Strip out a large unneeded portion of the Speex stereo decoding function, and port the rest of it to fixed point. Disable the unneeded stereo float decoding function. Correct the output buffer size and change some minor syntactic stuff in speex.c

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@15554 a1c6a512-1295-4272-9138-f99709370657

2 files changed, 37 insertions, 20 deletions

diff --git a/apps/codecs/libspeex/speex/speex_stereo.h b/apps/codecs/libspeex/speex/speex_stereo.h
index ea2f976a26..904e9b092e 100644
--- a/apps/codecs/libspeex/speex/speex_stereo.h
+++ b/apps/codecs/libspeex/speex/speex_stereo.h
@@ -48,17 +48,29 @@ extern "C" {
 
 /** State used for decoding (intensity) stereo information */
 typedef struct SpeexStereoState {
+#ifndef FIXED_POINT
    float balance;      /**< Left/right balance info */
    float e_ratio;      /**< Ratio of energies: E(left+right)/[E(left)+E(right)]  */
    float smooth_left;  /**< Smoothed left channel gain */
    float smooth_right; /**< Smoothed right channel gain */
    float reserved1;    /**< Reserved for future use */
    float reserved2;    /**< Reserved for future use */
+#else
+   spx_int32_t balance;      /**< Left/right balance info */
+   spx_int16_t e_ratio;      /**< Ratio of energies: E(left+right)/[E(left)+E(right)]  */
+   spx_int16_t smooth_left;  /**< Smoothed left channel gain */
+   spx_int16_t smooth_right; /**< Smoothed right channel gain */
+   spx_int32_t reserved1;    /**< Reserved for future use */
+   spx_int32_t reserved2;    /**< Reserved for future use */
+#endif
 } SpeexStereoState;
 
 /** Initialization value for a stereo state */
+#ifndef FIXED_POINT
 #define SPEEX_STEREO_STATE_INIT {1,.5,1,1,0,0}
-
+#else
+#define SPEEX_STEREO_STATE_INIT {65536,16384,16384,16384,0,0}
+#endif
 /** Transforms a stereo frame into a mono frame and stores intensity stereo info in 'bits' */
 void speex_encode_stereo(float *data, int frame_size, SpeexBits *bits);
 
diff --git a/apps/codecs/libspeex/stereo.c b/apps/codecs/libspeex/stereo.c
index b0c65b812f..695dfe0fb0 100644
--- a/apps/codecs/libspeex/stereo.c
+++ b/apps/codecs/libspeex/stereo.c
@@ -35,11 +35,16 @@
 
 #include <speex/speex_stereo.h>
 #include <speex/speex_callbacks.h>
+#include "math_approx.h"
 #include "vq.h"
 #include <math.h>
 
 /*float e_ratio_quant[4] = {1, 1.26, 1.587, 2};*/
+#ifndef FIXED_POINT
 static const float e_ratio_quant[4] = {.25f, .315f, .397f, .5f};
+#else
+static const spx_word16_t e_ratio_quant[4] = {8192, 10332, 13009, 16384};
+#endif
 
 #ifndef SPEEX_DISABLE_ENCODER
 void speex_encode_stereo(float *data, int frame_size, SpeexBits *bits)
@@ -115,8 +120,10 @@ void speex_encode_stereo_int(spx_int16_t *data, int frame_size, SpeexBits *bits)
    tmp=vq_index(&e_ratio, e_ratio_quant, 1, 4);
    speex_bits_pack(bits, tmp, 2);
 }
-#endif
+#endif /* SPEEX_DISABLE_ENCODER */
 
+/* We don't want to decode to floats yet, disable */
+#if 0
 void speex_decode_stereo(float *data, int frame_size, SpeexStereoState *stereo)
 {
    float balance, e_ratio;
@@ -145,48 +152,46 @@ void speex_decode_stereo(float *data, int frame_size, SpeexStereoState *stereo)
       data[2*i+1] = stereo->smooth_right*ftmp;
    }
 }
+#endif
 
 void speex_decode_stereo_int(spx_int16_t *data, int frame_size, SpeexStereoState *stereo)
 {
-   float balance, e_ratio;
    int i;
-   float e_tot=0, e_left, e_right, e_sum;
+   spx_word32_t balance;
+   spx_word16_t e_left, e_right, e_ratio;
 
    balance=stereo->balance;
    e_ratio=stereo->e_ratio;
-   for (i=frame_size-1;i>=0;i--)
-   {
-      e_tot += ((float)data[i])*data[i];
-   }
-   e_sum=e_tot/e_ratio;
-   e_left  = e_sum*balance / (1+balance);
-   e_right = e_sum-e_left;
 
-   e_left  = sqrt(e_left/(e_tot+.01));
-   e_right = sqrt(e_right/(e_tot+.01));
+   /* These two are Q14, with max value just below 2. */
+   e_right = DIV32(QCONST32(1., 22), spx_sqrt(MULT16_32_Q15(e_ratio, ADD32(QCONST32(1., 16), balance))));
+   e_left = SHR32(MULT16_16(spx_sqrt(balance), e_right), 8);
 
    for (i=frame_size-1;i>=0;i--)
    {
-      float ftmp=data[i];
-      stereo->smooth_left  = .98*stereo->smooth_left  + .02*e_left;
-      stereo->smooth_right = .98*stereo->smooth_right + .02*e_right;
-      data[2*i] = stereo->smooth_left*ftmp;
-      data[2*i+1] = stereo->smooth_right*ftmp;
+      spx_word16_t tmp=data[i];
+      stereo->smooth_left = EXTRACT16(PSHR32(MAC16_16(MULT16_16(stereo->smooth_left, QCONST16(0.98, 15)), e_left, QCONST16(0.02, 15)), 15));
+      stereo->smooth_right = EXTRACT16(PSHR32(MAC16_16(MULT16_16(stereo->smooth_right, QCONST16(0.98, 15)), e_right, QCONST16(0.02, 15)), 15));
+      data[2*i] = MULT16_16_P14(stereo->smooth_left, tmp);
+      data[2*i+1] = MULT16_16_P14(stereo->smooth_right, tmp);
    }
 }
 
 int speex_std_stereo_request_handler(SpeexBits *bits, void *state, void *data)
 {
    SpeexStereoState *stereo;
-   float sign=1;
+   spx_word16_t sign=1;
    int tmp;
 
    stereo = (SpeexStereoState*)data;
    if (speex_bits_unpack_unsigned(bits, 1))
       sign=-1;
    tmp = speex_bits_unpack_unsigned(bits, 5);
+#ifndef FIXED_POINT
    stereo->balance = exp(sign*.25*tmp);
-
+#else
+   stereo->balance = spx_exp(MULT16_16(sign, SHL16(tmp, 9)));
+#endif
    tmp = speex_bits_unpack_unsigned(bits, 2);
    stereo->e_ratio = e_ratio_quant[tmp];