AAC Decoder: flush/seek improvements

Improve flushing and seeking.
Add field to the API stream info structure signaling the additional output
 delay for flushing and delay compensation.

Bug 9428126

Change-Id: I808412905563ea3de50a2e77a9b5dfee829cd2ed

3 files changed, 47 insertions, 5 deletions

diff --git a/libSBRdec/include/sbrdecoder.h b/libSBRdec/include/sbrdecoder.h
index cb06dbc..36a4739 100644
--- a/libSBRdec/include/sbrdecoder.h
+++ b/libSBRdec/include/sbrdecoder.h
@@ -145,6 +145,8 @@ typedef enum
   SBR_SYSTEM_BITSTREAM_DELAY,          /*!< System: Switch to enable an additional SBR bitstream delay of one frame. */
   SBR_QMF_MODE,                        /*!< Set QMF mode, either complex or low power. */
   SBR_LD_QMF_TIME_ALIGN,               /*!< Set QMF type, either LD-MPS or CLDFB. Relevant for ELD streams only. */
+  SBR_FLUSH_DATA,                      /*!< Set internal state to flush the decoder with the next process call. */
+  SBR_CLEAR_HISTORY,                   /*!< Clear all internal states (delay lines, QMF states, ...). */
   SBR_BS_INTERRUPTION                  /*!< Signal bit stream interruption. Value is ignored. */
 } SBRDEC_PARAM;
 
diff --git a/libSBRdec/src/env_extr.h b/libSBRdec/src/env_extr.h
index 5db6d3d..ddbfa18 100644
--- a/libSBRdec/src/env_extr.h
+++ b/libSBRdec/src/env_extr.h
@@ -179,6 +179,8 @@ typedef FREQ_BAND_DATA *HANDLE_FREQ_BAND_DATA;
 #define SBRDEC_LOW_POWER      16  /* Flag indicating that Low Power QMF mode shall be used. */
 #define SBRDEC_PS_DECODED     32  /* Flag indicating that PS was decoded and rendered. */
 #define SBRDEC_LD_MPS_QMF    512  /* Flag indicating that the LD-MPS QMF shall be used. */
+#define SBRDEC_FLUSH       16384  /* Flag is used to flush all elements in use. */
+#define SBRDEC_FORCE_RESET 32768  /* Flag is used to force a reset of all elements in use. */
 
 #define SBRDEC_HDR_STAT_RESET  1
 #define SBRDEC_HDR_STAT_UPDATE 2
diff --git a/libSBRdec/src/sbrdecoder.cpp b/libSBRdec/src/sbrdecoder.cpp
index 5734020..bed23c7 100644
--- a/libSBRdec/src/sbrdecoder.cpp
+++ b/libSBRdec/src/sbrdecoder.cpp
@@ -137,7 +137,7 @@ amm-info@iis.fraunhofer.de
 /* Decoder library info */
 #define SBRDECODER_LIB_VL0 2
 #define SBRDECODER_LIB_VL1 2
-#define SBRDECODER_LIB_VL2 4
+#define SBRDECODER_LIB_VL2 5
 #define SBRDECODER_LIB_TITLE "SBR Decoder"
 #define SBRDECODER_LIB_BUILD_DATE __DATE__
 #define SBRDECODER_LIB_BUILD_TIME __TIME__
@@ -444,6 +444,7 @@ SBR_ERROR sbrDecoder_InitElement (
      && self->coreCodec == coreCodec
      && self->pSbrElement[elementIndex] != NULL
      && self->pSbrElement[elementIndex]->elementID == elementID
+     && !(self->flags & SBRDEC_FORCE_RESET)
      )
   {
      /* Nothing to do */
@@ -550,8 +551,9 @@ bail:
     if (nSbrElementsStart < self->numSbrElements) {
       /* Free the memory allocated for this element */
       sbrDecoder_DestroyElement( self, elementIndex );
-    } else if (self->pSbrElement[elementIndex] != NULL) {
-      /* Set error flag to trigger concealment */
+    } else if ( (self->pSbrElement[elementIndex] != NULL)
+             && (elementIndex < (8)))
+    { /* Set error flag to trigger concealment */
       self->pSbrElement[elementIndex]->frameErrorFlag[self->pSbrElement[elementIndex]->useFrameSlot] = 1;
     }
   }
@@ -728,6 +730,24 @@ SBR_ERROR sbrDecoder_SetParam (HANDLE_SBRDECODER   self,
       }
     }
     break;
+  case SBR_FLUSH_DATA:
+    if (value != 0) {
+      if (self == NULL) {
+        errorStatus = SBRDEC_NOT_INITIALIZED;
+      } else {
+        self->flags |= SBRDEC_FLUSH;
+      }
+    }
+    break;
+  case SBR_CLEAR_HISTORY:
+    if (value != 0) {
+      if (self == NULL) {
+        errorStatus = SBRDEC_NOT_INITIALIZED;
+      } else {
+        self->flags |= SBRDEC_FORCE_RESET;
+      }
+    }
+    break;
   case SBR_BS_INTERRUPTION:
     {
       int elementIndex;
@@ -738,7 +758,8 @@ SBR_ERROR sbrDecoder_SetParam (HANDLE_SBRDECODER   self,
       }
 
       /* Loop over SBR elements */
-      for (elementIndex = 0; elementIndex < self->numSbrElements; elementIndex++)
+      for (elementIndex = 0; elementIndex < self->numSbrElements; elementIndex++) {
+      if (self->pSbrElement[elementIndex] != NULL)
       {
         HANDLE_SBR_HEADER_DATA hSbrHeader;
         int headerIndex = getHeaderSlot(self->pSbrElement[elementIndex]->useFrameSlot,
@@ -750,7 +771,7 @@ SBR_ERROR sbrDecoder_SetParam (HANDLE_SBRDECODER   self,
            This switches off bitstream parsing until a new header arrives. */
         hSbrHeader->syncState = UPSAMPLING;
         hSbrHeader->status   |= SBRDEC_HDR_STAT_UPDATE;
-      }
+      } }
     }
     break;
   default:
@@ -1119,6 +1140,10 @@ SBR_ERROR sbrDecoder_Parse(
         }
       }
     }
+  } else {
+    /* The returned bit count will not be the actual payload size since we did not
+       parse the frame data. Return an error so that the caller can react respectively. */
+    errorStatus = SBRDEC_PARSE_ERROR;
   }
 
   if (!fDoDecodeSbrData) {
@@ -1198,6 +1223,15 @@ sbrDecoder_DecodeElement (
   int  stereo = (hSbrElement->elementID == ID_CPE) ? 1 : 0;
   int  numElementChannels = hSbrElement->nChannels; /* Number of channels of the current SBR element */
 
+  if (self->flags & SBRDEC_FLUSH) {
+    /* Move frame pointer to the next slot which is up to be decoded/applied next */
+    hSbrElement->useFrameSlot = (hSbrElement->useFrameSlot+1) % (self->numDelayFrames+1);
+    /* Update header and frame data pointer because they have already been set */
+    hSbrHeader = &self->sbrHeader[elementIndex][hSbrElement->useHeaderSlot[hSbrElement->useFrameSlot]];
+    hFrameDataLeft  = &hSbrElement->pSbrChannel[0]->frameData[hSbrElement->useFrameSlot];
+    hFrameDataRight = &hSbrElement->pSbrChannel[1]->frameData[hSbrElement->useFrameSlot];
+  }
+
   /* Update the header error flag */
   hSbrHeader->frameErrorFlag = hSbrElement->frameErrorFlag[hSbrElement->useFrameSlot];
 
@@ -1472,6 +1506,10 @@ SBR_ERROR sbrDecoder_Apply ( HANDLE_SBRDECODER   self,
 
 
 
+  /* Clear reset and flush flag because everything seems to be done successfully. */
+  self->flags &= ~SBRDEC_FORCE_RESET;
+  self->flags &= ~SBRDEC_FLUSH;
+
 bail:
 
   return errorStatus;