failed to get player interface." );
+    result = GetInterface(sys->playerObject, sys->SL_IID_PLAY, &sys->playerPlay);
+    CHECK_OPENSL_ERROR("Failed to get player interface.");
 
-    result = GetInterface( p_sys->playerObject, *SL_IID_VOLUME, &p_sys->volumeItf );
-    CHECK_OPENSL_ERROR( "failed to get volume interface." );
+    result = GetInterface(sys->playerObject, sys->SL_IID_VOLUME, &sys->volumeItf);
+    CHECK_OPENSL_ERROR("failed to get volume interface.");
 
-    result = GetInterface( p_sys->playerObject, *SL_IID_ANDROIDSIMPLEBUFFERQUEUE,
-                                                  &p_sys->playerBufferQueue );
-    CHECK_OPENSL_ERROR( "Failed to get buff queue interface" );
+    result = GetInterface(sys->playerObject, sys->SL_IID_ANDROIDSIMPLEBUFFERQUEUE,
+                                                  &sys->playerBufferQueue);
+    CHECK_OPENSL_ERROR("Failed to get buff queue interface");
 
-    result = RegisterCallback( p_sys->playerBufferQueue, PlayedCallback,
-                                   (void*)p_aout);
-    CHECK_OPENSL_ERROR( "Failed to register buff queue callback." );
+    result = RegisterCallback(sys->playerBufferQueue, PlayedCallback,
+                                   (void*)aout);
+    CHECK_OPENSL_ERROR("Failed to register buff queue callback.");
 
     // set the player's state to playing
-    result = SetPlayState( p_sys->playerPlay, SL_PLAYSTATE_PLAYING );
-    CHECK_OPENSL_ERROR( "Failed to switch to playing state" );
+    result = SetPlayState(sys->playerPlay, SL_PLAYSTATE_PLAYING);
+    CHECK_OPENSL_ERROR("Failed to switch to playing state");
+
+    /* XXX: rounding shouldn't affect us at normal sampling rate */
+    sys->rate = fmt->i_rate;
+    sys->samples_per_buf = OPENSLES_BUFLEN * fmt->i_rate / 1000;
+    sys->buf = malloc(OPENSLES_BUFFERS * sys->samples_per_buf * bytesPerSample());
+    if (!sys->buf)
+        goto error;
 
-    vlc_mutex_init( &p_sys->lock );
-    p_sys->p_chain = NULL;
-    p_sys->pp_last = &p_sys->p_chain;
-    p_sys->p_buffer_chain = NULL;
-    p_sys->pp_buffer_last = &p_sys->p_buffer_chain;
+    sys->started = false;
+    sys->next_buf = 0;
 
-    // we want 16bit signed data little endian.
-    fmt->i_format              = VLC_CODEC_S16L;
-    fmt->i_physical_channels   = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
-    p_aout->play               = Play;
-    p_aout->pause              = Pause;
-    p_aout->flush              = Flush;
-    p_aout->mute_set           = MuteSet;
-    p_aout->volume_set         = VolumeSet;
+    sys->p_buffer_chain = NULL;
+    sys->pp_buffer_last = &sys->p_buffer_chain;
+    sys->samples = 0;
 
-    SetPositionUpdatePeriod( p_sys->playerPlay, AOUT_MIN_PREPARE_TIME * 1000 / CLOCK_FREQ);
+    // we want 16bit signed data native endian.
+    fmt->i_format              = VLC_CODEC_S16N;
+    fmt->i_physical_channels   = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
 
-    aout_FormatPrepare( fmt );
+    SetPositionUpdatePeriod(sys->playerPlay, AOUT_MIN_PREPARE_TIME * 1000 / CLOCK_FREQ);
 
-    p_sys->format = *fmt;
+    aout_FormatPrepare(fmt);
 
     return VLC_SUCCESS;
+
 error:
-    Clean( p_sys );
+    if (sys->playerObject) {
+        Destroy(sys->playerObject);
+        sys->playerObject = NULL;
+    }
+
     return VLC_EGENERIC;
 }
 
+static void Stop(audio_output_t *aout)
+{
+    aout_sys_t *sys = aout->sys;
+
+    SetPlayState(sys->playerPlay, SL_PLAYSTATE_STOPPED);
+    //Flush remaining buffers if any.
+    Clear(sys->playerBufferQueue);
+
+    free(sys->buf);
+    block_ChainRelease(sys->p_buffer_chain);
+
+    Destroy(sys->playerObject);
+    sys->playerObject = NULL;
+}
+
 /*****************************************************************************
- * Close
+ *
  *****************************************************************************/
-static void Stop( audio_output_t *p_aout )
+static void Close(vlc_object_t *obj)
 {
-    aout_sys_t     *p_sys = p_aout->sys;
+    audio_output_t *aout = (audio_output_t *)obj;
+    aout_sys_t *sys = aout->sys;
 
-    SetPlayState( p_sys->playerPlay, SL_PLAYSTATE_STOPPED );
-    //Flush remaining buffers if any.
-    Clear( p_sys->playerBufferQueue );
-    block_ChainRelease( p_sys->p_chain );
-    block_ChainRelease( p_sys->p_buffer_chain);
-    vlc_mutex_destroy( &p_sys->lock );
-    Clean( p_sys );
+    Destroy(sys->outputMixObject);
+    Destroy(sys->engineObject);
+    dlclose(sys->p_so_handle);
+    vlc_mutex_destroy(&sys->lock);
+    free(sys);
 }
 
 static int Open (vlc_object_t *obj)
 {
     audio_output_t *aout = (audio_output_t *)obj;
+    aout_sys_t *sys;
+    SLresult result;
+
+    aout->sys = sys = calloc(1, sizeof(*sys));
+    if (unlikely(sys == NULL))
+        return VLC_ENOMEM;
+
+    sys->p_so_handle = dlopen("libOpenSLES.so", RTLD_NOW);
+    if (sys->p_so_handle == NULL)
+    {
+        msg_Err(aout, "Failed to load libOpenSLES");
+        goto error;
+    }
+
+    sys->slCreateEnginePtr = dlsym(sys->p_so_handle, "slCreateEngine");
+    if (unlikely(sys->slCreateEnginePtr == NULL))
+    {
+        msg_Err(aout, "Failed to load symbol slCreateEngine");
+        goto error;
+    }
+
+#define OPENSL_DLSYM(dest, name)                       \
+    do {                                                       \
+        const SLInterfaceID *sym = dlsym(sys->p_so_handle, "SL_IID_"name);        \
+        if (unlikely(sym == NULL))                             \
+        {                                                      \
+            msg_Err(aout, "Failed to load symbol SL_IID_"name); \
+            goto error;                                        \
+        }                                                      \
+        sys->dest = *sym;                                           \
+    } while(0)
+
+    OPENSL_DLSYM(SL_IID_ANDROIDSIMPLEBUFFERQUEUE, "ANDROIDSIMPLEBUFFERQUEUE");
+    OPENSL_DLSYM(SL_IID_ENGINE, "ENGINE");
+    OPENSL_DLSYM(SL_IID_PLAY, "PLAY");
+    OPENSL_DLSYM(SL_IID_VOLUME, "VOLUME");
+#undef OPENSL_DLSYM
+
+    // create engine
+    result = sys->slCreateEnginePtr(&sys->engineObject, 0, NULL, 0, NULL, NULL);
+    CHECK_OPENSL_ERROR("Failed to create engine");
+
+    // realize the engine in synchronous mode
+    result = Realize(sys->engineObject, SL_BOOLEAN_FALSE);
+    CHECK_OPENSL_ERROR("Failed to realize engine");
+
+    // get the engine interface, needed to create other objects
+    result = GetInterface(sys->engineObject, sys->SL_IID_ENGINE, &sys->engineEngine);
+    CHECK_OPENSL_ERROR("Failed to get the engine interface");
+
+    // create output mix, with environmental reverb specified as a non-required interface
+    const SLInterfaceID ids1[] = { sys->SL_IID_VOLUME };
+    const SLboolean req1[] = { SL_BOOLEAN_FALSE };
+    result = CreateOutputMix(sys->engineEngine, &sys->outputMixObject, 1, ids1, req1);
+    CHECK_OPENSL_ERROR("Failed to create output mix");
+
+    // realize the output mix in synchronous mode
+    result = Realize(sys->outputMixObject, SL_BOOLEAN_FALSE);
+    CHECK_OPENSL_ERROR("Failed to realize output mix");
+
+    vlc_mutex_init(&sys->lock);
+
+    aout->start      = Start;
+    aout->stop       = Stop;
+    aout->time_get   = TimeGet;
+    aout->play       = Play;
+    aout->pause      = Pause;
+    aout->flush      = Flush;
+    aout->mute_set   = MuteSet;
+    aout->volume_set = VolumeSet;
 
-    /* FIXME: set volume/mute here */
-    aout->start = Start;
-    aout->stop = Stop;
-    aout->time_get = TimeGet;
     return VLC_SUCCESS;
+
+error:
+    if (sys->outputMixObject)
+        Destroy(sys->outputMixObject);
+    if (sys->engineObject)
+        Destroy(sys->engineObject);
+    if (sys->p_so_handle)
+        dlclose(sys->p_so_handle);
+    free(sys);
+    return VLC_EGENERIC;
 }