[Ffmpeg-cvslog] r8627 - in trunk/libavcodec: wma.h wmadec.c
banan
subversion
Wed Apr 4 15:49:56 CEST 2007
Author: banan
Date: Wed Apr 4 15:49:55 2007
New Revision: 8627
Modified:
trunk/libavcodec/wma.h
trunk/libavcodec/wmadec.c
Log:
WMA decoder improvement, output closer to the dmo binary.
Patch by Ian Braithwaite ian braithwaite dot dk
[Ffmpeg-devel] WMA decoder improvement, 2007-03-28 15:50
Modified: trunk/libavcodec/wma.h
==============================================================================
--- trunk/libavcodec/wma.h (original)
+++ trunk/libavcodec/wma.h Wed Apr 4 15:49:55 2007
@@ -107,6 +107,7 @@ typedef struct WMACodecContext {
int block_pos; ///< current position in frame
uint8_t ms_stereo; ///< true if mid/side stereo mode
uint8_t channel_coded[MAX_CHANNELS]; ///< true if channel is coded
+ int exponents_bsize[MAX_CHANNELS]; ///< log2 ratio frame/exp. length
DECLARE_ALIGNED_16(float, exponents[MAX_CHANNELS][BLOCK_MAX_SIZE]);
float max_exponent[MAX_CHANNELS];
int16_t coefs1[MAX_CHANNELS][BLOCK_MAX_SIZE];
Modified: trunk/libavcodec/wmadec.c
==============================================================================
--- trunk/libavcodec/wmadec.c (original)
+++ trunk/libavcodec/wmadec.c Wed Apr 4 15:49:55 2007
@@ -130,35 +130,6 @@ static int wma_decode_init(AVCodecContex
}
/**
- * interpolate values for a bigger or smaller block. The block must
- * have multiple sizes
- */
-static void interpolate_array(float *scale, int old_size, int new_size)
-{
- int i, j, jincr, k;
- float v;
-
- if (new_size > old_size) {
- jincr = new_size / old_size;
- j = new_size;
- for(i = old_size - 1; i >=0; i--) {
- v = scale[i];
- k = jincr;
- do {
- scale[--j] = v;
- } while (--k);
- }
- } else if (new_size < old_size) {
- j = 0;
- jincr = old_size / new_size;
- for(i = 0; i < new_size; i++) {
- scale[i] = scale[j];
- j += jincr;
- }
- }
-}
-
-/**
* compute x^-0.25 with an exponent and mantissa table. We use linear
* interpolation to reduce the mantissa table size at a small speed
* expense (linear interpolation approximately doubles the number of
@@ -378,7 +349,7 @@ static void wma_window(WMACodecContext *
static int wma_decode_block(WMACodecContext *s)
{
int n, v, a, ch, code, bsize;
- int coef_nb_bits, total_gain, parse_exponents;
+ int coef_nb_bits, total_gain;
int nb_coefs[MAX_CHANNELS];
float mdct_norm;
@@ -493,13 +464,9 @@ static int wma_decode_block(WMACodecCont
}
}
- /* exposant can be interpolated in short blocks. */
- parse_exponents = 1;
- if (s->block_len_bits != s->frame_len_bits) {
- parse_exponents = get_bits(&s->gb, 1);
- }
-
- if (parse_exponents) {
+ /* exponents can be reused in short blocks. */
+ if ((s->block_len_bits == s->frame_len_bits) ||
+ get_bits(&s->gb, 1)) {
for(ch = 0; ch < s->nb_channels; ch++) {
if (s->channel_coded[ch]) {
if (s->use_exp_vlc) {
@@ -508,13 +475,7 @@ static int wma_decode_block(WMACodecCont
} else {
decode_exp_lsp(s, ch);
}
- }
- }
- } else {
- for(ch = 0; ch < s->nb_channels; ch++) {
- if (s->channel_coded[ch]) {
- interpolate_array(s->exponents[ch], 1 << s->prev_block_len_bits,
- s->block_len);
+ s->exponents_bsize[ch] = bsize;
}
}
}
@@ -588,12 +549,13 @@ static int wma_decode_block(WMACodecCont
for(ch = 0; ch < s->nb_channels; ch++) {
if (s->channel_coded[ch]) {
int16_t *coefs1;
- float *coefs, *exponents, mult, mult1, noise, *exp_ptr;
- int i, j, n, n1, last_high_band;
+ float *coefs, *exponents, mult, mult1, noise;
+ int i, j, n, n1, last_high_band, esize;
float exp_power[HIGH_BAND_MAX_SIZE];
coefs1 = s->coefs1[ch];
exponents = s->exponents[ch];
+ esize = s->exponents_bsize[ch];
mult = pow(10, total_gain * 0.05) / s->max_exponent[ch];
mult *= mdct_norm;
coefs = s->coefs[ch];
@@ -601,16 +563,16 @@ static int wma_decode_block(WMACodecCont
mult1 = mult;
/* very low freqs : noise */
for(i = 0;i < s->coefs_start; i++) {
- *coefs++ = s->noise_table[s->noise_index] * (*exponents++) * mult1;
+ *coefs++ = s->noise_table[s->noise_index] *
+ exponents[i<<bsize>>esize] * mult1;
s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
}
n1 = s->exponent_high_sizes[bsize];
/* compute power of high bands */
- exp_ptr = exponents +
- s->high_band_start[bsize] -
- s->coefs_start;
+ exponents = s->exponents[ch] +
+ (s->high_band_start[bsize]<<bsize);
last_high_band = 0; /* avoid warning */
for(j=0;j<n1;j++) {
n = s->exponent_high_bands[s->frame_len_bits -
@@ -619,17 +581,18 @@ static int wma_decode_block(WMACodecCont
float e2, v;
e2 = 0;
for(i = 0;i < n; i++) {
- v = exp_ptr[i];
+ v = exponents[i<<bsize>>esize];
e2 += v * v;
}
exp_power[j] = e2 / n;
last_high_band = j;
tprintf(s->avctx, "%d: power=%f (%d)\n", j, exp_power[j], n);
}
- exp_ptr += n;
+ exponents += n<<bsize;
}
/* main freqs and high freqs */
+ exponents = s->exponents[ch] + (s->coefs_start<<bsize);
for(j=-1;j<n1;j++) {
if (j < 0) {
n = s->high_band_start[bsize] -
@@ -648,21 +611,25 @@ static int wma_decode_block(WMACodecCont
for(i = 0;i < n; i++) {
noise = s->noise_table[s->noise_index];
s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
- *coefs++ = (*exponents++) * noise * mult1;
+ *coefs++ = noise *
+ exponents[i<<bsize>>esize] * mult1;
}
+ exponents += n<<bsize;
} else {
/* coded values + small noise */
for(i = 0;i < n; i++) {
noise = s->noise_table[s->noise_index];
s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
- *coefs++ = ((*coefs1++) + noise) * (*exponents++) * mult;
+ *coefs++ = ((*coefs1++) + noise) *
+ exponents[i<<bsize>>esize] * mult;
}
+ exponents += n<<bsize;
}
}
/* very high freqs : noise */
n = s->block_len - s->coefs_end[bsize];
- mult1 = mult * exponents[-1];
+ mult1 = mult * exponents[((-1<<bsize))>>esize];
for(i = 0; i < n; i++) {
*coefs++ = s->noise_table[s->noise_index] * mult1;
s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
@@ -673,7 +640,7 @@ static int wma_decode_block(WMACodecCont
*coefs++ = 0.0;
n = nb_coefs[ch];
for(i = 0;i < n; i++) {
- *coefs++ = coefs1[i] * exponents[i] * mult;
+ *coefs++ = coefs1[i] * exponents[i<<bsize>>esize] * mult;
}
n = s->block_len - s->coefs_end[bsize];
for(i = 0;i < n; i++)
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