diff options
-rw-r--r-- | celt/celt_decoder.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/celt/celt_decoder.c b/celt/celt_decoder.c index 43b876b8..e441d045 100644 --- a/celt/celt_decoder.c +++ b/celt/celt_decoder.c @@ -177,6 +177,36 @@ void opus_custom_decoder_destroy(CELTDecoder *st) } #endif /* CUSTOM_MODES */ +#ifndef CUSTOM_MODES +/* Special case for stereo with no downsampling and no accumulation. This is + quite common and we can make it faster by processing both channels in the + same loop, reducing overhead due to the dependency loop in the IIR filter. */ +static void deemphasis_stereo_simple(celt_sig *in[], opus_val16 *pcm, int N, const opus_val16 coef0, + celt_sig *mem) +{ + celt_sig * OPUS_RESTRICT x0; + celt_sig * OPUS_RESTRICT x1; + celt_sig m0, m1; + int j; + x0=in[0]; + x1=in[1]; + m0 = mem[0]; + m1 = mem[1]; + for (j=0;j<N;j++) + { + celt_sig tmp0, tmp1; + /* Add VERY_SMALL to x[] first to reduce dependency chain. */ + tmp0 = x0[j] + VERY_SMALL + m0; + tmp1 = x1[j] + VERY_SMALL + m1; + m0 = MULT16_32_Q15(coef0, tmp0); + m1 = MULT16_32_Q15(coef0, tmp1); + pcm[2*j ] = SCALEOUT(SIG2WORD16(tmp0)); + pcm[2*j+1] = SCALEOUT(SIG2WORD16(tmp1)); + } + mem[0] = m0; + mem[1] = m1; +} +#endif #ifndef RESYNTH static @@ -190,6 +220,14 @@ void deemphasis(celt_sig *in[], opus_val16 *pcm, int N, int C, int downsample, c opus_val16 coef0; VARDECL(celt_sig, scratch); SAVE_STACK; +#ifndef CUSTOM_MODES + /* Short version for common case. */ + if (downsample == 1 && C == 2 && !accum) + { + deemphasis_stereo_simple(in, pcm, N, coef[0], mem); + return; + } +#endif #ifndef FIXED_POINT (void)accum; celt_assert(accum==0); |