optimised build, VBR fix, debug strip

CMakeLists.txt

@@ -8,9 +8,10 @@ function(em_file name)
             ${CMAKE_SOURCE_DIR}/decoder.cpp
             ${CMAKE_SOURCE_DIR}/${name}.cpp
             -o ${CMAKE_BINARY_DIR}/${name}.js 
-            -s WASM=0
-            -g4
-            -s TOTAL_MEMORY=64MB
+            -s FILESYSTEM=0
+            -s ENVIRONMENT=web
+            -Oz
+            --llvm-lto 1
             )
 endfunction(em_file)
 

decoder.cpp

@@ -2,27 +2,30 @@
 #include <iostream>
 
 Decoder::Decoder():
+state(empty),
 sampleRate(0),
 channels(0),
 cachedLength(0),
 samplesPerFrame(0),
-buffer(new uint8_t[BUFFER_LENGTH]),
+glue(new uint8_t[GLUE_LENGTH]),
+cachedNext(NULL),
+cachedThis(NULL),
+cachedError(MAD_ERROR_NONE),
 cached(false),
 synth(new mad_synth()),
 stream(new mad_stream()),
 frame(new mad_frame()),
-context(0)
+context(0),
+pending()
 {
-    for (int i = 0; i < BUFFER_LENGTH; ++i) {
-        buffer[i] = 0;
+    for (int i = 0; i < GLUE_LENGTH; ++i) {
+        glue[i] = 0;
     }
     
     mad_frame_init(frame);
     mad_stream_init(stream);
     mad_synth_init(synth);
     
-    mad_stream_buffer(stream, buffer, 0);
-    
     emscripten::val AudioContext = emscripten::val::global("AudioContext");
     if (!AudioContext.as<bool>()) {
         AudioContext = emscripten::val::global("webkitAudioContext");
@@ -43,23 +46,58 @@ Decoder::~Decoder()
     delete stream;
     delete frame;
     
-    delete[] buffer;
+    delete[] glue;
 }
 
-void Decoder::addFragment(intptr_t bufferPtr, uint32_t length)
+void Decoder::addFragment(const emscripten::val& array)
 {
-    std::cout << "Adding new fragment " << length << " bytes long" << std::endl;
-    uint8_t* bf = (uint8_t(*))bufferPtr;
-    uint64_t ol = stream->bufend - stream->buffer;
+    uint32_t length = array["length"].as<uint32_t>();
+    
+    if (length < GLUE_LENGTH / 2) {
+        std::cout << "Error: an attempt to add fragment smaller then half of the glue buffer, ignoring";
+        return;
+    }
+    uint8_t* buffer = new uint8_t[length];
     
     for (int i = 0; i < length; ++i) {
-        buffer[ol + i] = bf[i];
+        buffer[i] = array[std::to_string(i)].as<uint8_t>();
     }
-    //free(bf);
     
-    stream->bufend = stream->bufend + length;
-    cached = false;
-    framesLeft();
+    RawBuffer rb = {buffer, length};
+    pending.push_back(rb);
+    
+    switch (state) {
+        case empty:
+            mad_stream_buffer(stream, buffer, length);
+            
+            for (int i = 0; i < GLUE_LENGTH/2; ++i) {
+                glue[i] = buffer[length - GLUE_LENGTH/2 + i];
+            }
+            
+            state = onBufferHalf;
+            prepareNextBuffer();
+            break;
+        case onBufferHalf:
+            for (int i = 0; i < GLUE_LENGTH/2; ++i) {
+                glue[GLUE_LENGTH/2 + i] = buffer[i];
+            }
+            
+            state = onBufferFull;
+            break;
+        case onBufferFull:
+            break;
+        case onGlueHalf:
+            for (int i = 0; i < GLUE_LENGTH/2; ++i) {
+                glue[GLUE_LENGTH/2 + i] = buffer[i];
+            }
+            
+            state = onGlueFull;
+            cached = false;
+            prepareNextBuffer();
+            break;
+        case onGlueFull:
+            break;
+    }
 }
 
 emscripten::val Decoder::decode(uint32_t count)
@@ -76,12 +114,10 @@ emscripten::val Decoder::decode(uint32_t count)
             chans[i] = ret.call<emscripten::val>("getChannelData", i);
         } 
         
-        for (int i = 0; i < available; ++i) {
+        for (int i = 0; success < available; ++i) {
             int res = mad_frame_decode(frame, stream);
             
-            if (res == 0) {
-                ++success;
-            } else {
+            if (res != 0) {
                 if (MAD_RECOVERABLE(stream->error)) {
                     
                     std::cout << "Unexpected error during the decoding process: " << mad_stream_errorstr(stream) << std::endl;
@@ -96,16 +132,19 @@ emscripten::val Decoder::decode(uint32_t count)
             for (int j = 0; j < samplesPerFrame; ++j) {
                 for (int k = 0; k < channels; ++k) {
                     float value = mad_f_todouble(synth->pcm.samples[k][j]);
-                    chans[k].set(std::to_string(i * samplesPerFrame + j), emscripten::val(value));
+                    chans[k].set(std::to_string(success * samplesPerFrame + j), emscripten::val(value));
                 }
             }
+            ++success;
         }
         
         cachedLength -= available;
+        #if DEBUGGING
         std::cout << "Processed " << available << " frames, " << success << " successfully, last error " << mad_stream_errorstr(stream) << std::endl;
-        
+        #endif
         if (cachedLength == 0) {
-            framesLeft();
+            cached = false;
+            prepareNextBuffer();
         }
     }
     
@@ -114,64 +153,144 @@ emscripten::val Decoder::decode(uint32_t count)
 
 bool Decoder::hasMore() const
 {
-    return stream->bufend != stream->buffer && stream->error != MAD_ERROR_BUFLEN;
+    if (pending.size() == 1) {
+        return stream->error != MAD_ERROR_BUFLEN;
+    } else {
+        return true;
+    }
 }
 
 uint32_t Decoder::framesLeft(uint32_t max)
 {
-    if (!hasMore()) {
+    if (state == empty || state == onGlueHalf) {
         return 0;
     }
     
     if (cached == false) {
-        bool found = false;
         mad_stream probe;
         mad_header ph;
         initializeProbe(probe);
         mad_header_init(&ph);
+        sampleRate = 0;
         
         while (cachedLength < max) {
             if (mad_header_decode(&ph, &probe) == 0) {
-                found = true;
                 if (sampleRate == 0) {
                     sampleRate = ph.samplerate;
                     channels = MAD_NCHANNELS(&ph);
                     samplesPerFrame = MAD_NSBSAMPLES(&ph) * 32; //not sure why 32, it's in libmad source
                 } else {
                     if (sampleRate != ph.samplerate || channels != MAD_NCHANNELS(&ph) || samplesPerFrame != MAD_NSBSAMPLES(&ph) * 32) {
-                        break;
+                        if (cachedLength > 0) {
+                            #if DEBUGGING
+                            std::cout << "sample rate " << sampleRate << " -> " << ph.samplerate << std::endl;
+                            std::cout << "channels " << channels << " -> " << MAD_NCHANNELS(&ph) << std::endl;
+                            std::cout << "samples per frame " << samplesPerFrame << " -> " << MAD_NSBSAMPLES(&ph) * 32 << std::endl;
+                            #endif
+                            probe.next_frame = probe.this_frame;
+                            break;
+                        }
                     }
                 }
                 if (probe.next_frame > probe.this_frame) {
                     ++cachedLength;
                 }
             } else {
-                if (!found) {
-                    stream->next_frame = probe.next_frame;
-                }
+                #if DEBUGGING
                 std::cout << "framesLeft error: " << mad_stream_errorstr(&probe) << std::endl;
+                #endif
                 if (!MAD_RECOVERABLE(probe.error)) {
                     break;
                 }
             }
         }
         
+        cachedNext = probe.next_frame;
+        cachedThis = probe.this_frame;
+        cachedError = probe.error;
         mad_header_finish(&ph);
         mad_stream_finish(&probe);
+        #if DEBUGGING
         std::cout << cachedLength << " frames are available for decoding" << std::endl;
+        #endif
         cached = true;
     }
     
     return std::min(cachedLength, max);
 }
 
+void Decoder::pullBuffer()
+{
+    if (cached == false) {
+        std::cout << "Error in pullBuffer method!" << std::endl;
+    }
+    stream->this_frame = cachedThis;
+    stream->next_frame = cachedNext;
+    stream->error = cachedError;
+}
+
+void Decoder::changeBuffer()
+{
+    switch (state) {
+        case empty:
+            std::cout << "Wrong state on switchBuffer method - empty, aborting" << std::endl;
+        case onBufferHalf:
+            switchToGlue();
+            state = onGlueHalf;
+            break;
+        case onBufferFull:
+            switchToGlue();
+            state = onGlueFull;
+            break;
+        case onGlueHalf:
+            std::cout << "Wrong state on switchBuffer method - onGlueHalf, aborting" << std::endl;
+            break;
+        case onGlueFull:
+            #if DEBUGGING
+            std::cout << "Having another fragment " << pending[0].length << " bytes long" << std::endl;
+            #endif
+            
+            switchBuffer(pending[0].ptr, pending[0].length);
+            
+            for (int i = 0; i < GLUE_LENGTH/2; ++i) {
+                glue[i] = pending[0].ptr[pending[0].length - GLUE_LENGTH/2 + i];
+            }
+            
+            state = onBufferHalf;
+            
+            if (pending.size() > 1) {
+                for (int i = 0; i < GLUE_LENGTH/2; ++i) {
+                    glue[GLUE_LENGTH/2 + i] = pending[1].ptr[i];
+                }
+                
+                state = onBufferFull;
+            }
+    }
+    
+    cached = false;
+}
+
+void Decoder::prepareNextBuffer()
+{
+    bool shift;
+    do {
+        shift = false;
+        framesLeft();
+        if (cachedLength == 0 && state != empty && state != onGlueHalf) {
+            pullBuffer();
+            changeBuffer();
+            shift = true;
+        }
+    } while (shift);
+}
+
 void Decoder::initializeProbe(mad_stream& probe)
 {
     mad_stream_init(&probe);
     
     probe.buffer = stream->buffer;
     probe.bufend = stream->bufend;
-    //probe.skiplen = stream->skiplen; 
+    probe.skiplen = stream->skiplen; 
     //probe.sync = stream->sync;
     //probe.freerate = stream->freerate;
     //probe.this_frame = stream->this_frame;
@@ -188,3 +307,41 @@ void Decoder::initializeProbe(mad_stream& probe)
     //probe.options = stream->options;
     //probe.error = stream->error;
 }
+
+void Decoder::switchToGlue()
+{
+    #if DEBUGGING
+    std::cout << "Switching to glue" << std::endl;
+    #endif
+    switchBuffer(glue, GLUE_LENGTH);
+    
+    #if DEBUGGING
+    std::cout << "Freeing the drained fragment" << std::endl;
+    #endif
+    delete[] pending[0].ptr;
+    pending.pop_front();
+}
+
+void Decoder::switchBuffer(uint8_t* bufferPtr, uint32_t length)
+{
+    uint32_t left;
+    
+    if (stream->error != MAD_ERROR_BUFLEN) {
+        std::cout << "WARNING: Switching buffers while the previous one is not drained, last error: " << mad_stream_errorstr(stream) << std::endl;
+    }
+    if (stream->next_frame != NULL) {
+        left = stream->bufend - stream->next_frame;
+    } else {
+        std::cout << "WARNING: not supposed to happen" << std::endl;
+    }
+    
+    if (left > GLUE_LENGTH / 2) {
+        std::cout << "Error: bytes to read in the buffer are more then glue buffer can fit (" << left << ")" << std::endl;
+        throw 1;
+    }
+    
+    mad_stream_buffer(stream, bufferPtr + GLUE_LENGTH / 2 - left, length - (GLUE_LENGTH / 2 - left));
+    stream->error = MAD_ERROR_NONE;
+    
+    while (mad_header_decode(&frame->header, stream) != 0 && stream->error != MAD_ERROR_BUFLEN) {}
+}

decoder.h

@@ -9,24 +9,43 @@
 #include <emscripten/val.h>
 #include "mad.h"
 
-#define BUFFER_LENGTH 30000000
+#define GLUE_LENGTH 6000
 
 class Decoder {
 public:
     Decoder();
     ~Decoder();
     
-    void addFragment(intptr_t bufferPtr, uint32_t length);
+    void addFragment(const emscripten::val& array);
     emscripten::val decode(uint32_t count = UINT32_MAX);
     bool hasMore() const;
     uint32_t framesLeft(uint32_t max = UINT32_MAX);
     
 private:
+    
+    enum State {
+        empty,
+        onBufferHalf,
+        onBufferFull,
+        onGlueHalf,
+        onGlueFull
+    };
+    
+    struct RawBuffer {
+        uint8_t* ptr;
+        uint32_t length;
+    };
+    
+    State state;
+    
     uint32_t sampleRate;
     uint8_t channels;
     uint32_t cachedLength;
     uint16_t samplesPerFrame;
-    uint8_t* buffer;
+    uint8_t* glue;
+    uint8_t const* cachedNext;
+    uint8_t const* cachedThis;
+    mad_error cachedError;
     bool cached;
     
     mad_synth* synth;
@@ -34,9 +53,15 @@ private:
     mad_frame* frame;
     emscripten::val context;
     
+    std::deque<RawBuffer> pending;
+    
 private:
+    void pullBuffer();
+    void changeBuffer();
+    void prepareNextBuffer();
     void initializeProbe(mad_stream& probe);
-
+    void switchToGlue();
+    void switchBuffer(uint8_t* bufferPtr, uint32_t length);
 };
 
 #endif // DECODER_H

index.html

@@ -12,14 +12,13 @@
   <script src="wrapper.js"></script>
     <input type="file" id="file" name="file" />
   <script>
-    var minPortion = 60000;
-    var maxPortion = 100000;
+    var minPortion = 4096;
+    var maxPortion = 40960;
     var time = 0;
     var ctx = new AudioContext();
     ctx.suspend();
     var decoder;
     var fragments = [];
-    var noize = [];
     var decoding = false;
     function onChange(e) {
         var file = e.target.files[0];
@@ -51,21 +50,20 @@
                 setTimeout(schedule, Math.floor(audio.duration * 200));
                 decoding = true;
             } else {
-                //decoder.delete();
+                decoder.delete();
             }
         } else {
-            //decoder.delete();
+            decoder.delete();
         }
     }
     
     function scheduleData() {
         if (fragments.length) {
             var frag = fragments.shift();
-            
-            decoder.addFragment(frag.ptr, frag.length);
+            decoder.addFragment(frag);
             
             if (fragments.length) {
-                setTimeout(scheduleData, 50);
+                setTimeout(scheduleData, 100);
             }
             
             if (!decoding) {
@@ -80,20 +78,10 @@
         
         while (shoved !== src.length) {
             var ps = Math.min(Math.floor(Math.random() * (maxPortion - minPortion) + minPortion), src.length - shoved);
-            var ptr = Module._malloc(ps);
             
-            var arr = new Uint8Array(Module.HEAPU8.buffer, ptr, ps);
             var portion = new Uint8Array(buffer, shoved, ps)
-            arr.set(portion, 0);
-            
             shoved += ps;
-            
-            fragments.push({
-                ptr: ptr,
-                length: ps
-            });
-            
-            noize.push(Module._malloc(256));
+            fragments.push(portion);
         }
     }