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      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #define LOG_TAG "EffectVisualizer"
     18 //#define LOG_NDEBUG 0
     19 #include <cutils/log.h>
     20 #include <assert.h>
     21 #include <stdlib.h>
     22 #include <string.h>
     23 #include <new>
     24 #include <time.h>
     25 #include <math.h>
     26 #include <audio_effects/effect_visualizer.h>
     27 
     28 
     29 extern "C" {
     30 
     31 // effect_handle_t interface implementation for visualizer effect
     32 extern const struct effect_interface_s gVisualizerInterface;
     33 
     34 // Google Visualizer UUID: d069d9e0-8329-11df-9168-0002a5d5c51b
     35 const effect_descriptor_t gVisualizerDescriptor = {
     36         {0xe46b26a0, 0xdddd, 0x11db, 0x8afd, {0x00, 0x02, 0xa5, 0xd5, 0xc5, 0x1b}}, // type
     37         {0xd069d9e0, 0x8329, 0x11df, 0x9168, {0x00, 0x02, 0xa5, 0xd5, 0xc5, 0x1b}}, // uuid
     38         EFFECT_CONTROL_API_VERSION,
     39         (EFFECT_FLAG_TYPE_INSERT | EFFECT_FLAG_INSERT_FIRST),
     40         0, // TODO
     41         1,
     42         "Visualizer",
     43         "The Android Open Source Project",
     44 };
     45 
     46 enum visualizer_state_e {
     47     VISUALIZER_STATE_UNINITIALIZED,
     48     VISUALIZER_STATE_INITIALIZED,
     49     VISUALIZER_STATE_ACTIVE,
     50 };
     51 
     52 // maximum time since last capture buffer update before resetting capture buffer. This means
     53 // that the framework has stopped playing audio and we must start returning silence
     54 #define MAX_STALL_TIME_MS 1000
     55 
     56 #define CAPTURE_BUF_SIZE 65536 // "64k should be enough for everyone"
     57 
     58 #define DISCARD_MEASUREMENTS_TIME_MS 2000 // discard measurements older than this number of ms
     59 
     60 // maximum number of buffers for which we keep track of the measurements
     61 #define MEASUREMENT_WINDOW_MAX_SIZE_IN_BUFFERS 25 // note: buffer index is stored in uint8_t
     62 
     63 
     64 struct BufferStats {
     65     bool mIsValid;
     66     uint16_t mPeakU16; // the positive peak of the absolute value of the samples in a buffer
     67     float mRmsSquared; // the average square of the samples in a buffer
     68 };
     69 
     70 struct VisualizerContext {
     71     const struct effect_interface_s *mItfe;
     72     effect_config_t mConfig;
     73     uint32_t mCaptureIdx;
     74     uint32_t mCaptureSize;
     75     uint32_t mScalingMode;
     76     uint8_t mState;
     77     uint32_t mLastCaptureIdx;
     78     uint32_t mLatency;
     79     struct timespec mBufferUpdateTime;
     80     uint8_t mCaptureBuf[CAPTURE_BUF_SIZE];
     81     // for measurements
     82     uint8_t mChannelCount; // to avoid recomputing it every time a buffer is processed
     83     uint32_t mMeasurementMode;
     84     uint8_t mMeasurementWindowSizeInBuffers;
     85     uint8_t mMeasurementBufferIdx;
     86     BufferStats mPastMeasurements[MEASUREMENT_WINDOW_MAX_SIZE_IN_BUFFERS];
     87 };
     88 
     89 //
     90 //--- Local functions
     91 //
     92 uint32_t Visualizer_getDeltaTimeMsFromUpdatedTime(VisualizerContext* pContext) {
     93     uint32_t deltaMs = 0;
     94     if (pContext->mBufferUpdateTime.tv_sec != 0) {
     95         struct timespec ts;
     96         if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0) {
     97             time_t secs = ts.tv_sec - pContext->mBufferUpdateTime.tv_sec;
     98             long nsec = ts.tv_nsec - pContext->mBufferUpdateTime.tv_nsec;
     99             if (nsec < 0) {
    100                 --secs;
    101                 nsec += 1000000000;
    102             }
    103             deltaMs = secs * 1000 + nsec / 1000000;
    104         }
    105     }
    106     return deltaMs;
    107 }
    108 
    109 
    110 void Visualizer_reset(VisualizerContext *pContext)
    111 {
    112     pContext->mCaptureIdx = 0;
    113     pContext->mLastCaptureIdx = 0;
    114     pContext->mBufferUpdateTime.tv_sec = 0;
    115     pContext->mLatency = 0;
    116     memset(pContext->mCaptureBuf, 0x80, CAPTURE_BUF_SIZE);
    117 }
    118 
    119 //----------------------------------------------------------------------------
    120 // Visualizer_setConfig()
    121 //----------------------------------------------------------------------------
    122 // Purpose: Set input and output audio configuration.
    123 //
    124 // Inputs:
    125 //  pContext:   effect engine context
    126 //  pConfig:    pointer to effect_config_t structure holding input and output
    127 //      configuration parameters
    128 //
    129 // Outputs:
    130 //
    131 //----------------------------------------------------------------------------
    132 
    133 int Visualizer_setConfig(VisualizerContext *pContext, effect_config_t *pConfig)
    134 {
    135     ALOGV("Visualizer_setConfig start");
    136 
    137     if (pConfig->inputCfg.samplingRate != pConfig->outputCfg.samplingRate) return -EINVAL;
    138     if (pConfig->inputCfg.channels != pConfig->outputCfg.channels) return -EINVAL;
    139     if (pConfig->inputCfg.format != pConfig->outputCfg.format) return -EINVAL;
    140     if (pConfig->inputCfg.channels != AUDIO_CHANNEL_OUT_STEREO) return -EINVAL;
    141     if (pConfig->outputCfg.accessMode != EFFECT_BUFFER_ACCESS_WRITE &&
    142             pConfig->outputCfg.accessMode != EFFECT_BUFFER_ACCESS_ACCUMULATE) return -EINVAL;
    143     if (pConfig->inputCfg.format != AUDIO_FORMAT_PCM_16_BIT) return -EINVAL;
    144 
    145     pContext->mConfig = *pConfig;
    146 
    147     Visualizer_reset(pContext);
    148 
    149     return 0;
    150 }
    151 
    152 
    153 //----------------------------------------------------------------------------
    154 // Visualizer_getConfig()
    155 //----------------------------------------------------------------------------
    156 // Purpose: Get input and output audio configuration.
    157 //
    158 // Inputs:
    159 //  pContext:   effect engine context
    160 //  pConfig:    pointer to effect_config_t structure holding input and output
    161 //      configuration parameters
    162 //
    163 // Outputs:
    164 //
    165 //----------------------------------------------------------------------------
    166 
    167 void Visualizer_getConfig(VisualizerContext *pContext, effect_config_t *pConfig)
    168 {
    169     *pConfig = pContext->mConfig;
    170 }
    171 
    172 
    173 //----------------------------------------------------------------------------
    174 // Visualizer_init()
    175 //----------------------------------------------------------------------------
    176 // Purpose: Initialize engine with default configuration.
    177 //
    178 // Inputs:
    179 //  pContext:   effect engine context
    180 //
    181 // Outputs:
    182 //
    183 //----------------------------------------------------------------------------
    184 
    185 int Visualizer_init(VisualizerContext *pContext)
    186 {
    187     pContext->mConfig.inputCfg.accessMode = EFFECT_BUFFER_ACCESS_READ;
    188     pContext->mConfig.inputCfg.channels = AUDIO_CHANNEL_OUT_STEREO;
    189     pContext->mConfig.inputCfg.format = AUDIO_FORMAT_PCM_16_BIT;
    190     pContext->mConfig.inputCfg.samplingRate = 44100;
    191     pContext->mConfig.inputCfg.bufferProvider.getBuffer = NULL;
    192     pContext->mConfig.inputCfg.bufferProvider.releaseBuffer = NULL;
    193     pContext->mConfig.inputCfg.bufferProvider.cookie = NULL;
    194     pContext->mConfig.inputCfg.mask = EFFECT_CONFIG_ALL;
    195     pContext->mConfig.outputCfg.accessMode = EFFECT_BUFFER_ACCESS_ACCUMULATE;
    196     pContext->mConfig.outputCfg.channels = AUDIO_CHANNEL_OUT_STEREO;
    197     pContext->mConfig.outputCfg.format = AUDIO_FORMAT_PCM_16_BIT;
    198     pContext->mConfig.outputCfg.samplingRate = 44100;
    199     pContext->mConfig.outputCfg.bufferProvider.getBuffer = NULL;
    200     pContext->mConfig.outputCfg.bufferProvider.releaseBuffer = NULL;
    201     pContext->mConfig.outputCfg.bufferProvider.cookie = NULL;
    202     pContext->mConfig.outputCfg.mask = EFFECT_CONFIG_ALL;
    203 
    204     // visualization initialization
    205     pContext->mCaptureSize = VISUALIZER_CAPTURE_SIZE_MAX;
    206     pContext->mScalingMode = VISUALIZER_SCALING_MODE_NORMALIZED;
    207 
    208     // measurement initialization
    209     pContext->mChannelCount = popcount(pContext->mConfig.inputCfg.channels);
    210     pContext->mMeasurementMode = MEASUREMENT_MODE_NONE;
    211     pContext->mMeasurementWindowSizeInBuffers = MEASUREMENT_WINDOW_MAX_SIZE_IN_BUFFERS;
    212     pContext->mMeasurementBufferIdx = 0;
    213     for (uint32_t i=0 ; i<pContext->mMeasurementWindowSizeInBuffers ; i++) {
    214         pContext->mPastMeasurements[i].mIsValid = false;
    215         pContext->mPastMeasurements[i].mPeakU16 = 0;
    216         pContext->mPastMeasurements[i].mRmsSquared = 0;
    217     }
    218 
    219     Visualizer_setConfig(pContext, &pContext->mConfig);
    220 
    221     return 0;
    222 }
    223 
    224 //
    225 //--- Effect Library Interface Implementation
    226 //
    227 
    228 int VisualizerLib_Create(const effect_uuid_t *uuid,
    229                          int32_t sessionId,
    230                          int32_t ioId,
    231                          effect_handle_t *pHandle) {
    232     int ret;
    233     int i;
    234 
    235     if (pHandle == NULL || uuid == NULL) {
    236         return -EINVAL;
    237     }
    238 
    239     if (memcmp(uuid, &gVisualizerDescriptor.uuid, sizeof(effect_uuid_t)) != 0) {
    240         return -EINVAL;
    241     }
    242 
    243     VisualizerContext *pContext = new VisualizerContext;
    244 
    245     pContext->mItfe = &gVisualizerInterface;
    246     pContext->mState = VISUALIZER_STATE_UNINITIALIZED;
    247 
    248     ret = Visualizer_init(pContext);
    249     if (ret < 0) {
    250         ALOGW("VisualizerLib_Create() init failed");
    251         delete pContext;
    252         return ret;
    253     }
    254 
    255     *pHandle = (effect_handle_t)pContext;
    256 
    257     pContext->mState = VISUALIZER_STATE_INITIALIZED;
    258 
    259     ALOGV("VisualizerLib_Create %p", pContext);
    260 
    261     return 0;
    262 
    263 }
    264 
    265 int VisualizerLib_Release(effect_handle_t handle) {
    266     VisualizerContext * pContext = (VisualizerContext *)handle;
    267 
    268     ALOGV("VisualizerLib_Release %p", handle);
    269     if (pContext == NULL) {
    270         return -EINVAL;
    271     }
    272     pContext->mState = VISUALIZER_STATE_UNINITIALIZED;
    273     delete pContext;
    274 
    275     return 0;
    276 }
    277 
    278 int VisualizerLib_GetDescriptor(const effect_uuid_t *uuid,
    279                                 effect_descriptor_t *pDescriptor) {
    280 
    281     if (pDescriptor == NULL || uuid == NULL){
    282         ALOGV("VisualizerLib_GetDescriptor() called with NULL pointer");
    283         return -EINVAL;
    284     }
    285 
    286     if (memcmp(uuid, &gVisualizerDescriptor.uuid, sizeof(effect_uuid_t)) == 0) {
    287         *pDescriptor = gVisualizerDescriptor;
    288         return 0;
    289     }
    290 
    291     return  -EINVAL;
    292 } /* end VisualizerLib_GetDescriptor */
    293 
    294 //
    295 //--- Effect Control Interface Implementation
    296 //
    297 
    298 static inline int16_t clamp16(int32_t sample)
    299 {
    300     if ((sample>>15) ^ (sample>>31))
    301         sample = 0x7FFF ^ (sample>>31);
    302     return sample;
    303 }
    304 
    305 int Visualizer_process(
    306         effect_handle_t self,audio_buffer_t *inBuffer, audio_buffer_t *outBuffer)
    307 {
    308     VisualizerContext * pContext = (VisualizerContext *)self;
    309 
    310     if (pContext == NULL) {
    311         return -EINVAL;
    312     }
    313 
    314     if (inBuffer == NULL || inBuffer->raw == NULL ||
    315         outBuffer == NULL || outBuffer->raw == NULL ||
    316         inBuffer->frameCount != outBuffer->frameCount ||
    317         inBuffer->frameCount == 0) {
    318         return -EINVAL;
    319     }
    320 
    321     // perform measurements if needed
    322     if (pContext->mMeasurementMode & MEASUREMENT_MODE_PEAK_RMS) {
    323         // find the peak and RMS squared for the new buffer
    324         uint32_t inIdx;
    325         int16_t maxSample = 0;
    326         float rmsSqAcc = 0;
    327         for (inIdx = 0 ; inIdx < inBuffer->frameCount * pContext->mChannelCount ; inIdx++) {
    328             if (inBuffer->s16[inIdx] > maxSample) {
    329                 maxSample = inBuffer->s16[inIdx];
    330             } else if (-inBuffer->s16[inIdx] > maxSample) {
    331                 maxSample = -inBuffer->s16[inIdx];
    332             }
    333             rmsSqAcc += (inBuffer->s16[inIdx] * inBuffer->s16[inIdx]);
    334         }
    335         // store the measurement
    336         pContext->mPastMeasurements[pContext->mMeasurementBufferIdx].mPeakU16 = (uint16_t)maxSample;
    337         pContext->mPastMeasurements[pContext->mMeasurementBufferIdx].mRmsSquared =
    338                 rmsSqAcc / (inBuffer->frameCount * pContext->mChannelCount);
    339         pContext->mPastMeasurements[pContext->mMeasurementBufferIdx].mIsValid = true;
    340         if (++pContext->mMeasurementBufferIdx >= pContext->mMeasurementWindowSizeInBuffers) {
    341             pContext->mMeasurementBufferIdx = 0;
    342         }
    343     }
    344 
    345     // all code below assumes stereo 16 bit PCM output and input
    346     int32_t shift;
    347 
    348     if (pContext->mScalingMode == VISUALIZER_SCALING_MODE_NORMALIZED) {
    349         // derive capture scaling factor from peak value in current buffer
    350         // this gives more interesting captures for display.
    351         shift = 32;
    352         int len = inBuffer->frameCount * 2;
    353         for (int i = 0; i < len; i++) {
    354             int32_t smp = inBuffer->s16[i];
    355             if (smp < 0) smp = -smp - 1; // take care to keep the max negative in range
    356             int32_t clz = __builtin_clz(smp);
    357             if (shift > clz) shift = clz;
    358         }
    359         // A maximum amplitude signal will have 17 leading zeros, which we want to
    360         // translate to a shift of 8 (for converting 16 bit to 8 bit)
    361         shift = 25 - shift;
    362         // Never scale by less than 8 to avoid returning unaltered PCM signal.
    363         if (shift < 3) {
    364             shift = 3;
    365         }
    366         // add one to combine the division by 2 needed after summing left and right channels below
    367         shift++;
    368     } else {
    369         assert(pContext->mScalingMode == VISUALIZER_SCALING_MODE_AS_PLAYED);
    370         shift = 9;
    371     }
    372 
    373     uint32_t captIdx;
    374     uint32_t inIdx;
    375     uint8_t *buf = pContext->mCaptureBuf;
    376     for (inIdx = 0, captIdx = pContext->mCaptureIdx;
    377          inIdx < inBuffer->frameCount;
    378          inIdx++, captIdx++) {
    379         if (captIdx >= CAPTURE_BUF_SIZE) {
    380             // wrap around
    381             captIdx = 0;
    382         }
    383         int32_t smp = inBuffer->s16[2 * inIdx] + inBuffer->s16[2 * inIdx + 1];
    384         smp = smp >> shift;
    385         buf[captIdx] = ((uint8_t)smp)^0x80;
    386     }
    387 
    388     // XXX the following two should really be atomic, though it probably doesn't
    389     // matter much for visualization purposes
    390     pContext->mCaptureIdx = captIdx;
    391     // update last buffer update time stamp
    392     if (clock_gettime(CLOCK_MONOTONIC, &pContext->mBufferUpdateTime) < 0) {
    393         pContext->mBufferUpdateTime.tv_sec = 0;
    394     }
    395 
    396     if (inBuffer->raw != outBuffer->raw) {
    397         if (pContext->mConfig.outputCfg.accessMode == EFFECT_BUFFER_ACCESS_ACCUMULATE) {
    398             for (size_t i = 0; i < outBuffer->frameCount*2; i++) {
    399                 outBuffer->s16[i] = clamp16(outBuffer->s16[i] + inBuffer->s16[i]);
    400             }
    401         } else {
    402             memcpy(outBuffer->raw, inBuffer->raw, outBuffer->frameCount * 2 * sizeof(int16_t));
    403         }
    404     }
    405     if (pContext->mState != VISUALIZER_STATE_ACTIVE) {
    406         return -ENODATA;
    407     }
    408     return 0;
    409 }   // end Visualizer_process
    410 
    411 int Visualizer_command(effect_handle_t self, uint32_t cmdCode, uint32_t cmdSize,
    412         void *pCmdData, uint32_t *replySize, void *pReplyData) {
    413 
    414     VisualizerContext * pContext = (VisualizerContext *)self;
    415     int retsize;
    416 
    417     if (pContext == NULL || pContext->mState == VISUALIZER_STATE_UNINITIALIZED) {
    418         return -EINVAL;
    419     }
    420 
    421 //    ALOGV("Visualizer_command command %d cmdSize %d",cmdCode, cmdSize);
    422 
    423     switch (cmdCode) {
    424     case EFFECT_CMD_INIT:
    425         if (pReplyData == NULL || *replySize != sizeof(int)) {
    426             return -EINVAL;
    427         }
    428         *(int *) pReplyData = Visualizer_init(pContext);
    429         break;
    430     case EFFECT_CMD_SET_CONFIG:
    431         if (pCmdData == NULL || cmdSize != sizeof(effect_config_t)
    432                 || pReplyData == NULL || *replySize != sizeof(int)) {
    433             return -EINVAL;
    434         }
    435         *(int *) pReplyData = Visualizer_setConfig(pContext,
    436                 (effect_config_t *) pCmdData);
    437         break;
    438     case EFFECT_CMD_GET_CONFIG:
    439         if (pReplyData == NULL ||
    440             *replySize != sizeof(effect_config_t)) {
    441             return -EINVAL;
    442         }
    443         Visualizer_getConfig(pContext, (effect_config_t *)pReplyData);
    444         break;
    445     case EFFECT_CMD_RESET:
    446         Visualizer_reset(pContext);
    447         break;
    448     case EFFECT_CMD_ENABLE:
    449         if (pReplyData == NULL || *replySize != sizeof(int)) {
    450             return -EINVAL;
    451         }
    452         if (pContext->mState != VISUALIZER_STATE_INITIALIZED) {
    453             return -ENOSYS;
    454         }
    455         pContext->mState = VISUALIZER_STATE_ACTIVE;
    456         ALOGV("EFFECT_CMD_ENABLE() OK");
    457         *(int *)pReplyData = 0;
    458         break;
    459     case EFFECT_CMD_DISABLE:
    460         if (pReplyData == NULL || *replySize != sizeof(int)) {
    461             return -EINVAL;
    462         }
    463         if (pContext->mState != VISUALIZER_STATE_ACTIVE) {
    464             return -ENOSYS;
    465         }
    466         pContext->mState = VISUALIZER_STATE_INITIALIZED;
    467         ALOGV("EFFECT_CMD_DISABLE() OK");
    468         *(int *)pReplyData = 0;
    469         break;
    470     case EFFECT_CMD_GET_PARAM: {
    471         if (pCmdData == NULL ||
    472             cmdSize != (int)(sizeof(effect_param_t) + sizeof(uint32_t)) ||
    473             pReplyData == NULL ||
    474             *replySize < (int)(sizeof(effect_param_t) + sizeof(uint32_t) + sizeof(uint32_t))) {
    475             return -EINVAL;
    476         }
    477         memcpy(pReplyData, pCmdData, sizeof(effect_param_t) + sizeof(uint32_t));
    478         effect_param_t *p = (effect_param_t *)pReplyData;
    479         p->status = 0;
    480         *replySize = sizeof(effect_param_t) + sizeof(uint32_t);
    481         if (p->psize != sizeof(uint32_t)) {
    482             p->status = -EINVAL;
    483             break;
    484         }
    485         switch (*(uint32_t *)p->data) {
    486         case VISUALIZER_PARAM_CAPTURE_SIZE:
    487             ALOGV("get mCaptureSize = %d", pContext->mCaptureSize);
    488             *((uint32_t *)p->data + 1) = pContext->mCaptureSize;
    489             p->vsize = sizeof(uint32_t);
    490             *replySize += sizeof(uint32_t);
    491             break;
    492         case VISUALIZER_PARAM_SCALING_MODE:
    493             ALOGV("get mScalingMode = %d", pContext->mScalingMode);
    494             *((uint32_t *)p->data + 1) = pContext->mScalingMode;
    495             p->vsize = sizeof(uint32_t);
    496             *replySize += sizeof(uint32_t);
    497             break;
    498         case VISUALIZER_PARAM_MEASUREMENT_MODE:
    499             ALOGV("get mMeasurementMode = %d", pContext->mMeasurementMode);
    500             *((uint32_t *)p->data + 1) = pContext->mMeasurementMode;
    501             p->vsize = sizeof(uint32_t);
    502             *replySize += sizeof(uint32_t);
    503             break;
    504         default:
    505             p->status = -EINVAL;
    506         }
    507         } break;
    508     case EFFECT_CMD_SET_PARAM: {
    509         if (pCmdData == NULL ||
    510             cmdSize != (int)(sizeof(effect_param_t) + sizeof(uint32_t) + sizeof(uint32_t)) ||
    511             pReplyData == NULL || *replySize != sizeof(int32_t)) {
    512             return -EINVAL;
    513         }
    514         *(int32_t *)pReplyData = 0;
    515         effect_param_t *p = (effect_param_t *)pCmdData;
    516         if (p->psize != sizeof(uint32_t) || p->vsize != sizeof(uint32_t)) {
    517             *(int32_t *)pReplyData = -EINVAL;
    518             break;
    519         }
    520         switch (*(uint32_t *)p->data) {
    521         case VISUALIZER_PARAM_CAPTURE_SIZE:
    522             pContext->mCaptureSize = *((uint32_t *)p->data + 1);
    523             ALOGV("set mCaptureSize = %d", pContext->mCaptureSize);
    524             break;
    525         case VISUALIZER_PARAM_SCALING_MODE:
    526             pContext->mScalingMode = *((uint32_t *)p->data + 1);
    527             ALOGV("set mScalingMode = %d", pContext->mScalingMode);
    528             break;
    529         case VISUALIZER_PARAM_LATENCY:
    530             pContext->mLatency = *((uint32_t *)p->data + 1);
    531             ALOGV("set mLatency = %d", pContext->mLatency);
    532             break;
    533         case VISUALIZER_PARAM_MEASUREMENT_MODE:
    534             pContext->mMeasurementMode = *((uint32_t *)p->data + 1);
    535             ALOGV("set mMeasurementMode = %d", pContext->mMeasurementMode);
    536             break;
    537         default:
    538             *(int32_t *)pReplyData = -EINVAL;
    539         }
    540         } break;
    541     case EFFECT_CMD_SET_DEVICE:
    542     case EFFECT_CMD_SET_VOLUME:
    543     case EFFECT_CMD_SET_AUDIO_MODE:
    544         break;
    545 
    546 
    547     case VISUALIZER_CMD_CAPTURE:
    548         if (pReplyData == NULL || *replySize != pContext->mCaptureSize) {
    549             ALOGV("VISUALIZER_CMD_CAPTURE() error *replySize %d pContext->mCaptureSize %d",
    550                     *replySize, pContext->mCaptureSize);
    551             return -EINVAL;
    552         }
    553         if (pContext->mState == VISUALIZER_STATE_ACTIVE) {
    554             int32_t latencyMs = pContext->mLatency;
    555             const uint32_t deltaMs = Visualizer_getDeltaTimeMsFromUpdatedTime(pContext);
    556             latencyMs -= deltaMs;
    557             if (latencyMs < 0) {
    558                 latencyMs = 0;
    559             }
    560             const uint32_t deltaSmpl = pContext->mConfig.inputCfg.samplingRate * latencyMs / 1000;
    561 
    562             int32_t capturePoint = pContext->mCaptureIdx - pContext->mCaptureSize - deltaSmpl;
    563             int32_t captureSize = pContext->mCaptureSize;
    564             if (capturePoint < 0) {
    565                 int32_t size = -capturePoint;
    566                 if (size > captureSize) {
    567                     size = captureSize;
    568                 }
    569                 memcpy(pReplyData,
    570                        pContext->mCaptureBuf + CAPTURE_BUF_SIZE + capturePoint,
    571                        size);
    572                 pReplyData = (char *)pReplyData + size;
    573                 captureSize -= size;
    574                 capturePoint = 0;
    575             }
    576             memcpy(pReplyData,
    577                    pContext->mCaptureBuf + capturePoint,
    578                    captureSize);
    579 
    580 
    581             // if audio framework has stopped playing audio although the effect is still
    582             // active we must clear the capture buffer to return silence
    583             if ((pContext->mLastCaptureIdx == pContext->mCaptureIdx) &&
    584                     (pContext->mBufferUpdateTime.tv_sec != 0)) {
    585                 if (deltaMs > MAX_STALL_TIME_MS) {
    586                     ALOGV("capture going to idle");
    587                     pContext->mBufferUpdateTime.tv_sec = 0;
    588                     memset(pReplyData, 0x80, pContext->mCaptureSize);
    589                 }
    590             }
    591             pContext->mLastCaptureIdx = pContext->mCaptureIdx;
    592         } else {
    593             memset(pReplyData, 0x80, pContext->mCaptureSize);
    594         }
    595 
    596         break;
    597 
    598     case VISUALIZER_CMD_MEASURE: {
    599         uint16_t peakU16 = 0;
    600         float sumRmsSquared = 0.0f;
    601         uint8_t nbValidMeasurements = 0;
    602         // reset measurements if last measurement was too long ago (which implies stored
    603         // measurements aren't relevant anymore and shouldn't bias the new one)
    604         const int32_t delayMs = Visualizer_getDeltaTimeMsFromUpdatedTime(pContext);
    605         if (delayMs > DISCARD_MEASUREMENTS_TIME_MS) {
    606             ALOGV("Discarding measurements, last measurement is %dms old", delayMs);
    607             for (uint32_t i=0 ; i<pContext->mMeasurementWindowSizeInBuffers ; i++) {
    608                 pContext->mPastMeasurements[i].mIsValid = false;
    609                 pContext->mPastMeasurements[i].mPeakU16 = 0;
    610                 pContext->mPastMeasurements[i].mRmsSquared = 0;
    611             }
    612             pContext->mMeasurementBufferIdx = 0;
    613         } else {
    614             // only use actual measurements, otherwise the first RMS measure happening before
    615             // MEASUREMENT_WINDOW_MAX_SIZE_IN_BUFFERS have been played will always be artificially
    616             // low
    617             for (uint32_t i=0 ; i < pContext->mMeasurementWindowSizeInBuffers ; i++) {
    618                 if (pContext->mPastMeasurements[i].mIsValid) {
    619                     if (pContext->mPastMeasurements[i].mPeakU16 > peakU16) {
    620                         peakU16 = pContext->mPastMeasurements[i].mPeakU16;
    621                     }
    622                     sumRmsSquared += pContext->mPastMeasurements[i].mRmsSquared;
    623                     nbValidMeasurements++;
    624                 }
    625             }
    626         }
    627         float rms = nbValidMeasurements == 0 ? 0.0f : sqrtf(sumRmsSquared / nbValidMeasurements);
    628         int32_t* pIntReplyData = (int32_t*)pReplyData;
    629         // convert from I16 sample values to mB and write results
    630         if (rms < 0.000016f) {
    631             pIntReplyData[MEASUREMENT_IDX_RMS] = -9600; //-96dB
    632         } else {
    633             pIntReplyData[MEASUREMENT_IDX_RMS] = (int32_t) (2000 * log10(rms / 32767.0f));
    634         }
    635         if (peakU16 == 0) {
    636             pIntReplyData[MEASUREMENT_IDX_PEAK] = -9600; //-96dB
    637         } else {
    638             pIntReplyData[MEASUREMENT_IDX_PEAK] = (int32_t) (2000 * log10(peakU16 / 32767.0f));
    639         }
    640         ALOGV("VISUALIZER_CMD_MEASURE peak=%d (%dmB), rms=%.1f (%dmB)",
    641                 peakU16, pIntReplyData[MEASUREMENT_IDX_PEAK],
    642                 rms, pIntReplyData[MEASUREMENT_IDX_RMS]);
    643         }
    644         break;
    645 
    646     default:
    647         ALOGW("Visualizer_command invalid command %d",cmdCode);
    648         return -EINVAL;
    649     }
    650 
    651     return 0;
    652 }
    653 
    654 /* Effect Control Interface Implementation: get_descriptor */
    655 int Visualizer_getDescriptor(effect_handle_t   self,
    656                                     effect_descriptor_t *pDescriptor)
    657 {
    658     VisualizerContext * pContext = (VisualizerContext *) self;
    659 
    660     if (pContext == NULL || pDescriptor == NULL) {
    661         ALOGV("Visualizer_getDescriptor() invalid param");
    662         return -EINVAL;
    663     }
    664 
    665     *pDescriptor = gVisualizerDescriptor;
    666 
    667     return 0;
    668 }   /* end Visualizer_getDescriptor */
    669 
    670 // effect_handle_t interface implementation for visualizer effect
    671 const struct effect_interface_s gVisualizerInterface = {
    672         Visualizer_process,
    673         Visualizer_command,
    674         Visualizer_getDescriptor,
    675         NULL,
    676 };
    677 
    678 // This is the only symbol that needs to be exported
    679 __attribute__ ((visibility ("default")))
    680 audio_effect_library_t AUDIO_EFFECT_LIBRARY_INFO_SYM = {
    681     tag : AUDIO_EFFECT_LIBRARY_TAG,
    682     version : EFFECT_LIBRARY_API_VERSION,
    683     name : "Visualizer Library",
    684     implementor : "The Android Open Source Project",
    685     create_effect : VisualizerLib_Create,
    686     release_effect : VisualizerLib_Release,
    687     get_descriptor : VisualizerLib_GetDescriptor,
    688 };
    689 
    690 }; // extern "C"
    691