/* $Id$ */ /* * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com) * Copyright (C) 2003-2008 Benny Prijono * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include #include #if PJMEDIA_RESAMPLE_IMP==PJMEDIA_RESAMPLE_LIBRESAMPLE #include #define THIS_FILE "resample.c" struct pjmedia_resample { double factor; /* Conversion factor = rate_out / rate_in. */ pj_bool_t large_filter; /* Large filter? */ pj_bool_t high_quality; /* Not fast? */ unsigned xoff; /* History and lookahead size, in samples */ unsigned frame_size; /* Samples per frame. */ unsigned channel_cnt; /* Channel count. */ /* Buffer for monochannel */ pj_int16_t *buffer; /* Input buffer. */ /* Buffer for multichannel */ pj_int16_t **in_buffer; /* Array of input buffer for each channel. */ pj_int16_t *tmp_buffer; /* Temporary output buffer for processing. */ }; PJ_DEF(pj_status_t) pjmedia_resample_create( pj_pool_t *pool, pj_bool_t high_quality, pj_bool_t large_filter, unsigned channel_count, unsigned rate_in, unsigned rate_out, unsigned samples_per_frame, pjmedia_resample **p_resample) { pjmedia_resample *resample; PJ_ASSERT_RETURN(pool && p_resample && rate_in && rate_out && samples_per_frame, PJ_EINVAL); resample = PJ_POOL_ZALLOC_T(pool, pjmedia_resample); PJ_ASSERT_RETURN(resample, PJ_ENOMEM); /* * If we're downsampling, always use the fast algorithm since it seems * to yield the same quality. */ if (rate_out < rate_in) { //no this is not a good idea. It sounds pretty good with speech, //but very poor with background noise etc. //high_quality = 0; } resample->factor = rate_out * 1.0 / rate_in; resample->large_filter = large_filter; resample->high_quality = high_quality; resample->channel_cnt = channel_count; resample->frame_size = samples_per_frame; if (high_quality) { /* This is a bug in xoff calculation, thanks Stephane Lussier * of Macadamian dot com. * resample->xoff = large_filter ? 32 : 6; */ resample->xoff = res_GetXOFF(resample->factor, (char)large_filter); } else { resample->xoff = 1; } if (channel_count == 1) { unsigned size; /* Allocate input buffer */ size = (samples_per_frame + 2*resample->xoff) * sizeof(pj_int16_t); resample->buffer = (pj_int16_t*) pj_pool_alloc(pool, size); PJ_ASSERT_RETURN(resample->buffer, PJ_ENOMEM); pjmedia_zero_samples(resample->buffer, resample->xoff*2); } else if (channel_count > 1) { unsigned i, size; /* Allocate input buffer table */ size = channel_count * sizeof(pj_int16_t*); resample->in_buffer = (pj_int16_t**)pj_pool_alloc(pool, size); /* Allocate input buffer */ size = (samples_per_frame/channel_count + 2*resample->xoff) * sizeof(pj_int16_t); for (i = 0; i < channel_count; ++i) { resample->in_buffer[i] = (pj_int16_t*)pj_pool_alloc(pool, size); PJ_ASSERT_RETURN(resample->in_buffer, PJ_ENOMEM); pjmedia_zero_samples(resample->in_buffer[i], resample->xoff*2); } /* Allocate temporary output buffer */ size = (unsigned) (resample->frame_size * sizeof(pj_int16_t) * resample->factor / channel_count + 0.5); resample->tmp_buffer = (pj_int16_t*) pj_pool_alloc(pool, size); PJ_ASSERT_RETURN(resample->tmp_buffer, PJ_ENOMEM); } *p_resample = resample; PJ_LOG(5,(THIS_FILE, "resample created: %s qualiy, %s filter, in/out " "rate=%d/%d", (high_quality?"high":"low"), (large_filter?"large":"small"), rate_in, rate_out)); return PJ_SUCCESS; } PJ_DEF(void) pjmedia_resample_run( pjmedia_resample *resample, const pj_int16_t *input, pj_int16_t *output ) { PJ_ASSERT_ON_FAIL(resample, return); /* Okay chaps, here's how we do resampling. * * The original resample algorithm requires xoff samples *before* the * input buffer as history, and another xoff samples *after* the * end of the input buffer as lookahead. Since application can only * supply framesize buffer on each run, PJMEDIA needs to arrange the * buffer to meet these requirements. * * So here comes the trick. * * First of all, because of the history and lookahead requirement, * resample->buffer need to accomodate framesize+2*xoff samples in its * buffer. This is done when the buffer is created. * * On the first run, the input frame (supplied by application) is * copied to resample->buffer at 2*xoff position. The first 2*xoff * samples are initially zeroed (in the initialization). The resample * algorithm then invoked at resample->buffer+xoff ONLY, thus giving * it one xoff at the beginning as zero, and one xoff at the end * as the end of the original input. The resample algorithm will see * that the first xoff samples in the input as zero. * * So here's the layout of resample->buffer on the first run. * * run 0 * +------+------+--------------+ * | 0000 | 0000 | frame0... | * +------+------+--------------+ * ^ ^ ^ ^ * 0 xoff 2*xoff size+2*xoff * * (Note again: resample algorithm is called at resample->buffer+xoff) * * At the end of the run, 2*xoff samples from the end of * resample->buffer are copied to the beginning of resample->buffer. * The first xoff part of this will be used as history for the next * run, and the second xoff part of this is actually the start of * resampling for the next run. * * And the first run completes, the function returns. * * * On the next run, the input frame supplied by application is again * copied at 2*xoff position in the resample->buffer, and the * resample algorithm is again invoked at resample->buffer+xoff * position. So effectively, the resample algorithm will start its * operation on the last xoff from the previous frame, and gets the * history from the last 2*xoff of the previous frame, and the look- * ahead from the last xoff of current frame. * * So on this run, the buffer layout is: * * run 1 * +------+------+--------------+ * | frm0 | frm0 | frame1... | * +------+------+--------------+ * ^ ^ ^ ^ * 0 xoff 2*xoff size+2*xoff * * As you can see from above diagram, the resampling algorithm is * actually called from the last xoff part of previous frame (frm0). * * And so on the process continues for the next frame, and the next, * and the next, ... * */ if (resample->channel_cnt == 1) { pj_int16_t *dst_buf; const pj_int16_t *src_buf; /* Prepare input frame */ dst_buf = resample->buffer + resample->xoff*2; pjmedia_copy_samples(dst_buf, input, resample->frame_size); /* Resample */ if (resample->high_quality) { res_Resample(resample->buffer + resample->xoff, output, resample->factor, (pj_uint16_t)resample->frame_size, (char)resample->large_filter, (char)PJ_TRUE); } else { res_SrcLinear(resample->buffer + resample->xoff, output, resample->factor, (pj_uint16_t)resample->frame_size); } /* Update history */ dst_buf = resample->buffer; src_buf = input + resample->frame_size - resample->xoff*2; pjmedia_copy_samples(dst_buf, src_buf, resample->xoff * 2); } else { /* Multichannel */ unsigned i, j; for (i = 0; i < resample->channel_cnt; ++i) { pj_int16_t *dst_buf; const pj_int16_t *src_buf; unsigned mono_frm_sz_in; unsigned mono_frm_sz_out; mono_frm_sz_in = resample->frame_size / resample->channel_cnt; mono_frm_sz_out = (unsigned)(mono_frm_sz_in * resample->factor + 0.5); /* Deinterleave input */ dst_buf = resample->in_buffer[i] + resample->xoff*2; src_buf = input + i; for (j = 0; j < mono_frm_sz_in; ++j) { *dst_buf++ = *src_buf; src_buf += resample->channel_cnt; } /* Resample this channel */ if (resample->high_quality) { res_Resample(resample->in_buffer[i] + resample->xoff, resample->tmp_buffer, resample->factor, (pj_uint16_t)mono_frm_sz_in, (char)resample->large_filter, (char)PJ_TRUE); } else { res_SrcLinear( resample->in_buffer[i], resample->tmp_buffer, resample->factor, (pj_uint16_t)mono_frm_sz_in); } /* Update history */ dst_buf = resample->in_buffer[i]; src_buf = resample->in_buffer[i] + mono_frm_sz_in; pjmedia_copy_samples(dst_buf, src_buf, resample->xoff * 2); /* Reinterleave output */ dst_buf = output + i; src_buf = resample->tmp_buffer; for (j = 0; j < mono_frm_sz_out; ++j) { *dst_buf = *src_buf++; dst_buf += resample->channel_cnt; } } } } PJ_DEF(unsigned) pjmedia_resample_get_input_size(pjmedia_resample *resample) { PJ_ASSERT_RETURN(resample != NULL, 0); return resample->frame_size; } PJ_DEF(void) pjmedia_resample_destroy(pjmedia_resample *resample) { PJ_UNUSED_ARG(resample); } #elif PJMEDIA_RESAMPLE_IMP==PJMEDIA_RESAMPLE_NONE /* * This is the configuration when sample rate conversion is disabled. */ PJ_DEF(pj_status_t) pjmedia_resample_create( pj_pool_t *pool, pj_bool_t high_quality, pj_bool_t large_filter, unsigned channel_count, unsigned rate_in, unsigned rate_out, unsigned samples_per_frame, pjmedia_resample **p_resample) { PJ_UNUSED_ARG(pool); PJ_UNUSED_ARG(high_quality); PJ_UNUSED_ARG(large_filter); PJ_UNUSED_ARG(channel_count); PJ_UNUSED_ARG(rate_in); PJ_UNUSED_ARG(rate_out); PJ_UNUSED_ARG(samples_per_frame); PJ_UNUSED_ARG(p_resample); return PJ_EINVALIDOP; } PJ_DEF(void) pjmedia_resample_run( pjmedia_resample *resample, const pj_int16_t *input, pj_int16_t *output ) { PJ_UNUSED_ARG(resample); PJ_UNUSED_ARG(input); PJ_UNUSED_ARG(output); } PJ_DEF(unsigned) pjmedia_resample_get_input_size(pjmedia_resample *resample) { PJ_UNUSED_ARG(resample); return 0; } PJ_DEF(void) pjmedia_resample_destroy(pjmedia_resample *resample) { PJ_UNUSED_ARG(resample); } #endif /* PJMEDIA_RESAMPLE_IMP */