From 206a397c708738c08edc0229881018edcb8ea793 Mon Sep 17 00:00:00 2001
From: Jean-Michel Trivi <jmtrivi@google.com>
Date: Tue, 27 Aug 2013 16:35:59 -0700
Subject: Decoder parse ASC

* AAC-Decoder

   - Add support for explicit backward compatible signaling via ASC extension.

Bug 9428126

Change-Id: I0cb8226da07e3684bbb7eb95d10b6040973aa0f6
---
 libMpegTPDec/src/tpdec_asc.cpp | 59 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

(limited to 'libMpegTPDec/src/tpdec_asc.cpp')

diff --git a/libMpegTPDec/src/tpdec_asc.cpp b/libMpegTPDec/src/tpdec_asc.cpp
index 59ad58b..4d7cc02 100644
--- a/libMpegTPDec/src/tpdec_asc.cpp
+++ b/libMpegTPDec/src/tpdec_asc.cpp
@@ -834,6 +834,62 @@ bail:
 #endif /* TP_ELD_ENABLE */
 
 
+static
+TRANSPORTDEC_ERROR AudioSpecificConfig_ExtensionParse(CSAudioSpecificConfig *self, HANDLE_FDK_BITSTREAM bs, CSTpCallBacks *cb)
+{
+  TP_ASC_EXTENSION_ID  lastAscExt, ascExtId = ASCEXT_UNKOWN;
+  INT  bitsAvailable = (INT)FDKgetValidBits(bs);
+
+  while (bitsAvailable >= 11)
+  {
+    lastAscExt = ascExtId;
+    ascExtId   = (TP_ASC_EXTENSION_ID)FDKreadBits(bs, 11);
+    bitsAvailable -= 11;
+
+    switch (ascExtId) {
+    case ASCEXT_SBR:    /* 0x2b7 */
+      if ( (self->m_extensionAudioObjectType != AOT_SBR) && (bitsAvailable >= 5) ) {
+        self->m_extensionAudioObjectType = getAOT(bs);
+
+        if ( (self->m_extensionAudioObjectType == AOT_SBR)
+          || (self->m_extensionAudioObjectType == AOT_ER_BSAC) )
+        { /* Get SBR extension configuration */
+          self->m_sbrPresentFlag = FDKreadBits(bs, 1);
+          bitsAvailable -= 1;
+
+          if ( self->m_sbrPresentFlag == 1 ) {
+            self->m_extensionSamplingFrequency = getSampleRate(bs, &self->m_extensionSamplingFrequencyIndex, 4);
+
+            if ((INT)self->m_extensionSamplingFrequency <= 0) {
+              return TRANSPORTDEC_PARSE_ERROR;
+            }
+          }
+          if ( self->m_extensionAudioObjectType == AOT_ER_BSAC ) {
+            self->m_extensionChannelConfiguration = FDKreadBits(bs, 4);
+            bitsAvailable -= 4;
+          }
+        }
+        /* Update counter because of variable length fields (AOT and sampling rate) */
+        bitsAvailable = (INT)FDKgetValidBits(bs);
+      }
+      break;
+    case ASCEXT_PS:     /* 0x548 */
+      if ( (lastAscExt == ASCEXT_SBR)
+        && (self->m_extensionAudioObjectType == AOT_SBR)
+        && (bitsAvailable > 0) )
+      { /* Get PS extension configuration */
+        self->m_psPresentFlag = FDKreadBits(bs, 1);
+        bitsAvailable -= 1;
+      }
+      break;
+    default:
+      /* Just ignore anything. */
+      return TRANSPORTDEC_OK;
+    }
+  }
+
+  return TRANSPORTDEC_OK;
+}
 
 /*
  * API Functions
@@ -984,6 +1040,9 @@ TRANSPORTDEC_ERROR AudioSpecificConfig_Parse(
       break;
   }
 
+  if (fExplicitBackwardCompatible) {
+    ErrorStatus = AudioSpecificConfig_ExtensionParse(self, bs, cb);
+  }
 
   return (ErrorStatus);
 }
-- 
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