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Better support for non-48 kHz sampling rates

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This commit is contained in:
Jean-Marc Valin 2010-07-16 11:47:50 -04:00
parent af1fce93b1
commit 223b69db02
2 changed files with 34 additions and 9 deletions
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2
libcelt/celt.c
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@ -508,7 +508,7 @@ void deemphasis(celt_sig *in, celt_word16 *pcm, int N, int _C, const celt_word16
celt_sig tmp = *x + m; celt_sig tmp = *x + m;
m = MULT16_32_Q15(coef[0], tmp) m = MULT16_32_Q15(coef[0], tmp)
- MULT16_32_Q15(coef[1], *x); - MULT16_32_Q15(coef[1], *x);
tmp = SHL32(MULT16_32_Q15(coef[3], tmp), 1); tmp = SHL32(MULT16_32_Q15(coef[3], tmp), 2);
*y = SCALEOUT(SIG2WORD16(tmp)); *y = SCALEOUT(SIG2WORD16(tmp));
x+=C; x+=C;
y+=C; y+=C;

41
libcelt/modes.c
View file

@ -314,16 +314,16 @@ CELTMode *celt_mode_create(celt_int32 Fs, int frame_size, int *error)
/* The good thing here is that permutation of the arguments will automatically be invalid */ /* The good thing here is that permutation of the arguments will automatically be invalid */
if (Fs < 32000 || Fs > 96000) if (Fs < 8000 || Fs > 96000)
{ {
celt_warning("Sampling rate must be between 32 kHz and 96 kHz"); celt_warning("Sampling rate must be between 8 kHz and 96 kHz");
if (error) if (error)
*error = CELT_BAD_ARG; *error = CELT_BAD_ARG;
return NULL; return NULL;
} }
if (frame_size < 64 || frame_size > 1024 || frame_size%2!=0) if (frame_size < 40 || frame_size > 1024 || frame_size%2!=0)
{ {
celt_warning("Only even frame sizes from 64 to 1024 are supported"); celt_warning("Only even frame sizes from 40 to 1024 are supported");
if (error) if (error)
*error = CELT_BAD_ARG; *error = CELT_BAD_ARG;
return NULL; return NULL;
@ -336,10 +336,35 @@ CELTMode *celt_mode_create(celt_int32 Fs, int frame_size, int *error)
mode->Fs = Fs; mode->Fs = Fs;
mode->ePredCoef = QCONST16(.8f,15); mode->ePredCoef = QCONST16(.8f,15);
mode->preemph[0] = QCONST16(.8, 15); /* Pre/de-emphasis depends on sampling rate. The "standard" pre-emphasis
mode->preemph[1] = QCONST16(.0, 15); is defined as A(z) = 1 - 0.85*z^-1 at 48 kHz. Other rates should
mode->preemph[2] = QCONST16(1., SIG_SHIFT); approximate that. */
mode->preemph[3] = QCONST16(1., 14); if(Fs < 12000) /* 8 kHz */
{
mode->preemph[0] = QCONST16(.35f, 15);
mode->preemph[1] = -QCONST16(.18f, 15);
mode->preemph[2] = QCONST16(.272f, SIG_SHIFT);
mode->preemph[3] = QCONST16(3.6765f, 13);
} else if(Fs < 24000) /* 16 kHz */
{
mode->preemph[0] = QCONST16(.6f, 15);
mode->preemph[1] = -QCONST16(.18f, 15);
mode->preemph[2] = QCONST16(.4425f, SIG_SHIFT);
mode->preemph[3] = QCONST16(2.259887f, 13);
} else if(Fs < 40000) /* 32 kHz */
{
mode->preemph[0] = QCONST16(.78f, 15);
mode->preemph[1] = -QCONST16(.1f, 15);
mode->preemph[2] = QCONST16(.75f, SIG_SHIFT);
mode->preemph[3] = QCONST16(1.33333333f, 13);
} else /* 48 kHz */
{
mode->preemph[0] = QCONST16(.85f, 15);
mode->preemph[1] = QCONST16(.0f, 15);
mode->preemph[2] = QCONST16(1.f, SIG_SHIFT);
mode->preemph[3] = QCONST16(1.f, 13);
}
if (frame_size >= 640 && (frame_size%16)==0) if (frame_size >= 640 && (frame_size%16)==0)
{ {
LM = 3; LM = 3;