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Commit 32fa3c6f authored by Glenn Kasten's avatar Glenn Kasten
Browse files

Remove AUDIO_CHANNEL_OUT_SURROUND 

and corresponding downmix effect

Change-Id: I1576aa373ca7acbb84d7742bacbd9c2da04a7a4c
parent bff80465

media/libeffects/downmix/EffectDownmix.c

+0 −63
Original line number Diff line number Diff line
@@ -31,7 +31,6 @@ 
#define MINUS_3_DB_IN_Q19_12 2896 // -3dB = 0.707 * 2^12 = 2896



typedef enum {

    CHANNEL_MASK_SURROUND = AUDIO_CHANNEL_OUT_SURROUND,

    CHANNEL_MASK_QUAD_BACK = AUDIO_CHANNEL_OUT_QUAD,

    // like AUDIO_CHANNEL_OUT_QUAD with *_SIDE_* instead of *_BACK_*, same channel order

    CHANNEL_MASK_QUAD_SIDE =
@@ -340,9 +339,6 @@ static int Downmix_Process(effect_handle_t self, 
        case CHANNEL_MASK_QUAD_SIDE:

            Downmix_foldFromQuad(pSrc, pDst, numFrames, accumulate);

            break;

        case CHANNEL_MASK_SURROUND:

            Downmix_foldFromSurround(pSrc, pDst, numFrames, accumulate);

            break;

        case CHANNEL_MASK_5POINT1_BACK:

        case CHANNEL_MASK_5POINT1_SIDE:

            Downmix_foldFrom5Point1(pSrc, pDst, numFrames, accumulate);
@@ -827,65 +823,6 @@ void Downmix_foldFromQuad(int16_t *pSrc, int16_t*pDst, size_t numFrames, bool ac 
}





/*----------------------------------------------------------------------------

 * Downmix_foldFromSurround()

 *----------------------------------------------------------------------------

 * Purpose:

 * downmix a "surround sound" (mono rear) signal to stereo

 *

 * Inputs:

 *  pSrc       surround signal to downmix

 *  numFrames  the number of surround frames to downmix

 *  accumulate whether to mix (when true) the result of the downmix with the contents of pDst,

 *               or overwrite pDst (when false)

 *

 * Outputs:

 *  pDst       downmixed stereo audio samples

 *

 *----------------------------------------------------------------------------

 */

void Downmix_foldFromSurround(int16_t *pSrc, int16_t*pDst, size_t numFrames, bool accumulate) {

    int32_t lt, rt, centerPlusRearContrib; // samples in Q19.12 format

    // sample at index 0 is FL

    // sample at index 1 is FR

    // sample at index 2 is FC

    // sample at index 3 is RC

    // code is mostly duplicated between the two values of accumulate to avoid repeating the test

    // for every sample

    if (accumulate) {

        while (numFrames) {

            // centerPlusRearContrib = FC(-3dB) + RC(-3dB)

            centerPlusRearContrib = (pSrc[2] * MINUS_3_DB_IN_Q19_12) + (pSrc[3] * MINUS_3_DB_IN_Q19_12);

            // FL + centerPlusRearContrib

            lt = (pSrc[0] << 12) + centerPlusRearContrib;

            // FR + centerPlusRearContrib

            rt = (pSrc[1] << 12) + centerPlusRearContrib;

            // accumulate in destination

            pDst[0] = clamp16(pDst[0] + (lt >> 13));

            pDst[1] = clamp16(pDst[1] + (rt >> 13));

            pSrc += 4;

            pDst += 2;

            numFrames--;

        }

    } else { // same code as above but without adding and clamping pDst[i] to itself

        while (numFrames) {

            // centerPlusRearContrib = FC(-3dB) + RC(-3dB)

            centerPlusRearContrib = (pSrc[2] * MINUS_3_DB_IN_Q19_12) + (pSrc[3] * MINUS_3_DB_IN_Q19_12);

            // FL + centerPlusRearContrib

            lt = (pSrc[0] << 12) + centerPlusRearContrib;

            // FR + centerPlusRearContrib

            rt = (pSrc[1] << 12) + centerPlusRearContrib;

            // store in destination

            pDst[0] = clamp16(lt >> 13); // differs from when accumulate is true above

            pDst[1] = clamp16(rt >> 13); // differs from when accumulate is true above

            pSrc += 4;

            pDst += 2;

            numFrames--;

        }

    }

}





/*----------------------------------------------------------------------------

 * Downmix_foldFrom5Point1()

 *----------------------------------------------------------------------------

media/libeffects/downmix/EffectDownmix.h

+0 −1
Original line number Diff line number Diff line
@@ -97,7 +97,6 @@ int Downmix_setParameter(downmix_object_t *pDownmixer, int32_t param, uint32_t s 
int Downmix_getParameter(downmix_object_t *pDownmixer, int32_t param, uint32_t *pSize, void *pValue);



void Downmix_foldFromQuad(int16_t *pSrc, int16_t*pDst, size_t numFrames, bool accumulate);

void Downmix_foldFromSurround(int16_t *pSrc, int16_t*pDst, size_t numFrames, bool accumulate);

void Downmix_foldFrom5Point1(int16_t *pSrc, int16_t*pDst, size_t numFrames, bool accumulate);

void Downmix_foldFrom7Point1(int16_t *pSrc, int16_t*pDst, size_t numFrames, bool accumulate);

bool Downmix_foldGeneric(