AVResampleContext *swr_resample_init(AVResampleContext *c, int out_rate, int in_rate, int filter_size, int phase_shift, int linear, double cutoff){ double factor= FFMIN(out_rate * cutoff / in_rate, 1.0); int phase_count= 1<<phase_shift; if (!c || c->phase_shift != phase_shift || c->linear!=linear || c->factor != factor || c->filter_length != FFMAX((int)ceil(filter_size/factor), 1)) { c = av_mallocz(sizeof(AVResampleContext)); if (!c) return NULL; c->phase_shift = phase_shift; c->phase_mask = phase_count - 1; c->linear = linear; c->factor = factor; c->filter_length = FFMAX((int)ceil(filter_size/factor), 1); c->filter_bank = av_mallocz(c->filter_length*(phase_count+1)*sizeof(FELEM)); if (!c->filter_bank) goto error; if (build_filter(c->filter_bank, factor, c->filter_length, phase_count, 1<<FILTER_SHIFT, WINDOW_TYPE)) goto error; memcpy(&c->filter_bank[c->filter_length*phase_count+1], c->filter_bank, (c->filter_length-1)*sizeof(FELEM)); c->filter_bank[c->filter_length*phase_count]= c->filter_bank[c->filter_length - 1]; } c->compensation_distance= 0; c->src_incr= out_rate; c->ideal_dst_incr= c->dst_incr= in_rate * phase_count; c->index= -phase_count*((c->filter_length-1)/2); c->frac= 0; return c; error: av_free(c->filter_bank); av_free(c); return NULL; }