ref: c1d40df49550393f3afe53fb6e6d500dfa8eb7a8
dir: /sys/src/cmd/audio/libvorbis/envelope.h/
/******************************************************************** * * * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE. * * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS * * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE * * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. * * * * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009 * * by the Xiph.Org Foundation https://xiph.org/ * * * ******************************************************************** function: PCM data envelope analysis and manipulation ********************************************************************/ #ifndef _V_ENVELOPE_ #define _V_ENVELOPE_ #include "mdct.h" #define VE_PRE 16 #define VE_WIN 4 #define VE_POST 2 #define VE_AMP (VE_PRE+VE_POST-1) #define VE_BANDS 7 #define VE_NEARDC 15 #define VE_MINSTRETCH 2 /* a bit less than short block */ #define VE_MAXSTRETCH 12 /* one-third full block */ typedef struct { float ampbuf[VE_AMP]; int ampptr; float nearDC[VE_NEARDC]; float nearDC_acc; float nearDC_partialacc; int nearptr; } envelope_filter_state; typedef struct { int begin; int end; float *window; float total; } envelope_band; typedef struct { int ch; int winlength; int searchstep; float minenergy; mdct_lookup mdct; float *mdct_win; envelope_band band[VE_BANDS]; envelope_filter_state *filter; int stretch; int *mark; long storage; long current; long curmark; long cursor; } envelope_lookup; extern void _ve_envelope_init(envelope_lookup *e,vorbis_info *vi); extern void _ve_envelope_clear(envelope_lookup *e); extern long _ve_envelope_search(vorbis_dsp_state *v); extern void _ve_envelope_shift(envelope_lookup *e,long shift); extern int _ve_envelope_mark(vorbis_dsp_state *v); #endif