Basic decoding with edge effects

CMakeLists.txt

@@ -1,8 +1,11 @@
 cmake_minimum_required(VERSION 3.0)
+
+set(EMO libmad.bc)
 function(em_file name)
     execute_process(COMMAND
         emcc --bind 
             ${CMAKE_SOURCE_DIR}/libmad.bc
+            ${CMAKE_SOURCE_DIR}/decoder.cpp
             ${CMAKE_SOURCE_DIR}/${name}.cpp
             -o ${CMAKE_BINARY_DIR}/${name}.js 
             -s WASM=0
@@ -13,3 +16,4 @@ endfunction(em_file)
 configure_file(index.html index.html)
 
 em_file(wrapper)
+

decoder.cpp

@@ -0,0 +1,362 @@
+#include "decoder.h"
+#include <iostream>
+
+Decoder::Decoder():
+state(empty),
+sampleRate(0),
+channels(0),
+cachedLength(0),
+samplesPerFrame(0),
+glue(new uint8_t[GLUE_LENGTH]),
+lastSync(-1),
+cached(false),
+synth(),
+stream(),
+frame(),
+context(0),
+pending()
+{
+    for (int i = 0; i < GLUE_LENGTH; ++i) {
+        glue[i] = 0;
+    }
+    
+    mad_frame_init(&frame);
+    mad_stream_init(&stream);
+    mad_synth_init(&synth);
+    
+    emscripten::val AudioContext = emscripten::val::global("AudioContext");
+    if (!AudioContext.as<bool>()) {
+        AudioContext = emscripten::val::global("webkitAudioContext");
+    }
+    
+    context = AudioContext.new_();
+}
+
+Decoder::~Decoder()
+{
+    context.call<void>("close");
+    
+    mad_synth_finish(&synth);
+    mad_stream_finish(&stream);
+    mad_frame_finish(&frame);
+    
+    delete[] glue;
+}
+
+void Decoder::addFragment(intptr_t bufferPtr, uint32_t length)
+{
+    if (length < GLUE_LENGTH / 2) {
+        std::cout << "An attempt to add fragment smaller then half of the glue buffer, ignoring";
+        return;
+    }
+    std::cout << "Adding new fragment " << length << " bytes long" << std::endl;
+    uint8_t* buffer = (uint8_t(*))bufferPtr;
+    RawBuffer rb = {buffer, length, 0, 0};
+    pending.push_back(rb);
+    
+    std::cout << "The state now is " << state << std::endl;
+    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)
+{
+    emscripten::val ret = emscripten::val::undefined();
+    
+    int available = framesLeft(count);
+    int success = 0;
+    if (available > 0) {
+        ret = context.call<emscripten::val>("createBuffer", channels, available * samplesPerFrame, sampleRate);
+        
+        std::vector<emscripten::val> chans(channels, emscripten::val::undefined());
+        for (int i = 0; i < channels; ++i) {
+            chans[i] = ret.call<emscripten::val>("getChannelData", i);
+        } 
+        
+        for (int i = 0; success < available; ++i) {
+            int res = mad_frame_decode(&frame, &stream);
+            
+            if (res == 0) {
+                lastSync = stream.bufend - stream.this_frame;
+                ++success;
+            } else {
+                if (MAD_RECOVERABLE(stream.error)) {
+                    
+                    std::cout << "Unexpected error during the decoding process: " << mad_stream_errorstr(&stream) << std::endl;
+                    continue;
+                } else {
+                    break;
+                }
+            }
+            
+            mad_synth_frame(&synth, &frame);
+            
+            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(success * samplesPerFrame + j), emscripten::val(value));
+                }
+            }
+        }
+        
+        cachedLength -= available;
+        std::cout << "Processed " << available << " frames, " << success << " successfully, last error " << mad_stream_errorstr(&stream) << std::endl;
+        
+        if (cachedLength == 0) {
+            cached = false;
+            prepareNextBuffer();
+        }
+    }
+    
+    return ret;
+}
+
+bool Decoder::hasMore() const
+{
+    if (pending.size() == 1) {
+        return stream.error != MAD_ERROR_BUFLEN;
+    } else {
+        return true;
+    }
+}
+
+uint32_t Decoder::framesLeft(uint32_t max)
+{
+    if (state == empty || state == onGlueHalf) {
+        cached = true;
+        return 0;
+    }
+    
+    if (cached == false) {
+        mad_stream probe;
+        mad_header ph;
+        initializeProbe(probe);
+        mad_header_init(&ph);
+        
+        while (cachedLength < max) {
+            if (mad_header_decode(&ph, &probe) == 0) {
+                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 (probe.next_frame > probe.this_frame) {
+                    ++cachedLength;
+                }
+            } else {
+                std::cout << "framesLeft::" << mad_stream_errorstr(&probe) << std::endl;
+                if (!MAD_RECOVERABLE(probe.error)) {
+                    break;
+                }
+            }
+        }
+        
+        mad_header_finish(&ph);
+        mad_stream_finish(&probe);
+        std::cout << cachedLength << " frames are available for decoding" << std::endl;
+        cached = true;
+    }
+    
+    return std::min(cachedLength, max);
+}
+
+void Decoder::pullBuffer()
+{
+    mad_header dummy;
+    mad_header_init(&dummy);
+    while(stream.error == 0 || MAD_RECOVERABLE(stream.error)) {
+        mad_header_decode(&dummy, &stream);
+        std::cout << "pullBuffer:: " << mad_stream_errorstr(&stream) << std::endl;
+    }
+    mad_header_finish(&dummy);
+}
+
+void Decoder::changeBuffer()
+{
+    uint32_t left;
+    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:
+            std::cout << "Having another fragment " << pending[0].length << " bytes long" << std::endl;
+            left = (uint64_t)stream.bufend - (uint64_t)stream.next_frame;
+//             std::cout << "MD_LENGTH_BEFORE: " << stream.anc_bitlen << std::endl;
+            mad_stream_buffer(&stream, pending[0].ptr, pending[0].length);
+            
+            
+            //mad_stream_skip(&stream, left);
+            stream.error = MAD_ERROR_NONE;
+            if (lastSync != -1) {
+                if (lastSync > GLUE_LENGTH / 2) {
+                    std::cout << "Error: bytes to read in the buffer are more then glue buffer can fit LASTSYNC (" << lastSync << ")" << std::endl;
+                    throw 1;
+                }
+                uint64_t target = (uint64_t)stream.buffer + GLUE_LENGTH / 2 - lastSync;
+                while ((uint64_t)(stream.this_frame) < target) {
+//                     std::cout << "pulling" << std::endl;
+                    mad_frame_decode(&frame, &stream);
+                }
+                stream.error = MAD_ERROR_NONE;
+                
+//                 stream.this_frame = stream.buffer + GLUE_LENGTH / 2 - lastSync;
+//                 stream.next_frame = stream.buffer + GLUE_LENGTH / 2 - left;
+//                 stream.sync = 1;
+                
+                lastSync = -1;
+                
+//                 mad_bitptr next_frame;
+//                 mad_bit_init(&next_frame, stream.next_frame);
+//                 stream.anc_ptr    = stream.ptr;
+//                 stream.anc_bitlen = mad_bit_length(&stream.ptr, &next_frame);
+//                 mad_bit_finish(&next_frame);
+//                 
+//                 std::cout << ", MD_LENGTH_AFTER: " << stream.anc_bitlen << std::endl;
+            }
+            
+            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.sync = stream.sync;
+    probe.freerate = stream.freerate;
+    probe.this_frame = stream.this_frame;
+    probe.next_frame = stream.next_frame;
+    probe.ptr.byte = stream.ptr.byte;
+    probe.ptr.cache = stream.ptr.cache;
+    probe.ptr.cache = stream.ptr.cache;
+    probe.anc_ptr.byte = stream.anc_ptr.byte;
+    probe.anc_ptr.cache = stream.anc_ptr.cache;
+    probe.anc_ptr.cache = stream.anc_ptr.cache;
+    probe.anc_bitlen = stream.anc_bitlen;
+    //probe.main_data = stream.main_data;
+    //probe.md_len = stream.md_len;
+    probe.options = stream.options;
+    probe.error = stream.error;
+}
+
+void Decoder::switchToGlue()
+{
+    std::cout << "Switching to glue" << std::endl;
+    uint32_t left = (uint64_t)stream.bufend - (uint64_t)stream.next_frame;
+    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;
+    }
+//     std::cout << "MD_LENGTH_BEFORE: " << stream.anc_bitlen << std::endl;
+    mad_stream_buffer(&stream, glue, GLUE_LENGTH);
+    
+
+    if (lastSync != -1) {
+        if (lastSync > GLUE_LENGTH / 2) {
+            std::cout << "Error: bytes to read in the buffer are more then glue buffer can fit LASTSYNC (" << lastSync << ")" << std::endl;
+            throw 1;
+        }
+        uint64_t target = (uint64_t)stream.bufend - GLUE_LENGTH / 2 - lastSync;
+        while ((uint64_t)(stream.this_frame) < target) {
+//             std::cout << "pulling" << std::endl;
+            mad_frame_decode(&frame, &stream);
+        }
+        stream.error = MAD_ERROR_NONE;
+//         stream.this_frame = stream.bufend - GLUE_LENGTH / 2 - lastSync;
+//         stream.next_frame = stream.bufend - GLUE_LENGTH / 2 - left;
+//         stream.sync = 1;
+        
+//         mad_bitptr next_frame;
+//         mad_bit_init(&next_frame, stream.next_frame);
+//         stream.anc_ptr    = stream.ptr;
+//         stream.anc_bitlen = mad_bit_length(&stream.ptr, &next_frame);
+//         mad_bit_finish(&next_frame);
+//         
+//         std::cout << ", MD_LENGTH_AFTER: " << stream.anc_bitlen << std::endl;
+        
+        lastSync = -1;
+    }
+    //mad_stream_skip(&stream, left);
+    stream.error = MAD_ERROR_NONE;
+    
+    //std::cout << "SKIPLEN (" << stream.skiplen << ")" << std::endl;
+    
+    std::cout << "Freeing the drained fragment" << std::endl;
+    free(pending[0].ptr);
+    pending.pop_front();
+}

decoder.h

@@ -0,0 +1,66 @@
+#ifndef DECODER_H
+#define DECODER_H
+
+/**
+ * @todo write docs
+ */
+#include <deque>
+
+#include <emscripten/val.h>
+#include "mad.h"
+
+#define GLUE_LENGTH 10240
+
+class Decoder {
+public:
+    Decoder();
+    ~Decoder();
+    
+    void addFragment(intptr_t bufferPtr, uint32_t length);
+    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;
+        uint32_t offset;
+        uint32_t gueard;
+    };
+    
+    State state;
+    
+    uint32_t sampleRate;
+    uint8_t channels;
+    uint32_t cachedLength;
+    uint16_t samplesPerFrame;
+    uint8_t* glue;
+    int32_t lastSync;
+    bool cached;
+    
+    mad_synth synth;
+    mad_stream stream;
+    mad_frame frame;
+    emscripten::val context;
+    
+    std::deque<RawBuffer> pending;
+    
+private:
+    void pullBuffer();
+    void changeBuffer();
+    void prepareNextBuffer();
+    void initializeProbe(mad_stream& probe);
+    void switchToGlue();
+};
+
+#endif // DECODER_H

index.html

@@ -12,24 +12,24 @@
   <script src="wrapper.js"></script>
     <input type="file" id="file" name="file" />
   <script>
+    var minPortion = 20480;
+    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];
         
         var reader = new FileReader();
         reader.onload = function(e) {
             decoder = new Module.Decoder();
-            var buffer = reader.result;
-            var src = new Uint8Array(buffer);
-            var ptr = Module._malloc(buffer.byteLength);
-            var arr = new Uint8Array(Module.HEAPU8.buffer, ptr, buffer.byteLength);
-            arr.set(src, 0);
+            createFileFragments(reader.result);
             
-            decoder.addFragment(ptr, buffer.byteLength);
-            schedule();
+            scheduleData();
             ctx.resume();
         }
         reader.readAsArrayBuffer(file);
@@ -37,8 +37,9 @@
     }
     
     function schedule() {
+        decoding = false;
         if (decoder.hasMore()) {
-            var audio = decoder.decode(50);
+            var audio = decoder.decode(20);
             if (audio) {
                 var source = ctx.createBufferSource();
                 source.buffer = audio;
@@ -47,14 +48,55 @@
                 time += audio.duration;
                 
                 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);
+            
+            if (fragments.length) {
+                setTimeout(scheduleData, 50);
+            }
+            
+            if (!decoding) {
+                schedule();
+            }
+        }
+    }
+    
+    function createFileFragments(buffer) {
+        var src = new Uint8Array(buffer);
+        var shoved = 0;
+        
+        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));
+        }
+    }
+    
+    
     document.getElementById("file").addEventListener("change", onChange, false);
   </script>
   </body>

wrapper.cpp

@@ -70,142 +70,3 @@ void MadSynth::frame(const mad_frame* frame)
 {
     mad_synth_frame(this, frame);
 }
-
-Decoder::Decoder():
-    sampleRate(0),
-    channels(0),
-    cachedLength(0),
-    samplesPerFrame(0),
-    currentBuffer(0),
-    currentBufferLength(0),
-    synth(),
-    stream(),
-    frame(),
-    context(0)
-{
-    mad_frame_init(&frame);
-    mad_stream_init(&stream);
-    mad_synth_init(&synth);
-    
-    emscripten::val AudioContext = emscripten::val::global("AudioContext");
-    if (!AudioContext.as<bool>()) {
-        printf("No global AudioContext, trying webkitAudioContext\n");
-        AudioContext = emscripten::val::global("webkitAudioContext");
-    }
-
-    printf("Got an AudioContext\n");
-    context = AudioContext.new_();
-}
-
-Decoder::~Decoder()
-{
-    context.call<void>("close");
-    
-    mad_synth_finish(&synth);
-    mad_stream_finish(&stream);
-    mad_frame_finish(&frame);
-    
-    if (currentBuffer != 0) {
-        free(currentBuffer);
-    }
-}
-
-void Decoder::addFragment(intptr_t bufferPtr, unsigned long length)
-{
-    if (currentBuffer != 0) {
-        printf("Adding more then 1 fragment is not supported yet");
-        throw 1;
-    }
-    currentBuffer = (unsigned char(*))bufferPtr;
-    currentBufferLength = length;
-    
-    mad_stream_buffer(&stream, currentBuffer, currentBufferLength);
-    framesLeft();
-}
-
-emscripten::val Decoder::decode(uint32_t count)
-{
-    emscripten::val ret = emscripten::val::undefined();
-    
-    int available = framesLeft(count);
-    if (available > 0) {
-        ret = context.call<val>("createBuffer", channels, available * samplesPerFrame, sampleRate);
-        
-        std::vector<emscripten::val> chans(channels, emscripten::val::undefined());
-        for (int i = 0; i < channels; ++i) {
-            chans[i] = ret.call<val>("getChannelData", i);
-        } 
-        
-        for (int i = 0; i < available; ++i) {
-            mad_frame_decode(&frame, &stream);
-            mad_synth_frame(&synth, &frame);
-            
-            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), val(value));
-                }
-            }
-        }
-        
-        cachedLength -= available;
-        
-        if (cachedLength == 0) {
-            framesLeft();
-        }
-    }
-    
-    return ret;
-}
-
-bool Decoder::hasMore() const
-{
-    if (currentBuffer == 0) {
-        return false;
-    }
-    
-    return stream.error != MAD_ERROR_BUFLEN;
-}
-
-uint32_t Decoder::framesLeft(uint32_t max)
-{
-    if (currentBuffer == 0) {
-        return 0;
-    }
-    
-    if (cachedLength == 0) {
-        mad_stream probe;
-        mad_header ph;
-        mad_stream_init(&probe);
-        mad_header_init(&ph);
-        
-        mad_stream_buffer(&probe, currentBuffer, currentBufferLength);
-        mad_stream_skip(&probe, stream.skiplen);
-        
-        while (cachedLength < max) {
-            if (mad_header_decode(&ph, &probe) == 0) {
-                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;
-                    }
-                }
-                ++cachedLength;
-            } else {
-                if (!MAD_RECOVERABLE(probe.error)) {
-                    std::cout << "framesLeft::" << probe.error << std::endl;
-                    break;
-                }
-            }
-        }
-        
-        mad_header_finish(&ph);
-        mad_stream_finish(&probe);
-    } 
-    
-    return std::min(cachedLength, max);
-}
-

wrapper.h

@@ -5,6 +5,7 @@
 #include <emscripten/val.h>
 
 #include "mad.h"
+#include "decoder.h"
 
 using namespace emscripten;
 
@@ -118,29 +119,7 @@ public:
 
 MadSynth* mad_synth_create();
 
-class Decoder {
-public:
-    Decoder();
-    ~Decoder();
 
-    void addFragment(intptr_t bufferPtr, unsigned long length);
-    val decode(uint32_t count = UINT32_MAX);
-    bool hasMore() const;
-    uint32_t framesLeft(uint32_t max = UINT32_MAX);
-    
-private:
-    uint32_t sampleRate;
-    uint8_t channels;
-    uint32_t cachedLength;
-    uint16_t samplesPerFrame;
-    unsigned char* currentBuffer;
-    unsigned long currentBufferLength;
-    
-    mad_synth synth;
-    mad_stream stream;
-    mad_frame frame;
-    val context;
-};
 
 EMSCRIPTEN_BINDINGS(jsmad) {
     enum_<mad_layer>("mad_layer")