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Commit 4213e9db authored by Jean-Michel Trivi's avatar Jean-Michel Trivi
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Bug 7170947 Configure AAC decoder for mobile DRC settings 

Configure the AAC decoder to use the modile DRC settings when
 decoding streams with DRC metadata.
 Settings are:
 - target reference level of -12dB
 - DRC compression factor (attenuation) at max
These settings can be overridden by platform properties if the
 default values are to be modified.

Change-Id: If329fe566497685b735abe4e4b9a5e01697c063b
parent 0389cc09

media/libstagefright/codecs/aacdec/SoftAAC2.cpp

+37 −5
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
 */



#define LOG_TAG "SoftAAC2"

//#define LOG_NDEBUG 0

#include <utils/Log.h>



#include "SoftAAC2.h"
@@ -26,8 +27,13 @@ 


#define FILEREAD_MAX_LAYERS 2



#define DRC_DEFAULT_REF_LEVEL 108   /* 108*0.25dB = -27 dB below full scale (typical for movies) */

#define DRC_DEFAULT_MOBILE_REF_LEVEL 48  /* 48*-0.25dB = -12 dB below full scale for mobile conf */

#define DRC_DEFAULT_MOBILE_DRC_CUT   127 /* maximum compression of dynamic range for mobile conf */

#define MAX_CHANNEL_COUNT            6  /* maximum number of audio channels that can be decoded */

// names of properties that can be used to override the default DRC settings

#define PROP_DRC_OVERRIDE_REF_LEVEL  "aac_drc_reference_level"

#define PROP_DRC_OVERRIDE_CUT        "aac_drc_cut"

#define PROP_DRC_OVERRIDE_BOOST      "aac_drc_boost"



namespace android {
@@ -113,9 +119,35 @@ status_t SoftAAC2::initDecoder() { 
        }

    }

    mIsFirst = true;

    // the decoder will bypass all DRC processing during decode unless any of the DRC parameters

    //  is set, so here we just reset the DRC reference level to its default value.

    aacDecoder_SetParam(mAACDecoder, AAC_DRC_REFERENCE_LEVEL, DRC_DEFAULT_REF_LEVEL);



    // for streams that contain metadata, use the mobile profile DRC settings unless overridden

    // by platform properties:

    char value[PROPERTY_VALUE_MAX];

    //  * AAC_DRC_REFERENCE_LEVEL

    if (property_get(PROP_DRC_OVERRIDE_REF_LEVEL, value, NULL)) {

        unsigned refLevel = atoi(value);

        ALOGV("AAC decoder using AAC_DRC_REFERENCE_LEVEL of %d instead of %d",

                refLevel, DRC_DEFAULT_MOBILE_REF_LEVEL);

        aacDecoder_SetParam(mAACDecoder, AAC_DRC_REFERENCE_LEVEL, refLevel);

    } else {

        aacDecoder_SetParam(mAACDecoder, AAC_DRC_REFERENCE_LEVEL, DRC_DEFAULT_MOBILE_REF_LEVEL);

    }

    //  * AAC_DRC_ATTENUATION_FACTOR

    if (property_get(PROP_DRC_OVERRIDE_CUT, value, NULL)) {

        unsigned cut = atoi(value);

        ALOGV("AAC decoder using AAC_DRC_ATTENUATION_FACTOR of %d instead of %d",

                        cut, DRC_DEFAULT_MOBILE_DRC_CUT);

        aacDecoder_SetParam(mAACDecoder, AAC_DRC_ATTENUATION_FACTOR, cut);

    } else {

        aacDecoder_SetParam(mAACDecoder, AAC_DRC_ATTENUATION_FACTOR, DRC_DEFAULT_MOBILE_DRC_CUT);

    }

    //  * AAC_DRC_BOOST_FACTOR (note: no default, using cut)

    if (property_get(PROP_DRC_OVERRIDE_BOOST, value, NULL)) {

        unsigned boost = atoi(value);

        ALOGV("AAC decoder using AAC_DRC_BOOST_FACTOR of %d", boost);

        aacDecoder_SetParam(mAACDecoder, AAC_DRC_BOOST_FACTOR, boost);

    }



    return status;

}