| /* $Id$ */ |
| /* |
| * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com) |
| * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org> |
| * |
| * 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 |
| */ |
| #ifndef __PJMEDIA_WSOLA_H__ |
| #define __PJMEDIA_WSOLA_H__ |
| |
| /** |
| * @file wsola.h |
| * @brief Waveform Similarity Based Overlap-Add (WSOLA) |
| */ |
| #include <pjmedia/types.h> |
| |
| /** |
| * @defgroup PJMED_WSOLA Waveform Similarity Based Overlap-Add (WSOLA) |
| * @ingroup PJMEDIA_FRAME_OP |
| * @brief Time-scale modification to audio without affecting the pitch |
| * @{ |
| * |
| * This section describes Waveform Similarity Based Overlap-Add (WSOLA) |
| * implementation in PJMEDIA. The WSOLA API here can be used both to |
| * compress (speed-up) and stretch (expand, slow down) audio playback |
| * without altering the pitch, or as a mean for performing packet loss |
| * concealment (WSOLA). |
| * |
| * The WSOLA implementation is used by \ref PJMED_DELAYBUF and \ref PJMED_PLC. |
| */ |
| |
| PJ_BEGIN_DECL |
| |
| |
| /** |
| * Opaque declaration for WSOLA structure. |
| */ |
| typedef struct pjmedia_wsola pjmedia_wsola; |
| |
| |
| /** |
| * WSOLA options, can be combined with bitmask operation. |
| */ |
| enum pjmedia_wsola_option |
| { |
| /** |
| * Disable Hanning window to conserve memory. |
| */ |
| PJMEDIA_WSOLA_NO_HANNING = 1, |
| |
| /** |
| * Specify that the WSOLA will not be used for PLC. |
| */ |
| PJMEDIA_WSOLA_NO_PLC = 2, |
| |
| /** |
| * Specify that the WSOLA will not be used to discard frames in |
| * non-contiguous buffer. |
| */ |
| PJMEDIA_WSOLA_NO_DISCARD = 4, |
| |
| /** |
| * Disable fade-in and fade-out feature in the transition between |
| * actual and synthetic frames in WSOLA. With fade feature enabled, |
| * WSOLA will only generate a limited number of synthetic frames |
| * (configurable with #pjmedia_wsola_set_max_expand()), fading out |
| * the volume on every more samples it generates, and when it reaches |
| * the limit it will only generate silence. |
| */ |
| PJMEDIA_WSOLA_NO_FADING = 8 |
| }; |
| |
| |
| |
| /** |
| * Create and initialize WSOLA. |
| * |
| * @param pool Pool to allocate memory for WSOLA. |
| * @param clock_rate Sampling rate of audio playback. |
| * @param samples_per_frame Number of samples per frame. |
| * @param channel_count Number of channels. |
| * @param options Option flags, bitmask combination of |
| * #pjmedia_wsola_option. |
| * @param p_wsola Pointer to receive WSOLA structure. |
| * |
| * @return PJ_SUCCESS or the appropriate error code. |
| */ |
| PJ_DECL(pj_status_t) pjmedia_wsola_create(pj_pool_t *pool, |
| unsigned clock_rate, |
| unsigned samples_per_frame, |
| unsigned channel_count, |
| unsigned options, |
| pjmedia_wsola **p_wsola); |
| |
| |
| /** |
| * Specify maximum number of continuous synthetic frames that can be |
| * generated by WSOLA, in milliseconds. This option will only take |
| * effect if fading is not disabled via the option when the WSOLA |
| * session was created. Default value is PJMEDIA_WSOLA_MAX_EXPAND_MSEC |
| * (see also the documentation of PJMEDIA_WSOLA_MAX_EXPAND_MSEC for |
| * more information). |
| * |
| * @param wsola The WSOLA session |
| * @param msec The duration. |
| * |
| * @return PJ_SUCCESS normally. |
| */ |
| PJ_DECL(pj_status_t) pjmedia_wsola_set_max_expand(pjmedia_wsola *wsola, |
| unsigned msec); |
| |
| |
| /** |
| * Destroy WSOLA. |
| * |
| * @param wsola WSOLA session. |
| * |
| * @return PJ_SUCCESS normally. |
| */ |
| PJ_DECL(pj_status_t) pjmedia_wsola_destroy(pjmedia_wsola *wsola); |
| |
| |
| /** |
| * Reset the buffer contents of WSOLA. |
| * |
| * @param wsola WSOLA session. |
| * @param options Reset options, must be zero for now. |
| * |
| * @return PJ_SUCCESS normally. |
| */ |
| PJ_DECL(pj_status_t) pjmedia_wsola_reset(pjmedia_wsola *wsola, |
| unsigned options); |
| |
| |
| /** |
| * Give one good frame to WSOLA to be kept as reference. Application |
| * must continuously give WSOLA good frames to keep its session up to |
| * date with current playback. Depending on the WSOLA implementation, |
| * this function may modify the content of the frame. |
| * |
| * @param wsola WSOLA session. |
| * @param frm The frame, which length must match the samples per |
| * frame setting of the WSOLA session. |
| * @param prev_lost If application previously generated a synthetic |
| * frame with #pjmedia_wsola_generate() before calling |
| * this function, specify whether that was because of |
| * packet lost. If so, set this parameter to PJ_TRUE |
| * to make WSOLA interpolate this frame with its buffer. |
| * Otherwise if this value is PJ_FALSE, WSOLA will |
| * just append this frame to the end of its buffer. |
| * |
| * @return PJ_SUCCESS normally. |
| */ |
| PJ_DECL(pj_status_t) pjmedia_wsola_save(pjmedia_wsola *wsola, |
| pj_int16_t frm[], |
| pj_bool_t prev_lost); |
| |
| /** |
| * Generate one synthetic frame from WSOLA. |
| * |
| * @param wsola WSOLA session. |
| * @param frm Buffer to receive the frame. |
| * |
| * @return PJ_SUCCESS normally. |
| */ |
| PJ_DECL(pj_status_t) pjmedia_wsola_generate(pjmedia_wsola *wsola, |
| pj_int16_t frm[]); |
| |
| |
| /** |
| * Compress or compact the specified buffer by removing some audio samples |
| * from the buffer, without altering the pitch. For this function to work, |
| * total length of the buffer must be more than twice \a erase_cnt. |
| * |
| * @param wsola WSOLA session. |
| * @param buf1 Pointer to buffer. |
| * @param buf1_cnt Number of samples in the buffer. |
| * @param buf2 Pointer to second buffer, if the buffer is not |
| * contiguous. Otherwise this parameter must be NULL. |
| * @param buf2_cnt Number of samples in the second buffer, if the buffer |
| * is not contiguous. Otherwise this parameter should be |
| * zero. |
| * @param erase_cnt On input, specify the number of samples to be erased. |
| * This function may erase more or less than the requested |
| * number, and the actual number of samples erased will be |
| * given on this argument upon returning from the function. |
| * |
| * @return PJ_SUCCESS if some samples have been erased, PJ_ETOOSMALL |
| * if buffer is too small to be reduced, PJ_EINVAL if any |
| * of the parameters are not valid. |
| */ |
| PJ_DECL(pj_status_t) pjmedia_wsola_discard(pjmedia_wsola *wsola, |
| pj_int16_t buf1[], |
| unsigned buf1_cnt, |
| pj_int16_t buf2[], |
| unsigned buf2_cnt, |
| unsigned *erase_cnt); |
| |
| |
| PJ_END_DECL |
| |
| /** |
| * @} |
| */ |
| |
| #endif /* __PJMEDIA_WSOLA_H__ */ |
| |