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Correctly implement remaining portions of ffmpeg's r8627 that I'd forgotten about. This fixes a table overflow in low bitrate files that use noise coding, and in theory should be substantial improvement, but I haven't found any files were it makes a difference.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@19500 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Michael Giacomelli 2008-12-20 05:43:58 +00:00
parent 7a0baa3aa5
commit 2557251351
1 changed files with 14 additions and 18 deletions
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32
apps/codecs/libwma/wmadeci.c
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@ -1195,13 +1195,13 @@ static int wma_decode_block(WMADecodeContext *s, int32_t *scratch_buffer)
}
/* finally compute the MDCT coefficients */
/* finally compute the MDCT coefficients */
for(ch = 0; ch < s->nb_channels; ++ch)
{
if (s->channel_coded[ch])
{
int16_t *coefs1;
fixed32 *exponents, *exp_ptr;
fixed32 *exponents;
fixed32 *coefs, atemp;
fixed64 mult;
fixed64 mult1;
@ -1215,7 +1215,6 @@ static int wma_decode_block(WMADecodeContext *s, int32_t *scratch_buffer)
exponents = s->exponents[ch];
esize = s->exponents_bsize[ch];
coefs = (*(s->coefs))[ch];
n=0;
/*
@ -1237,16 +1236,14 @@ static int wma_decode_block(WMADecodeContext *s, int32_t *scratch_buffer)
/* very low freqs : noise */
for(i = 0;i < s->coefs_start; ++i)
{
*coefs++ = fixmul32( (fixmul32(s->noise_table[s->noise_index],(*exponents++))>>4),Fixed32From64(mult1)) >>2;
*coefs++ = fixmul32( (fixmul32(s->noise_table[s->noise_index],exponents[i<<bsize>>esize])>>4),Fixed32From64(mult1)) >>2;
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)
{
@ -1259,16 +1256,17 @@ static int wma_decode_block(WMADecodeContext *s, int32_t *scratch_buffer)
for(i = 0;i < n; ++i)
{
/*v is noramlized later on so its fixed format is irrelevant*/
v = exp_ptr[i]>>4;
v = exponents[i<<bsize>>esize]>>4;
e2 += fixmul32(v, v)>>3;
}
exp_power[j] = e2/n; /*n is an int...*/
last_high_band = j;
}
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)
@ -1287,40 +1285,38 @@ static int wma_decode_block(WMADecodeContext *s, int32_t *scratch_buffer)
fixed32 tmp = fixdiv32(exp_power[j],exp_power[last_high_band]);
/*mult1 is 48.16, pow_table is 48.16*/
mult1 = fixmul32(fixsqrt32(tmp),pow_table[s->high_band_values[ch][j]+20]) >> 16;
/*this step has a fairly high degree of error for some reason*/
mult1 = fixdiv64(mult1,fixmul32(s->max_exponent[ch],s->noise_mult));
mult1 = fixdiv64(mult1,fixmul32(s->max_exponent[ch],s->noise_mult));
mult1 = mult1*mdct_norm>>PRECISION;
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++ = fixmul32((fixmul32(*exponents,noise)>>4),Fixed32From64(mult1)) >>2;
++exponents;
*coefs++ = fixmul32((fixmul32(exponents[i<<bsize>>esize],noise)>>4),Fixed32From64(mult1)) >>2;
}
exponents += n<<bsize;
}
else
{
/* coded values + small noise */
for(i = 0;i < n; ++i)
{
// PJJ: check code path
noise = s->noise_table[s->noise_index];
s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
/*don't forget to renormalize the noise*/
temp1 = (((int32_t)*coefs1++)<<16) + (noise>>4);
temp2 = fixmul32(*exponents, mult>>18);
temp2 = fixmul32(exponents[i<<bsize>>esize], mult>>18);
*coefs++ = fixmul32(temp1, temp2);
++exponents;
}
exponents += n<<bsize;
}
}
/* very high freqs : noise */
n = s->block_len - s->coefs_end[bsize];
mult2 = fixmul32(mult>>16,exponents[-1]) ; /*the work around for 32.32 vars are getting stupid*/
mult2 = fixmul32(mult>>16,exponents[((-1<<bsize))>>esize]) ; /*the work around for 32.32 vars are getting stupid*/
for (i = 0; i < n; ++i)
{
/*renormalize the noise product and then reduce to 14.18 precison*/