diff options
Diffstat (limited to 'sbc/sbc_primitives.c')
| -rw-r--r-- | sbc/sbc_primitives.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/sbc/sbc_primitives.c b/sbc/sbc_primitives.c index 338feb96..303f3fee 100644 --- a/sbc/sbc_primitives.c +++ b/sbc/sbc_primitives.c @@ -401,6 +401,44 @@ static int sbc_enc_process_input_8s_be(int position, position, pcm, X, nsamples, 1, 1); } +/* Supplementary function to count the number of leading zeros */ + +static inline int sbc_clz(uint32_t x) +{ +#ifdef __GNUC__ + return __builtin_clz(x); +#else + /* TODO: this should be replaced with something better if good + * performance is wanted when using compilers other than gcc */ + int cnt = 0; + while (x) { + cnt++; + x >>= 1; + } + return 32 - cnt; +#endif +} + +static void sbc_calc_scalefactors( + int32_t sb_sample_f[16][2][8], + uint32_t scale_factor[2][8], + int blocks, int channels, int subbands) +{ + int ch, sb, blk; + for (ch = 0; ch < channels; ch++) { + for (sb = 0; sb < subbands; sb++) { + uint32_t x = 1 << SCALE_OUT_BITS; + for (blk = 0; blk < blocks; blk++) { + int32_t tmp = fabs(sb_sample_f[blk][ch][sb]); + if (tmp != 0) + x |= tmp - 1; + } + scale_factor[ch][sb] = (31 - SCALE_OUT_BITS) - + sbc_clz(x); + } + } +} + /* * Detect CPU features and setup function pointers */ @@ -416,6 +454,9 @@ void sbc_init_primitives(struct sbc_encoder_state *state) state->sbc_enc_process_input_8s_le = sbc_enc_process_input_8s_le; state->sbc_enc_process_input_8s_be = sbc_enc_process_input_8s_be; + /* Default implementation for scale factors calculation */ + state->sbc_calc_scalefactors = sbc_calc_scalefactors; + /* X86/AMD64 optimizations */ #ifdef SBC_BUILD_WITH_MMX_SUPPORT sbc_init_primitives_mmx(state); |