AAC Decoder: introduce time domain limiter

Introduce time domain limiter. The module is per default enabled for all
  AAC-LC and HE-AAC v1/2 streams. For all ER-AAC-LD and ER-AAC-ELD streams
  the limiter is disabled per default. The feature can be en- or disabled
  via dynamic API parameter. Note that the limiter introduces an additional
  output delay which depends on the module parameters and the streams
  sampling rate.

Bug 9428126

Change-Id: I299a072340b33e2c324facbd347a72c8de3d380e

libAACdec/include/aacdecoder_lib.h

@@ -436,6 +436,16 @@ typedef enum
                                                           2: Create a dual mono output signal from channel 2. \n
                                                           3: Create a dual mono output signal by mixing both channels (L' = R' = 0.5*Ch1 + 0.5*Ch2). */
   AAC_PCM_OUTPUT_CHANNEL_MAPPING          = 0x0003,  /*!< Output buffer channel ordering. 0: MPEG PCE style order, 1: WAV file channel order (default). */
+  AAC_PCM_LIMITER_ENABLE                  = 0x0004,  /*!< Enable signal level limiting. \n
+                                                          -1: Auto-config. Enable limiter for all non-lowdelay configurations by default. \n
+                                                           0: Disable limiter in general. \n
+                                                           1: Enable limiter always.
+                                                          It is recommended to call the decoder with a AACDEC_CLRHIST flag to reset all states when
+                                                          the limiter switch is changed explicitly. */
+  AAC_PCM_LIMITER_ATTACK_TIME             = 0x0005,  /*!< Signal level limiting attack time in ms.
+                                                          Default confguration is 15 ms. Adjustable range from 1 ms to 15 ms. */
+  AAC_PCM_LIMITER_RELEAS_TIME             = 0x0006,  /*!< Signal level limiting release time in ms.
+                                                          Default configuration is 50 ms. Adjustable time must be larger than 0 ms. */
   AAC_PCM_MIN_OUTPUT_CHANNELS             = 0x0011,  /*!< Minimum number of PCM output channels. If higher than the number of encoded audio channels,
                                                           a simple channel extension is applied. \n
                                                           -1, 0: Disable channel extenstion feature. The decoder output contains the same number of

libAACdec/src/aacdec_drc.cpp

@@ -130,7 +130,6 @@ void aacDecoder_drcInit (
   /* init control fields */
   self->enable = 0;
   self->numThreads = 0;
-  self->digitalNorm = 0;
 
   /* init params */
   pParams = &self->params;
@@ -139,8 +138,9 @@ void aacDecoder_drcInit (
   pParams->usrCut   = FL2FXCONST_DBL(0.0f);
   pParams->boost    = FL2FXCONST_DBL(0.0f);
   pParams->usrBoost = FL2FXCONST_DBL(0.0f);
-  pParams->targetRefLevel = AACDEC_DRC_DEFAULT_REF_LEVEL;
+  pParams->targetRefLevel = -1;
   pParams->expiryFrame = AACDEC_DRC_DFLT_EXPIRY_FRAMES;
+  pParams->applyDigitalNorm = 0;
   pParams->applyHeavyCompression = 0;
 
   /* initial program ref level = target ref level */
@@ -222,11 +222,12 @@ AAC_DECODER_ERROR aacDecoder_drcSetParam (
       return AAC_DEC_INVALID_HANDLE;
     }
     if (value < 0) {
-      self->digitalNorm = 0;
+      self->params.applyDigitalNorm = 0;
+      self->params.targetRefLevel = -1;
     }
     else {
       /* ref_level must be between 0 and MAX_REFERENCE_LEVEL, inclusive */
-      self->digitalNorm    = 1;
+      self->params.applyDigitalNorm = 1;
       if (self->params.targetRefLevel != (SCHAR)value) {
         self->params.targetRefLevel = (SCHAR)value;
         self->progRefLevel = (SCHAR)value;  /* Always set the program reference level equal to the
@@ -234,6 +235,16 @@ AAC_DECODER_ERROR aacDecoder_drcSetParam (
       }
     }
     break;
+  case APPLY_NORMALIZATION:
+    if (value < 0 || value > 1) {
+      return AAC_DEC_SET_PARAM_FAIL;
+    }
+    if (self == NULL) {
+      return AAC_DEC_INVALID_HANDLE;
+    }
+    /* Store new parameter value */
+    self->params.applyDigitalNorm = (UCHAR)value;
+    break;
   case APPLY_HEAVY_COMPRESSION:
     if (value < 0 || value > 1) {
       return AAC_DEC_SET_PARAM_FAIL;
@@ -278,7 +289,7 @@ AAC_DECODER_ERROR aacDecoder_drcSetParam (
   self->enable = ( (self->params.boost > (FIXP_DBL)0)
                 || (self->params.cut   > (FIXP_DBL)0)
                 || (self->params.applyHeavyCompression != 0)
-                || (self->digitalNorm == 1) );
+                || (self->params.targetRefLevel >= 0) );
 
 
   return ErrorStatus;
@@ -827,6 +838,7 @@ void aacDecoder_drcApply (
         void                   *pSbrDec,
         CAacDecoderChannelInfo *pAacDecoderChannelInfo,
         CDrcChannelData        *pDrcChData,
+        FIXP_DBL               *extGain,
         int  ch,   /* needed only for SBR */
         int  aacFrameSize,
         int  bSbrPresent )
@@ -838,8 +850,8 @@ void aacDecoder_drcApply (
   FIXP_DBL max_mantissa;
   INT max_exponent;
 
-  FIXP_DBL norm_mantissa = FL2FXCONST_DBL(0.0f);
-  INT  norm_exponent = 0;
+  FIXP_DBL norm_mantissa = FL2FXCONST_DBL(0.5f);
+  INT  norm_exponent = 1;
 
   FIXP_DBL fact_mantissa[MAX_DRC_BANDS];
   INT  fact_exponent[MAX_DRC_BANDS];
@@ -861,6 +873,15 @@ void aacDecoder_drcApply (
 
   if (!self->enable) {
     sbrDecoder_drcDisable( (HANDLE_SBRDECODER)pSbrDec, ch );
+    if (extGain != NULL) {
+      INT gainScale = (INT)*extGain;
+      /* The gain scaling must be passed to the function in the buffer pointed on by extGain. */
+      if (gainScale >= 0 && gainScale <= DFRACT_BITS) {
+        *extGain = scaleValue(norm_mantissa, norm_exponent-gainScale);
+      } else {
+        FDK_ASSERT(0);
+      }
+    }
     return;
   }
 
@@ -876,7 +897,7 @@ void aacDecoder_drcApply (
   reduced DAC SNR (if signal is attenuated) or clipping (if signal is
   boosted) */
 
-  if (self->digitalNorm == 1)
+  if (pParams->targetRefLevel >= 0)
   {
     /* 0.5^((targetRefLevel - progRefLevel)/24) */
     norm_mantissa = fLdPow(
@@ -886,7 +907,18 @@ void aacDecoder_drcApply (
             3,
            &norm_exponent );
   }
-  else {
+  /* Always export the normalization gain (if possible). */
+  if (extGain != NULL) {
+    INT gainScale = (INT)*extGain;
+    /* The gain scaling must be passed to the function in the buffer pointed on by extGain. */
+    if (gainScale >= 0 && gainScale <= DFRACT_BITS) {
+      *extGain = scaleValue(norm_mantissa, norm_exponent-gainScale);
+    } else {
+      FDK_ASSERT(0);
+    }
+  }
+  if (self->params.applyDigitalNorm == 0) {
+    /* Reset normalization gain since this module must not apply it */
     norm_mantissa = FL2FXCONST_DBL(0.5f);
     norm_exponent = 1;
   }

libAACdec/src/aacdec_drc.h

@@ -98,7 +98,6 @@ amm-info@iis.fraunhofer.de
 #include "channel.h"
 #include "FDK_bitstream.h"
 
-#define AACDEC_DRC_DEFAULT_REF_LEVEL  ( 108 )   /* -27 dB below full scale (typical for movies) */
 #define AACDEC_DRC_DFLT_EXPIRY_FRAMES (  50 )   /* Default DRC data expiry time in AAC frames   */
 
 /**
@@ -111,6 +110,7 @@ typedef enum
   TARGET_REF_LEVEL,
   DRC_BS_DELAY,
   DRC_DATA_EXPIRY_FRAME,
+  APPLY_NORMALIZATION,
   APPLY_HEAVY_COMPRESSION
 
 } AACDEC_DRC_PARAM;
@@ -149,6 +149,8 @@ int aacDecoder_drcProlog (
  * \param pSbrDec pointer to SBR decoder instance
  * \param pAacDecoderChannelInfo AAC decoder channel instance to be processed
  * \param pDrcDat DRC channel data
+ * \param extGain Pointer to a FIXP_DBL where a externally applyable gain will be stored into (independently on whether it will be apply internally or not).
+ *                At function call the buffer must hold the scale (0 >= scale < DFRACT_BITS) to be applied on the gain value.
  * \param ch channel index
  * \param aacFrameSize AAC frame size
  * \param bSbrPresent flag indicating that SBR is present, in which case DRC is handed over to the SBR instance pSbrDec
@@ -158,6 +160,7 @@ void aacDecoder_drcApply (
         void                   *pSbrDec,
         CAacDecoderChannelInfo *pAacDecoderChannelInfo,
         CDrcChannelData        *pDrcDat,
+        FIXP_DBL               *extGain,
         int  ch,
         int  aacFrameSize,
         int  bSbrPresent );

libAACdec/src/aacdec_drc_types.h

@@ -140,6 +140,7 @@ typedef struct
   UINT   expiryFrame;
   SCHAR  targetRefLevel;
   UCHAR  bsDelayEnable;
+  UCHAR  applyDigitalNorm;
   UCHAR  applyHeavyCompression;
 
 } CDrcParams;

libAACdec/src/aacdecoder.cpp

@@ -1653,6 +1653,8 @@ LINKSPEC_CPP AAC_DECODER_ERROR CAacDecoder_DecodeFrame(
   {
     int stride, offset, c;
 
+    /* Turn on/off DRC modules level normalization in digital domain depending on the limiter status. */
+    aacDecoder_drcSetParam( self->hDrcInfo, APPLY_NORMALIZATION, (self->limiterEnableCurr) ? 0 : 1 );
     /* Extract DRC control data and map it to channels (without bitstream delay) */
     aacDecoder_drcProlog (
             self->hDrcInfo,
@@ -1703,12 +1705,15 @@ LINKSPEC_CPP AAC_DECODER_ERROR CAacDecoder_DecodeFrame(
         /* Reset DRC control data for this channel */
         aacDecoder_drcInitChannelData ( &self->pAacDecoderStaticChannelInfo[c]->drcData );
       }
+      /* The DRC module demands to be called with the gain field holding the gain scale. */
+      self->extGain[0] = (FIXP_DBL)TDL_GAIN_SCALING;
       /* DRC processing */
       aacDecoder_drcApply (
               self->hDrcInfo,
               self->hSbrDecoder,
               pAacDecoderChannelInfo,
              &self->pAacDecoderStaticChannelInfo[c]->drcData,
+              self->extGain,
               c,
               self->streamInfo.aacSamplesPerFrame,
               self->sbrEnabled
@@ -1726,6 +1731,7 @@ LINKSPEC_CPP AAC_DECODER_ERROR CAacDecoder_DecodeFrame(
                   (self->frameOK && !(flags&AACDEC_CONCEAL)),
                   self->aacCommonData.workBufferCore1->mdctOutTemp
                   );
+          self->extGainDelay = self->streamInfo.aacSamplesPerFrame;
           break;
         case AACDEC_RENDER_ELDFB:
           CBlock_FrequencyToTimeLowDelay(
@@ -1735,6 +1741,7 @@ LINKSPEC_CPP AAC_DECODER_ERROR CAacDecoder_DecodeFrame(
                   self->streamInfo.aacSamplesPerFrame,
                   stride
                   );
+          self->extGainDelay = (self->streamInfo.aacSamplesPerFrame*2 -  self->streamInfo.aacSamplesPerFrame/2 - 1)/2;
           break;
         default:
           ErrorStatus = AAC_DEC_UNKNOWN;

libAACdec/src/aacdecoder.h

@@ -111,6 +111,7 @@ amm-info@iis.fraunhofer.de
 #include "aacdec_drc.h"
 
  #include "pcmutils_lib.h"
+ #include "limiter.h"
 
 
 /* Capabilities flags */
@@ -215,6 +216,12 @@ struct AAC_DECODER_INSTANCE {
   CAncData      ancData;                             /*!< structure to handle ancillary data         */
 
   HANDLE_PCM_DOWNMIX  hPcmUtils;                     /*!< privat data for the PCM utils.             */
+  TDLimiterPtr hLimiter;                             /*!< Handle of time domain limiter.             */
+  UCHAR        limiterEnableUser;                    /*!< The limiter configuration requested by the library user */
+  UCHAR        limiterEnableCurr;                    /*!< The current limiter configuration.         */
+
+  FIXP_DBL     extGain[1];                           /*!< Gain that must be applied to the output signal. */
+  UINT         extGainDelay;                         /*!< Delay that must be accounted for extGain. */
 
 };
 

libAACdec/src/aacdecoder_lib.cpp

@@ -110,7 +110,7 @@ amm-info@iis.fraunhofer.de
 /* Decoder library info */
 #define AACDECODER_LIB_VL0 2
 #define AACDECODER_LIB_VL1 5
-#define AACDECODER_LIB_VL2 6
+#define AACDECODER_LIB_VL2 7
 #define AACDECODER_LIB_TITLE "AAC Decoder Lib"
 #define AACDECODER_LIB_BUILD_DATE __DATE__
 #define AACDECODER_LIB_BUILD_TIME __TIME__
@@ -397,12 +397,14 @@ aacDecoder_SetParam ( const HANDLE_AACDECODER  self,   /*!< Handle of the decode
   CConcealParams  *pConcealData = NULL;
   HANDLE_AAC_DRC hDrcInfo = NULL;
   HANDLE_PCM_DOWNMIX hPcmDmx = NULL;
+  TDLimiterPtr hPcmTdl = NULL;
 
   /* check decoder handle */
   if (self != NULL) {
     pConcealData = &self->concealCommonData;
     hDrcInfo = self->hDrcInfo;
     hPcmDmx = self->hPcmUtils;
+    hPcmTdl = self->hLimiter;
   } else {
     errorStatus = AAC_DEC_INVALID_HANDLE;
   }
@@ -486,6 +488,47 @@ aacDecoder_SetParam ( const HANDLE_AACDECODER  self,   /*!< Handle of the decode
     }
     break;
 
+
+  case AAC_PCM_LIMITER_ENABLE:
+    if (value < -1 || value > 1) {
+      return AAC_DEC_SET_PARAM_FAIL;
+    }
+    if (self == NULL) {
+      return AAC_DEC_INVALID_HANDLE;
+    }
+    self->limiterEnableUser = value;
+    break;
+
+  case AAC_PCM_LIMITER_ATTACK_TIME:
+    if (value <= 0) {  /* module function converts value to unsigned */
+      return AAC_DEC_SET_PARAM_FAIL;
+    }
+    switch (setLimiterAttack(hPcmTdl, value)) {
+    case TDLIMIT_OK:
+      break;
+    case TDLIMIT_INVALID_HANDLE:
+      return AAC_DEC_INVALID_HANDLE;
+    case TDLIMIT_INVALID_PARAMETER:
+    default:
+      return AAC_DEC_SET_PARAM_FAIL;
+    }
+    break;
+
+  case AAC_PCM_LIMITER_RELEAS_TIME:
+    if (value <= 0) {  /* module function converts value to unsigned */
+      return AAC_DEC_SET_PARAM_FAIL;
+    }
+    switch (setLimiterRelease(hPcmTdl, value)) {
+    case TDLIMIT_OK:
+      break;
+    case TDLIMIT_INVALID_HANDLE:
+      return AAC_DEC_INVALID_HANDLE;
+    case TDLIMIT_INVALID_PARAMETER:
+    default:
+      return AAC_DEC_SET_PARAM_FAIL;
+    }
+    break;
+
   case AAC_PCM_OUTPUT_CHANNEL_MAPPING:
     switch (value) {
       case 0:
@@ -632,6 +675,14 @@ LINKSPEC_CPP HANDLE_AACDECODER aacDecoder_Open(TRANSPORT_TYPE transportFmt, UINT
     goto bail;
   }
 
+  aacDec->hLimiter = createLimiter(TDL_ATTACK_DEFAULT_MS, TDL_RELEASE_DEFAULT_MS, SAMPLE_MAX, (8), 96000);
+  if (NULL == aacDec->hLimiter) {
+    err = -1;
+    goto bail;
+  }
+  aacDec->limiterEnableUser = (UCHAR)-1;
+  aacDec->limiterEnableCurr = 0;
+
 
 
   /* Assure that all modules have same delay */
@@ -807,6 +858,17 @@ LINKSPEC_CPP AAC_DECODER_ERROR aacDecoder_DecodeFrame(
       self->streamInfo.numTotalBytes = 0;
     }
 
+    if (self->limiterEnableUser==(UCHAR)-1) {
+      /* Enbale limiter for all non-lowdelay AOT's. */
+      self->limiterEnableCurr = ( self->flags & (AC_LD|AC_ELD) ) ? 0 : 1;
+    }
+    else {
+      /* Use limiter configuration as requested. */
+      self->limiterEnableCurr = self->limiterEnableUser;
+    }
+    /* reset limiter gain on a per frame basis */
+    self->extGain[0] = FL2FXCONST_DBL(1.0f/(float)(1<<TDL_GAIN_SCALING));
+
 
     ErrorStatus = CAacDecoder_DecodeFrame(self,
                                           flags | (fTpConceal ? AACDEC_CONCEAL : 0),
@@ -909,6 +971,7 @@ LINKSPEC_CPP AAC_DECODER_ERROR aacDecoder_DecodeFrame(
 
 
     {
+    INT pcmLimiterScale = 0;
     PCMDMX_ERROR dmxErr = PCMDMX_OK;
     if ( flags & (AACDEC_INTR | AACDEC_CLRHIST) ) {
       /* delete data from the past (e.g. mixdown coeficients) */
@@ -924,13 +987,34 @@ LINKSPEC_CPP AAC_DECODER_ERROR aacDecoder_DecodeFrame(
             self->channelType,
             self->channelIndices,
             self->channelOutputMapping,
-            NULL
+            (self->limiterEnableCurr) ? &pcmLimiterScale : NULL
       );
     if (dmxErr == PCMDMX_INVALID_MODE) {
       /* Announce the framework that the current combination of channel configuration and downmix
        * settings are not know to produce a predictable behavior and thus maybe produce strange output. */
       ErrorStatus = AAC_DEC_DECODE_FRAME_ERROR;
     }
+
+    if ( flags & AACDEC_CLRHIST ) {
+      /* Delete the delayed signal. */
+      resetLimiter(self->hLimiter);
+    }
+    if (self->limiterEnableCurr)
+    {
+      /* Set actual signal parameters */
+      setLimiterNChannels(self->hLimiter, self->streamInfo.numChannels);
+      setLimiterSampleRate(self->hLimiter, self->streamInfo.sampleRate);
+
+      applyLimiter(
+              self->hLimiter,
+              pTimeData,
+              self->extGain,
+             &pcmLimiterScale,
+              1,
+              self->extGainDelay,
+              self->streamInfo.frameSize
+              );
+    }
     }
 
 
@@ -956,6 +1040,9 @@ LINKSPEC_CPP void aacDecoder_Close ( HANDLE_AACDECODER self )
     return;
 
 
+  if (self->hLimiter != NULL) {
+    destroyLimiter(self->hLimiter);
+  }
 
   if (self->hPcmUtils != NULL) {
     pcmDmx_Close( &self->hPcmUtils );

libPCMutils/src/pcmutils_lib.cpp

@@ -148,7 +148,7 @@ amm-info@iis.fraunhofer.de
 /* Decoder library info */
 #define PCMDMX_LIB_VL0 2
 #define PCMDMX_LIB_VL1 4
-#define PCMDMX_LIB_VL2 1
+#define PCMDMX_LIB_VL2 2
 #define PCMDMX_LIB_TITLE "PCM Downmix Lib"
 #define PCMDMX_LIB_BUILD_DATE __DATE__
 #define PCMDMX_LIB_BUILD_TIME __TIME__