diff options
| -rw-r--r-- | Alc/uhjfilter.c | 28 | ||||
| -rw-r--r-- | Alc/uhjfilter.h | 6 |
2 files changed, 17 insertions, 17 deletions
diff --git a/Alc/uhjfilter.c b/Alc/uhjfilter.c index eef477e3..42b0bc40 100644 --- a/Alc/uhjfilter.c +++ b/Alc/uhjfilter.c @@ -18,23 +18,20 @@ static const ALfloat Filter2CoeffSqr[4] = { static void allpass_process(AllPassState *state, ALfloat *restrict dst, const ALfloat *restrict src, const ALfloat aa, ALsizei todo) { - ALfloat x0 = state->x[0]; - ALfloat x1 = state->x[1]; - ALfloat y0 = state->y[0]; - ALfloat y1 = state->y[1]; + ALfloat z1 = state->z[0]; + ALfloat z2 = state->z[1]; ALsizei i; for(i = 0;i < todo;i++) { - dst[i] = aa*(src[i] + y1) - x1; - y1 = y0; y0 = dst[i]; - x1 = x0; x0 = src[i]; + ALfloat input = src[i]; + ALfloat output = input*aa + z1; + z1 = z2; z2 = output*aa - input; + dst[i] = output; } - state->x[0] = x0; - state->x[1] = x1; - state->y[0] = y0; - state->y[1] = y1; + state->z[0] = z1; + state->z[1] = z2; } @@ -69,6 +66,7 @@ void EncodeUhj2(Uhj2Encoder *enc, ALfloat *restrict LeftOut, ALfloat *restrict R for(base = 0;base < SamplesToDo;) { ALsizei todo = mini(SamplesToDo - base, MAX_UPDATE_SAMPLES); + ASSUME(todo > 0); /* D = 0.6554516*Y */ for(i = 0;i < todo;i++) @@ -76,14 +74,15 @@ void EncodeUhj2(Uhj2Encoder *enc, ALfloat *restrict LeftOut, ALfloat *restrict R allpass_process(&enc->Filter1_Y[0], temp[1], temp[0], Filter1CoeffSqr[0], todo); allpass_process(&enc->Filter1_Y[1], temp[0], temp[1], Filter1CoeffSqr[1], todo); allpass_process(&enc->Filter1_Y[2], temp[1], temp[0], Filter1CoeffSqr[2], todo); + allpass_process(&enc->Filter1_Y[3], temp[0], temp[1], Filter1CoeffSqr[3], todo); /* NOTE: Filter1 requires a 1 sample delay for the final output, so * take the last processed sample from the previous run as the first * output sample. */ - D[0] = enc->Filter1_Y[3].y[0]; - allpass_process(&enc->Filter1_Y[3], temp[0], temp[1], Filter1CoeffSqr[3], todo); + D[0] = enc->LastY; for(i = 1;i < todo;i++) D[i] = temp[0][i-1]; + enc->LastY = temp[0][i-1]; /* D += j(-0.3420201*W + 0.5098604*X) */ for(i = 0;i < todo;i++) @@ -103,10 +102,11 @@ void EncodeUhj2(Uhj2Encoder *enc, ALfloat *restrict LeftOut, ALfloat *restrict R allpass_process(&enc->Filter1_WX[0], temp[1], temp[0], Filter1CoeffSqr[0], todo); allpass_process(&enc->Filter1_WX[1], temp[0], temp[1], Filter1CoeffSqr[1], todo); allpass_process(&enc->Filter1_WX[2], temp[1], temp[0], Filter1CoeffSqr[2], todo); - S[0] = enc->Filter1_WX[3].y[0]; allpass_process(&enc->Filter1_WX[3], temp[0], temp[1], Filter1CoeffSqr[3], todo); + S[0] = enc->LastWX; for(i = 1;i < todo;i++) S[i] = temp[0][i-1]; + enc->LastWX = temp[0][i-1]; /* Left = (S + D)/2.0 */ for(i = 0;i < todo;i++) diff --git a/Alc/uhjfilter.h b/Alc/uhjfilter.h index 48c2fde6..e773e0a7 100644 --- a/Alc/uhjfilter.h +++ b/Alc/uhjfilter.h @@ -6,8 +6,7 @@ #include "alMain.h" typedef struct AllPassState { - ALfloat x[2]; /* Last two input samples */ - ALfloat y[2]; /* Last two output samples */ + ALfloat z[2]; } AllPassState; /* Encoding 2-channel UHJ from B-Format is done as: @@ -36,9 +35,10 @@ typedef struct AllPassState { */ typedef struct Uhj2Encoder { - AllPassState Filter1_WX[4]; AllPassState Filter1_Y[4]; AllPassState Filter2_WX[4]; + AllPassState Filter1_WX[4]; + ALfloat LastY, LastWX; } Uhj2Encoder; /* Encodes a 2-channel UHJ (stereo-compatible) signal from a B-Format input |