diff --git a/libswresample/resample.c b/libswresample/resample.c index 868f3eb949..558401c459 100644 --- a/libswresample/resample.c +++ b/libswresample/resample.c @@ -367,3 +367,18 @@ int swri_multiple_resample(ResampleContext *c, AudioData *dst, int dst_size, Aud return ret; } + +int64_t swr_get_delay(struct SwrContext *s, int64_t base){ + ResampleContext *c = s->resample; + if(c){ + int64_t num = s->in_buffer_count - (c->filter_length-1)/2; + num <<= c->phase_shift; + num -= c->index; + num *= c->src_incr; + num -= c->frac; + + return av_rescale(num, base, s->in_sample_rate*(int64_t)c->src_incr << c->phase_shift); + }else{ + return (s->in_buffer_count*base + (s->in_sample_rate>>1))/ s->in_sample_rate; + } +} diff --git a/libswresample/swresample.h b/libswresample/swresample.h index 137517d6d2..43112f9c17 100644 --- a/libswresample/swresample.h +++ b/libswresample/swresample.h @@ -30,7 +30,7 @@ #include "libavutil/samplefmt.h" #define LIBSWRESAMPLE_VERSION_MAJOR 0 -#define LIBSWRESAMPLE_VERSION_MINOR 11 +#define LIBSWRESAMPLE_VERSION_MINOR 12 #define LIBSWRESAMPLE_VERSION_MICRO 100 #define LIBSWRESAMPLE_VERSION_INT AV_VERSION_INT(LIBSWRESAMPLE_VERSION_MAJOR, \ @@ -158,6 +158,24 @@ int swr_set_channel_mapping(struct SwrContext *s, const int *channel_map); */ int swr_set_matrix(struct SwrContext *s, const double *matrix, int stride); +/** + * Gets the delay the next input sample will experience relative to the next output sample. + * + * Swresample can buffer data if more input has been provided than available + * output space, also converting between sample rates needs a delay. + * This function returns the sum of all such delays. + * + * @param s swr context + * @param base timebase in which the returned delay will be + * if its set to 1 the returned delay is in seconds + * if its set to 1000 the returned delay is in milli seconds + * if its set to the input sample rate then the returned delay is in input samples + * if its set to the output sample rate then the returned delay is in output samples + * an exact rounding free delay can be found by using LCM(in_sample_rate, out_sample_rate) + * @returns the delay in 1/base units. + */ +int64_t swr_get_delay(struct SwrContext *s, int64_t base); + /** * Return the LIBSWRESAMPLE_VERSION_INT constant. */