Fix a numerical overflow in wavegen() which could cause distortion when a voice file increases the height of formant peaks.

git-svn-id: https://espeak.svn.sourceforge.net/svnroot/espeak/trunk@92 d46cf337-b52f-0410-862d-fd96e6ae7743

src/Makefile

 LIBDIR=/usr/lib
 DATADIR=/usr/share/espeak-data
 
-RELEASE = 1.24
+RELEASE = 1.29
 BIN_NAME = speak
 BIN2_NAME = espeak
 LIB_NAME = libespeak.so

src/phonemelist.cpp

 	int regression;
 	int end_sourceix;
 	int alternative;
+	int first_vowel=0;   // first vowel in a word
 	PHONEME_LIST2 ph_list3[N_PHONEME_LIST];
 
 	static PHONEME_LIST2 ph_list2_null = {0,0,0,0,0};
 		// the last word is unstressed, look for a previous word that can be stressed
 		while(--j >= 0)
 		{
-			if(ph_list2[j].stress & 0x80)  // dictionary flags indicated that this stress can be promoted
+			if(ph_list2[j].synthflags & SFLAG_PROMOTE_STRESS)  // dictionary flags indicated that this stress can be promoted
 			{
 				ph_list2[j].stress = 4;   // promote to stressed
 				break;
 			}
-			if((ph_list2[j].stress & 0x7f) >= 4)
+			if(ph_list2[j].stress >= 4)
 			{
 				// found a stressed syllable, so stop looking
 				break;
 			// start of a word
 			int k;
 			word_stress = 0;
+			first_vowel = 1;
 
 			// find the highest stress level in this word
 			for(k=j+1; k < n_ph_list2; k++)
 					break;
 			}
 
+			if((stress_level == 1) && (first_vowel))
+				stress_level = 0;   // ignore 'dimished' stress on first syllable
+
 			if(stress_level == 1)
 				reduce = 1;    // stress = 'reduced'
 
 				break;
 		}
 
+		if(ph->type == phVOWEL)
+			first_vowel = 0;
+
 		if((plist2+1)->synthflags & SFLAG_LENGTHEN)
 		{
 			static char types_double[] = {phFRICATIVE,phVFRICATIVE,phNASAL,phLIQUID,0};
 
 		next2 = phoneme_tab[(plist2+2)->phcode];
 
-#ifdef deleted
-		if((ph->type != phVOWEL)  && (ph->type != phPAUSE)   //&& ((ph->phflags & phVOICED)==0)
-			&& (next->type == phLIQUID) && (next->mnemonic != ';') && (next2->type != phVOWEL))
-		{
-			// semi-vowel surrounded by consonants.  precede by a short schwa
-			insert_ph = phonSCHWA_SHORT;
-			insert_synthflags = SFLAG_SYLLABLE;
-		}
-
-		if((ph->type == phLIQUID) && (prev->type != phVOWEL) && (next->type != phVOWEL))
-		{
-			// semi-vowel surrounded by consonants.  precede by a short schwa
-			insert_ph = phonSCHWA_SHORT;
-			insert_synthflags = SFLAG_SYLLABLE;
-		}
-#endif
-
 		if((insert_ph == 0) && (ph->link_out != 0) && (((plist2+1)->synthflags & SFLAG_EMBEDDED)==0))
 		{
 			if(ph->phflags & phAPPENDPH)

src/synthesize.h

 #define SFLAG_LENGTHEN         0x08   // lengthen symbol : included after this phoneme
 #define SFLAG_DICTIONARY       0x10   // the pronunciation of this word was listed in the xx_list dictionary
 #define SFLAG_SWITCHED_LANG    0x20   // this word uses phonemes from a different language
-
+#define SFLAG_PROMOTE_STRESS   0x40   // this unstressed word can be promoted to stressed
 
 // embedded command numbers
 #define EMBED_P     1   // pitch

src/translate.cpp

 	if(flags & FLAG_STRESS_END2)
 	{
 		// this's word's stress could be increased later
-		ph_list2[max_stress_ix].stress |= 0x80;
+		ph_list2[max_stress_ix].synthflags |= SFLAG_PROMOTE_STRESS;
 	}
 
 	prev_dict_flags = flags;

src/wavegen.cpp

 			z2 = (z2 * mix_wave_amp)/32;
 		}
 
-		z1 = z2 + (((total>>7) * amplitude2) >> 14);
+		z1 = z2 + (((total>>8) * amplitude2) >> 13);
 
 		echo = (echo_buf[echo_tail++] * echo_amp);
 		z1 += echo >> 8;