ac3.js - npm Package Compare versions

Comparing version 0.2.2 to 0.2.3

lib/audioblock.js

@@ -82,2 +82,6 @@ 'use strict';
             }
+        } else {
+            for (var _ch3 = 0; _ch3 < bsi.nfchans; _ch3++) {
+                audblk.chincpl[_ch3] = 0;
+            }
         }
@@ -88,14 +92,14 @@ }
     if (audblk.cplinu) {
-        for (var _ch3 = 0; _ch3 < bsi.nfchans; _ch3++) {
-            if (audblk.chincpl[_ch3]) {
-                audblk.cplcoe[_ch3] = stream.read(1);
-                if (audblk.cplcoe[_ch3]) {
-                    audblk.mstrcplco[_ch3] = stream.read(2);
+        for (var _ch4 = 0; _ch4 < bsi.nfchans; _ch4++) {
+            if (audblk.chincpl[_ch4]) {
+                audblk.cplcoe[_ch4] = stream.read(1);
+                if (audblk.cplcoe[_ch4]) {
+                    audblk.mstrcplco[_ch4] = stream.read(2);
 
-                    audblk.cplcoexp[_ch3] = new Array(audblk.ncplbnd);
-                    audblk.cplcomant[_ch3] = new Array(audblk.ncplbnd);
-                    audblk.cplco[_ch3] = new Array(audblk.ncplbnd);
+                    audblk.cplcoexp[_ch4] = new Array(audblk.ncplbnd);
+                    audblk.cplcomant[_ch4] = new Array(audblk.ncplbnd);
+                    audblk.cplco[_ch4] = new Array(audblk.ncplbnd);
                     for (var _bnd2 = 0; _bnd2 < audblk.ncplbnd; _bnd2++) {
-                        audblk.cplcoexp[_ch3][_bnd2] = stream.read(4);
-                        audblk.cplcomant[_ch3][_bnd2] = stream.read(4);
+                        audblk.cplcoexp[_ch4][_bnd2] = stream.read(4);
+                        audblk.cplcomant[_ch4][_bnd2] = stream.read(4);
                     }
@@ -108,10 +112,10 @@ }
                     if (!audblk.cplbndstrc[sbnd]) {
-                        if (audblk.cplcoexp[_ch3][_bnd] === 15) {
-                            cplco = audblk.cplcomant[_ch3][_bnd] / 16;
+                        if (audblk.cplcoexp[_ch4][_bnd] === 15) {
+                            cplco = audblk.cplcomant[_ch4][_bnd] / 16;
                         } else {
-                            cplco = (audblk.cplcomant[_ch3][_bnd] + 16) / 32;
+                            cplco = (audblk.cplcomant[_ch4][_bnd] + 16) / 32;
                         }
-                        cplco /= Math.pow(2, audblk.cplcoexp[_ch3][_bnd] + 3 * audblk.mstrcplco[_ch3]);
+                        cplco /= Math.pow(2, audblk.cplcoexp[_ch4][_bnd] + 3 * audblk.mstrcplco[_ch4]);
                     }
-                    audblk.cplco[_ch3][sbnd] = cplco;
+                    audblk.cplco[_ch4][sbnd] = cplco;
                 }
@@ -154,4 +158,4 @@ }
 
-    for (var _ch4 = 0; _ch4 < bsi.nfchans; _ch4++) {
-        audblk.chexpstr[_ch4] = stream.read(2);
+    for (var _ch5 = 0; _ch5 < bsi.nfchans; _ch5++) {
+        audblk.chexpstr[_ch5] = stream.read(2);
     }
@@ -163,6 +167,6 @@
 
-    for (var _ch5 = 0; _ch5 < bsi.nfchans; _ch5++) {
-        if (audblk.chexpstr[_ch5] !== _constants.EXP_REUSE) {
-            if (!audblk.chincpl[_ch5]) {
-                audblk.chbwcod[_ch5] = stream.read(6);
+    for (var _ch6 = 0; _ch6 < bsi.nfchans; _ch6++) {
+        if (audblk.chexpstr[_ch6] !== _constants.EXP_REUSE) {
+            if (!audblk.chincpl[_ch6]) {
+                audblk.chbwcod[_ch6] = stream.read(6);
             }
@@ -202,33 +206,33 @@ }
     // Exponents for full bandwidth channels
-    for (var _ch6 = 0; _ch6 < bsi.nfchans; _ch6++) {
-        if (audblk.chexpstr[_ch6] !== _constants.EXP_REUSE) {
-            audblk.strtmant[_ch6] = 0;
-            if (audblk.chincpl[_ch6]) {
-                audblk.endmant[_ch6] = 37 + 12 * audblk.cplbegf;
+    for (var _ch7 = 0; _ch7 < bsi.nfchans; _ch7++) {
+        if (audblk.chexpstr[_ch7] !== _constants.EXP_REUSE) {
+            audblk.strtmant[_ch7] = 0;
+            if (audblk.chincpl[_ch7]) {
+                audblk.endmant[_ch7] = 37 + 12 * audblk.cplbegf;
             } else {
-                audblk.endmant[_ch6] = 37 + 3 * (audblk.chbwcod[_ch6] + 12);
+                audblk.endmant[_ch7] = 37 + 3 * (audblk.chbwcod[_ch7] + 12);
             }
 
-            switch (audblk.chexpstr[_ch6]) {
+            switch (audblk.chexpstr[_ch7]) {
                 case _constants.EXP_D15:
-                    audblk.nchgrps[_ch6] = (audblk.endmant[_ch6] - 1) / 3 >> 0;
+                    audblk.nchgrps[_ch7] = (audblk.endmant[_ch7] - 1) / 3 >> 0;
                     break;
                 case _constants.EXP_D25:
-                    audblk.nchgrps[_ch6] = (audblk.endmant[_ch6] + 2) / 6 >> 0;
+                    audblk.nchgrps[_ch7] = (audblk.endmant[_ch7] + 2) / 6 >> 0;
                     break;
                 case _constants.EXP_D45:
-                    audblk.nchgrps[_ch6] = (audblk.endmant[_ch6] + 8) / 12 >> 0;
+                    audblk.nchgrps[_ch7] = (audblk.endmant[_ch7] + 8) / 12 >> 0;
                     break;
             }
 
-            audblk.exps[_ch6] = new Array(audblk.nchgrps[_ch6]);
+            audblk.exps[_ch7] = new Array(audblk.nchgrps[_ch7]);
             var absexps = stream.read(4);
-            for (var _grp = 0; _grp < audblk.nchgrps[_ch6]; _grp++) {
-                audblk.exps[_ch6][_grp] = stream.read(7);
+            for (var _grp = 0; _grp < audblk.nchgrps[_ch7]; _grp++) {
+                audblk.exps[_ch7][_grp] = stream.read(7);
             }
 
             // Unpack exponent groups
-            audblk.exps[_ch6] = (0, _exponents.unpackExponents)(audblk.exps[_ch6], absexps, _constants.EXPONENT_GROUP_SIZE[audblk.chexpstr[_ch6]], 1);
+            audblk.exps[_ch7] = (0, _exponents.unpackExponents)(audblk.exps[_ch7], absexps, _constants.EXPONENT_GROUP_SIZE[audblk.chexpstr[_ch7]], 1);
 
-            audblk.gainrng[_ch6] = stream.read(2);
+            audblk.gainrng[_ch7] = stream.read(2);
         }
@@ -274,5 +278,5 @@ }
         audblk.fgaincod = new Array(bsi.nfchans);
-        for (var _ch7 = 0; _ch7 < bsi.nfchans; _ch7++) {
-            audblk.fsnroffst[_ch7] = stream.read(4);
-            audblk.fgaincod[_ch7] = stream.read(3);
+        for (var _ch8 = 0; _ch8 < bsi.nfchans; _ch8++) {
+            audblk.fsnroffst[_ch8] = stream.read(4);
+            audblk.fgaincod[_ch8] = stream.read(3);
         }
@@ -300,4 +304,4 @@
 
-        for (var _ch8 = 0; _ch8 < bsi.nfchans; _ch8++) {
-            audblk.deltbae[_ch8] = stream.read(2);
+        for (var _ch9 = 0; _ch9 < bsi.nfchans; _ch9++) {
+            audblk.deltbae[_ch9] = stream.read(2);
         }
@@ -324,13 +328,13 @@
         audblk.deltnseg = new Array(bsi.nfchans);
-        for (var _ch9 = 0; _ch9 < bsi.nfchans; _ch9++) {
-            if (audblk.deltbae[_ch9] === 0x1) {
-                audblk.deltnseg[_ch9] = stream.read(2);
+        for (var _ch10 = 0; _ch10 < bsi.nfchans; _ch10++) {
+            if (audblk.deltbae[_ch10] === 0x1) {
+                audblk.deltnseg[_ch10] = stream.read(2);
 
-                audblk.deltoffst[_ch9] = new Array(audblk.deltnseg[_ch9] + 1);
-                audblk.deltlen[_ch9] = new Array(audblk.deltnseg[_ch9] + 1);
-                audblk.deltba[_ch9] = new Array(audblk.deltnseg[_ch9] + 1);
-                for (var _seg = 0; _seg <= audblk.deltnseg[_ch9]; _seg++) {
-                    audblk.deltoffst[_ch9][_seg] = stream.read(5);
-                    audblk.deltlen[_ch9][_seg] = stream.read(4);
-                    audblk.deltba[_ch9][_seg] = stream.read(3);
+                audblk.deltoffst[_ch10] = new Array(audblk.deltnseg[_ch10] + 1);
+                audblk.deltlen[_ch10] = new Array(audblk.deltnseg[_ch10] + 1);
+                audblk.deltba[_ch10] = new Array(audblk.deltnseg[_ch10] + 1);
+                for (var _seg = 0; _seg <= audblk.deltnseg[_ch10]; _seg++) {
+                    audblk.deltoffst[_ch10][_seg] = stream.read(5);
+                    audblk.deltlen[_ch10][_seg] = stream.read(4);
+                    audblk.deltba[_ch10][_seg] = stream.read(3);
                 }
@@ -341,4 +345,4 @@ }
         audblk.cpldeltbae = 2;
-        for (var _ch10 = 0; _ch10 < bsi.nfchans; _ch10++) {
-            audblk.deltbae[_ch10] = 2;
+        for (var _ch11 = 0; _ch11 < bsi.nfchans; _ch11++) {
+            audblk.deltbae[_ch11] = 2;
         }
@@ -354,13 +358,13 @@ }
     audblk.baps = new Array(bsi.nfchans);
-    for (var _ch11 = 0; _ch11 < bsi.nfchans; _ch11++) {
+    for (var _ch12 = 0; _ch12 < bsi.nfchans; _ch12++) {
         var delt = null;
-        if (audblk.deltbae[_ch11] == 0 || audblk.deltbae[_ch11] == 1) {
+        if (audblk.deltbae[_ch12] == 0 || audblk.deltbae[_ch12] == 1) {
             delt = {
-                nseg: audblk.deltnseg[_ch11],
-                offst: audblk.deltoffst[_ch11],
-                ba: audblk.deltba[_ch11],
-                len: audblk.deltlen[_ch11]
+                nseg: audblk.deltnseg[_ch12],
+                offst: audblk.deltoffst[_ch12],
+                ba: audblk.deltba[_ch12],
+                len: audblk.deltlen[_ch12]
             };
         }
-        audblk.baps[_ch11] = (0, _bitallocation.bitAllocation)(bsi, audblk, audblk.strtmant[_ch11], audblk.endmant[_ch11], audblk.exps[_ch11], _tables.FAST_GAIN[audblk.fgaincod[_ch11]], (audblk.csnroffst - 15 << 4) + audblk.fsnroffst[_ch11] << 2, 0, 0, delt);
+        audblk.baps[_ch12] = (0, _bitallocation.bitAllocation)(bsi, audblk, audblk.strtmant[_ch12], audblk.endmant[_ch12], audblk.exps[_ch12], _tables.FAST_GAIN[audblk.fgaincod[_ch12]], (audblk.csnroffst - 15 << 4) + audblk.fsnroffst[_ch12] << 2, 0, 0, delt);
     }
@@ -395,14 +399,14 @@ if (audblk.cplinu) {
     audblk.chmant = new Array(bsi.nfchans);
-    for (var _ch12 = 0; _ch12 < bsi.nfchans; _ch12++) {
-        audblk.chmant[_ch12] = new Array(256);
-        audblk.chmant[_ch12].fill(0);
-        for (var bin = 0; bin < audblk.endmant[_ch12]; bin++) {
-            if (audblk.baps[_ch12][bin] != 0 || !audblk.dithflag[_ch12]) {
-                audblk.chmant[_ch12][bin] = mantissas.get(audblk.baps[_ch12][bin]) * Math.pow(2, -audblk.exps[_ch12][bin]);
+    for (var _ch13 = 0; _ch13 < bsi.nfchans; _ch13++) {
+        audblk.chmant[_ch13] = new Array(256);
+        audblk.chmant[_ch13].fill(0);
+        for (var bin = 0; bin < audblk.endmant[_ch13]; bin++) {
+            if (audblk.baps[_ch13][bin] != 0 || !audblk.dithflag[_ch13]) {
+                audblk.chmant[_ch13][bin] = mantissas.get(audblk.baps[_ch13][bin]) * Math.pow(2, -audblk.exps[_ch13][bin]);
             } else {
-                audblk.chmant[_ch12][bin] = (0, _mantissa.getDitherMantissa)() * Math.pow(2, -audblk.exps[_ch12][bin]);
+                audblk.chmant[_ch13][bin] = (0, _mantissa.getDitherMantissa)() * Math.pow(2, -audblk.exps[_ch13][bin]);
             }
         }
 
-        if (audblk.cplinu && audblk.chincpl[_ch12] && !audblk.got_cplchan) {
+        if (audblk.cplinu && audblk.chincpl[_ch13] && !audblk.got_cplchan) {
             audblk.ncplmant = 12 * audblk.ncplsubnd;
@@ -427,8 +431,8 @@ audblk.cplmant = new Array(audblk.ncplmant);
     if (audblk.cplinu) {
-        for (var _ch13 = 0; _ch13 < bsi.nfchans; _ch13++) {
-            if (audblk.chincpl[_ch13]) {
+        for (var _ch14 = 0; _ch14 < bsi.nfchans; _ch14++) {
+            if (audblk.chincpl[_ch14]) {
                 for (var _sbnd = 0; _sbnd < audblk.ncplsubnd; _sbnd++) {
                     for (var _bin3 = 0; _bin3 < 12; _bin3++) {
                         var mantissa = void 0;
-                        if (audblk.cplmant[_sbnd * 12 + _bin3] == 0 && audblk.dithflag[_ch13]) {
+                        if (audblk.cplmant[_sbnd * 12 + _bin3] == 0 && audblk.dithflag[_ch14]) {
                             mantissa = (0, _mantissa.getDitherMantissa)() * Math.pow(2, -audblk.cplexps[_sbnd * 12 + _bin3]);
@@ -438,3 +442,3 @@ } else {
                         }
-                        audblk.chmant[_ch13][(_sbnd + audblk.cplbegf) * 12 + _bin3 + 37] = mantissa * audblk.cplco[_ch13][_sbnd] * 8;
+                        audblk.chmant[_ch14][(_sbnd + audblk.cplbegf) * 12 + _bin3 + 37] = mantissa * audblk.cplco[_ch14][_sbnd] * 8;
                     }
@@ -462,7 +466,7 @@ }
 
-    for (var _ch14 = 0; _ch14 < bsi.nfchans; _ch14++) {
-        if (audblk.blksw[_ch14]) {
-            imdct[_ch14].process128(audblk.chmant[_ch14], samples[_ch14], blk * 256);
+    for (var _ch15 = 0; _ch15 < bsi.nfchans; _ch15++) {
+        if (audblk.blksw[_ch15]) {
+            imdct[_ch15].process128(audblk.chmant[_ch15], samples[_ch15], blk * 256);
         } else {
-            imdct[_ch14].process256(audblk.chmant[_ch14], samples[_ch14], blk * 256);
+            imdct[_ch15].process256(audblk.chmant[_ch15], samples[_ch15], blk * 256);
         }
@@ -469,0 +473,0 @@ }

lib/decoder.js

@@ -53,2 +53,4 @@ 'use strict';
         _this.pcm = false;
+        _this.samples = null;
+        _this.imdct = null;
 
@@ -78,8 +80,16 @@ _this.pcm = pcm;
             // Intialize arrays
-            var samples = new Array(bsi.nfchans);
-            var imdct = new Array(bsi.nfchans);
-            for (var i = 0; i < bsi.nfchans; i++) {
-                samples[i] = new Array(_constants.AUDIO_SAMPLES);
-                imdct[i] = new _mdct.IMDCT();
+            // IMDCT instances must be preserved across chunks for proper decoding.
+            // Otherwise, overlapping samples will be lost.
+            if (!this.samples) {
+                this.samples = new Array(bsi.nfchans);
+                for (var i = 0; i < bsi.nfchans; i++) {
+                    this.samples[i] = new Array(_constants.AUDIO_SAMPLES);
+                }
             }
+            if (!this.imdct) {
+                this.imdct = new Array(bsi.nfchans);
+                for (var _i = 0; _i < bsi.nfchans; _i++) {
+                    this.imdct[_i] = new _mdct.IMDCT();
+                }
+            }
 
@@ -89,7 +99,7 @@ // Audio Blocks
             for (var blk = 0; blk < 6; blk++) {
-                (0, _audioblock.readAudioBlock)(this.bitstream, bsi, samples, imdct, audblk, blk);
+                (0, _audioblock.readAudioBlock)(this.bitstream, bsi, this.samples, this.imdct, audblk, blk);
             }
 
             // Downmixing
-            (0, _downmix.downmix)(bsi, samples);
+            (0, _downmix.downmix)(bsi, this.samples);
 
@@ -104,10 +114,10 @@ // Skip auxiliary data
                 var sample = void 0;
-                for (var _i = 0; _i < _constants.AUDIO_SAMPLES; _i++) {
-                    sample = samples[0][_i] * 65535;
-                    sampleBytes[_i * 4] = sample & 0xff;
-                    sampleBytes[_i * 4 + 1] = sample >> 8;
+                for (var _i2 = 0; _i2 < _constants.AUDIO_SAMPLES; _i2++) {
+                    sample = this.samples[0][_i2] * 65535;
+                    sampleBytes[_i2 * 4] = sample & 0xff;
+                    sampleBytes[_i2 * 4 + 1] = sample >> 8;
 
-                    sample = samples[1][_i] * 65535;
-                    sampleBytes[_i * 4 + 2] = sample & 0xff;
-                    sampleBytes[_i * 4 + 3] = sample >> 8;
+                    sample = this.samples[1][_i2] * 65535;
+                    sampleBytes[_i2 * 4 + 2] = sample & 0xff;
+                    sampleBytes[_i2 * 4 + 3] = sample >> 8;
                 }
@@ -120,6 +130,6 @@
                 var _sample = void 0;
-                for (var _i2 = 0; _i2 < _constants.AUDIO_SAMPLES; _i2++) {
+                for (var _i3 = 0; _i3 < _constants.AUDIO_SAMPLES; _i3++) {
                     for (var ch = 0; ch < CHANNELS; ch++) {
-                        _sample = samples[ch][_i2] * 65535;
-                        result[ch + _i2 * 2] = _sample;
+                        _sample = this.samples[ch][_i3] * 65535;
+                        result[ch + _i3 * 2] = _sample;
                     }
@@ -126,0 +136,0 @@ }

package.json

 {
   "name": "ac3.js",
   "description": "JavaScript AC-3 (ATSC A/52) decoder",
-  "version": "0.2.2",
+  "version": "0.2.3",
   "license": "MIT",
@@ -6,0 +6,0 @@ "contributors": [

No alert changes

Improved metrics

Total package byte prevSize

472195

0.33%

Lines of code

2556

0.55%

No dependency changes