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authorMichael Niedermayer <michaelni@gmx.at>2013-10-15 20:06:44 +0200
committerMichael Niedermayer <michaelni@gmx.at>2013-10-15 21:03:03 +0200
commit59352a07d856a67b81fe3480ac4644a92beac113 (patch)
treee3ba1af18e69daf1f9842bf6df3de3736d9704a1 /libavcodec/mpegaudio_tablegen.h
parente51692114354b8e460bf5c9f6def7089a6b969c0 (diff)
avcodec: improve precission for cbrtf() emulation
cbrtf() took floats but it represented 1/3 exactly and even if not more precission should be better in theory for the table generation Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Diffstat (limited to 'libavcodec/mpegaudio_tablegen.h')
-rw-r--r--libavcodec/mpegaudio_tablegen.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/libavcodec/mpegaudio_tablegen.h b/libavcodec/mpegaudio_tablegen.h
index 1e1a38296b..60303b16ad 100644
--- a/libavcodec/mpegaudio_tablegen.h
+++ b/libavcodec/mpegaudio_tablegen.h
@@ -49,7 +49,7 @@ static void mpegaudio_tableinit(void)
double f, fm;
int e, m;
/* cbrtf() isn't available on all systems, so we use powf(). */
- f = value / IMDCT_SCALAR * powf(value, 1.0 / 3.0) * pow(2, (i & 3) * 0.25);
+ f = value / IMDCT_SCALAR * pow(value, 1.0 / 3.0) * pow(2, (i & 3) * 0.25);
fm = frexp(f, &e);
m = (uint32_t)(fm * (1LL << 31) + 0.5);
e += FRAC_BITS - 31 + 5 - 100;
@@ -61,7 +61,7 @@ static void mpegaudio_tableinit(void)
for (exponent = 0; exponent < 512; exponent++) {
for (value = 0; value < 16; value++) {
/* cbrtf() isn't available on all systems, so we use powf(). */
- double f = (double)value * powf(value, 1.0 / 3.0) * pow(2, (exponent - 400) * 0.25 + FRAC_BITS + 5) / IMDCT_SCALAR;
+ double f = (double)value * pow(value, 1.0 / 3.0) * pow(2, (exponent - 400) * 0.25 + FRAC_BITS + 5) / IMDCT_SCALAR;
/* llrint() isn't always available, so round and cast manually. */
expval_table_fixed[exponent][value] = (long long int) (f >= 0 ? floor(f + 0.5) : ceil(f - 0.5));
expval_table_float[exponent][value] = f;