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Commit eda3e932 authored by Andy Hung's avatar Andy Hung
Browse files

Downmix: Use internal ChannelMix if Downmix Effect unsupported 

Test: atest AudioTrackTest#testDownmix
Bug: 202162797
Change-Id: I7f7f389c320510c8876cb822393bb101460a403b
parent 25cfa13e

media/libaudioprocessing/AudioMixer.cpp

+18 −0
Original line number Diff line number Diff line
@@ -193,6 +193,24 @@ status_t AudioMixer::Track::prepareForDownmix() 
        // mDownmixerBufferProvider reset below.

    }



    // See if we should use our built-in non-effect downmixer.

    if (mMixerInFormat == AUDIO_FORMAT_PCM_FLOAT

            && mMixerChannelMask == AUDIO_CHANNEL_OUT_STEREO

            && audio_channel_mask_get_representation(channelMask)

                    == AUDIO_CHANNEL_REPRESENTATION_POSITION) {

        mDownmixerBufferProvider.reset(new ChannelMixBufferProvider(channelMask,

                mMixerChannelMask, mMixerInFormat, kCopyBufferFrameCount));

        if (static_cast<ChannelMixBufferProvider *>(mDownmixerBufferProvider.get())

                ->isValid()) {

            mDownmixRequiresFormat = mMixerInFormat;

            reconfigureBufferProviders();

            ALOGD("%s: Fallback using ChannelMix", __func__);

            return NO_ERROR;

        } else {

            ALOGD("%s: ChannelMix not supported for channel mask %#x", __func__, channelMask);

        }

    }



    // Effect downmixer does not accept the channel conversion.  Let's use our remixer.

    mDownmixerBufferProvider.reset(new RemixBufferProvider(channelMask,

            mMixerChannelMask, mMixerInFormat, kCopyBufferFrameCount));

media/libaudioprocessing/BufferProviders.cpp

+23 −0
Original line number Diff line number Diff line
@@ -364,6 +364,29 @@ void RemixBufferProvider::copyFrames(void *dst, const void *src, size_t frames) 
            src, mInputChannels, mIdxAry, mSampleSize, frames);

}



ChannelMixBufferProvider::ChannelMixBufferProvider(audio_channel_mask_t inputChannelMask,

        audio_channel_mask_t outputChannelMask, audio_format_t format,

        size_t bufferFrameCount) :

        CopyBufferProvider(

                audio_bytes_per_sample(format)

                    * audio_channel_count_from_out_mask(inputChannelMask),

                audio_bytes_per_sample(format)

                    * audio_channel_count_from_out_mask(outputChannelMask),

                bufferFrameCount)

{

    ALOGV("ChannelMixBufferProvider(%p)(%#x, %#x, %#x)",

            this, format, inputChannelMask, outputChannelMask);

    if (outputChannelMask == AUDIO_CHANNEL_OUT_STEREO && format == AUDIO_FORMAT_PCM_FLOAT) {

        mIsValid = mChannelMix.setInputChannelMask(inputChannelMask);

    }

}



void ChannelMixBufferProvider::copyFrames(void *dst, const void *src, size_t frames)

{

    mChannelMix.process(static_cast<const float *>(src), static_cast<float *>(dst),

            frames, false /* accumulate */);

}



ReformatBufferProvider::ReformatBufferProvider(int32_t channelCount,

        audio_format_t inputFormat, audio_format_t outputFormat,

        size_t bufferFrameCount) :

media/libaudioprocessing/include/media/BufferProviders.h

+18 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include <stdint.h>

#include <sys/types.h>



#include <audio_utils/ChannelMix.h>

#include <media/AudioBufferProvider.h>

#include <media/AudioResamplerPublic.h>

#include <system/audio.h>
@@ -129,6 +130,23 @@ protected: 
    static const int32_t SESSION_ID_INVALID_AND_IGNORED = -2;

};



// ChannelMixBufferProvider derives from CopyBufferProvider to perform an

// downmix to the proper channel count and mask.

class ChannelMixBufferProvider : public CopyBufferProvider {

public:

    ChannelMixBufferProvider(audio_channel_mask_t inputChannelMask,

            audio_channel_mask_t outputChannelMask, audio_format_t format,

            size_t bufferFrameCount);



    void copyFrames(void *dst, const void *src, size_t frames) override;



    bool isValid() const { return mIsValid; }



protected:

    audio_utils::channels::ChannelMix mChannelMix;

    bool mIsValid = false;

};



// RemixBufferProvider derives from CopyBufferProvider to perform an

// upmix or downmix to the proper channel count and mask.

class RemixBufferProvider : public CopyBufferProvider {