# HG changeset patch # User Karl Tomlinson <karlt+@karlt.net> b=913854 add speex_resampler_set_skip_frac_num r=jmspeex This allows a client to align output samples consistently for independent resampling of contiguous input buffers. diff --git a/src/resample.c b/src/resample.c --- a/src/resample.c +++ b/src/resample.c @@ -1128,16 +1128,28 @@ EXPORT int speex_resampler_get_output_la EXPORT int speex_resampler_skip_zeros(SpeexResamplerState *st) { spx_uint32_t i; for (i=0;i<st->nb_channels;i++) st->last_sample[i] = st->filt_len/2; return RESAMPLER_ERR_SUCCESS; } +EXPORT int speex_resampler_set_skip_frac_num(SpeexResamplerState *st, spx_uint32_t skip_frac_num) +{ + spx_uint32_t i; + spx_uint32_t last_sample = skip_frac_num / st->den_rate; + spx_uint32_t samp_frac_num = skip_frac_num % st->den_rate; + for (i=0;i<st->nb_channels;i++) { + st->last_sample[i] = last_sample; + st->samp_frac_num[i] = samp_frac_num; + } + return RESAMPLER_ERR_SUCCESS; +} + EXPORT int speex_resampler_reset_mem(SpeexResamplerState *st) { spx_uint32_t i; for (i=0;i<st->nb_channels;i++) { st->last_sample[i] = 0; st->magic_samples[i] = 0; st->samp_frac_num[i] = 0; diff --git a/src/speex_resampler.h b/src/speex_resampler.h --- a/src/speex_resampler.h +++ b/src/speex_resampler.h @@ -69,16 +69,17 @@ #define speex_resampler_get_quality CAT_PREFIX(RANDOM_PREFIX,_resampler_get_quality) #define speex_resampler_set_input_stride CAT_PREFIX(RANDOM_PREFIX,_resampler_set_input_stride) #define speex_resampler_get_input_stride CAT_PREFIX(RANDOM_PREFIX,_resampler_get_input_stride) #define speex_resampler_set_output_stride CAT_PREFIX(RANDOM_PREFIX,_resampler_set_output_stride) #define speex_resampler_get_output_stride CAT_PREFIX(RANDOM_PREFIX,_resampler_get_output_stride) #define speex_resampler_get_input_latency CAT_PREFIX(RANDOM_PREFIX,_resampler_get_input_latency) #define speex_resampler_get_output_latency CAT_PREFIX(RANDOM_PREFIX,_resampler_get_output_latency) #define speex_resampler_skip_zeros CAT_PREFIX(RANDOM_PREFIX,_resampler_skip_zeros) +#define speex_resampler_set_skip_frac_num CAT_PREFIX(RANDOM_PREFIX,_resampler_set_skip_frac_num) #define speex_resampler_reset_mem CAT_PREFIX(RANDOM_PREFIX,_resampler_reset_mem) #define speex_resampler_strerror CAT_PREFIX(RANDOM_PREFIX,_resampler_strerror) #define spx_int16_t short #define spx_int32_t int #define spx_uint16_t unsigned short #define spx_uint32_t unsigned int @@ -317,16 +318,32 @@ int speex_resampler_get_output_latency(S * resampler. It is recommended to use that when resampling an audio file, as * it will generate a file with the same length. For real-time processing, * it is probably easier not to use this call (so that the output duration * is the same for the first frame). * @param st Resampler state */ int speex_resampler_skip_zeros(SpeexResamplerState *st); +/** Set the numerator in a fraction determining the advance through input + * samples before writing any output samples. The denominator of the fraction + * is the value returned from speex_resampler_get_ratio() in ratio_den. This + * is only useful before starting to use a newly created or reset resampler. + * If the first input sample is interpreted as the signal at time + * input_latency*in_rate, then the first output sample represents the signal + * at the time frac_num/ratio_num*out_rate. + * This is intended for careful alignment of output sample points wrt input + * sample points. Large values are not an efficient offset into the in buffer. + * @param st Resampler state + * @param skip_frac_num Numerator of the offset fraction, + * between 0 and ratio_den-1. + */ +int speex_resampler_set_skip_frac_num(SpeexResamplerState *st, + spx_uint32_t skip_frac_num); + /** Reset a resampler so a new (unrelated) stream can be processed. * @param st Resampler state */ int speex_resampler_reset_mem(SpeexResamplerState *st); /** Returns the English meaning for an error code * @param err Error code * @return English string