--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libgsmhr1/vad.h	Thu Mar 05 08:02:35 2026 +0000
@@ -0,0 +1,125 @@
+#ifndef __VAD
+#define __VAD
+
+#include "typedefs.h"
+
+
+/*_________________________________________________________________________
+ |                                                                         |
+ |                            Function Prototypes                          |
+ |_________________________________________________________________________|
+*/
+
+void   vad_reset(void);
+
+void   vad_algorithm
+       (
+               Longword pL_acf[9],
+               Shortword swScaleAcf,
+               Shortword pswRc[4],
+               Shortword swPtch,
+               Shortword *pswVadFlag
+);
+
+void   energy_computation
+       (
+               Longword pL_acf[],
+               Shortword swScaleAcf,
+               Shortword pswRvad[],
+               Shortword swNormRvad,
+               Shortword *pswM_pvad,
+               Shortword *pswE_pvad,
+               Shortword *pswM_acf0,
+               Shortword *pswE_acf0
+);
+
+
+void   average_acf
+       (
+               Longword pL_acf[],
+               Shortword swScaleAcf,
+               Longword pL_av0[],
+               Longword pL_av1[]
+);
+
+void   predictor_values
+       (
+               Longword pL_av1[],
+               Shortword pswRav1[],
+               Shortword *pswNormRav1
+);
+
+void   schur_recursion
+       (
+               Longword pL_av1[],
+               Shortword pswVpar[]
+);
+
+void   step_up
+       (
+               Shortword swNp,
+               Shortword pswVpar[],
+               Shortword pswAav1[]
+);
+
+void   compute_rav1
+       (
+               Shortword pswAav1[],
+               Shortword pswRav1[],
+               Shortword *pswNormRav1
+);
+
+void   spectral_comparison
+       (
+               Shortword pswRav1[],
+               Shortword swNormRav1,
+               Longword pL_av0[],
+               Shortword *pswStat
+);
+
+void   tone_detection
+       (
+               Shortword pswRc[4],
+               Shortword *pswTone
+);
+
+
+void   threshold_adaptation
+       (
+               Shortword swStat,
+               Shortword swPtch,
+               Shortword swTone,
+               Shortword pswRav1[],
+               Shortword swNormRav1,
+               Shortword swM_pvad,
+               Shortword swE_pvad,
+               Shortword swM_acf0,
+               Shortword swE_acf0,
+               Shortword pswRvad[],
+               Shortword *pswNormRvad,
+               Shortword *pswM_thvad,
+               Shortword *pswE_thvad
+);
+
+void   vad_decision
+       (
+               Shortword swM_pvad,
+               Shortword swE_pvad,
+               Shortword swM_thvad,
+               Shortword swE_thvad,
+               Shortword *pswVvad
+);
+
+void   vad_hangover
+       (
+               Shortword swVvad,
+               Shortword *pswVadFlag
+);
+
+void   periodicity_update
+       (
+               Shortword pswLags[4],
+               Shortword *pswPtch
+);
+
+#endif