From 7cf0551b85deed68d0eefd51e7b233e5c488f63b Mon Sep 17 00:00:00 2001
From: Tim Redfern <tim@herge.(none)>
Date: Tue, 26 Mar 2013 18:33:54 +0000
Subject: nearly working thumbnailer

---
 rotord/rotor.h | 77 ++++++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 53 insertions(+), 24 deletions(-)

(limited to 'rotord/rotor.h')

diff --git a/rotord/rotor.h b/rotord/rotor.h
index e16520b..de8e686 100755
--- a/rotord/rotor.h
+++ b/rotord/rotor.h
@@ -335,7 +335,7 @@ namespace Rotor {
 	};
 	class base_audio_processor {
 		public:
-			virtual bool process_frame(uint8_t *data,int samples)=0;
+			virtual int process_frame(uint8_t *data,int samples)=0;
 			void init(int _channels,int _bits,int _samples) {
 				channels=_channels;
 				bits=_bits;
@@ -350,7 +350,7 @@ namespace Rotor {
 		public:
 			audio_thumbnailer(){
 				height=64;
-				width=512;
+				width=128;  //fit 
 				data=new uint8_t[height*width];
 				memset(data,0,height*width);
 			}
@@ -360,39 +360,66 @@ namespace Rotor {
 			void init(int _channels,int _bits,int _samples) {
 				base_audio_processor::init(_channels,_bits,_samples);
 				samples_per_column=samples/width;
-				stored_data=new uint8_t[samples_per_column*channels*(bits>>3)];
-				sample=0;
+				column=0; //point thumbnail bitmap
+				out_sample=0; //sample in whole track
+				offset=(int)(pow(2.0,bits)/2.0);
+				scale=1.0/offset;
 			}
-			bool process_frame(uint8_t *data,int samples_in_frame){
+			int process_frame(uint8_t *data,int samples_in_frame){
 				//begin by processing remaining samples
 				//samples per column could be larger than a frame! (probably is)
 				//but all we are doing is averaging
 				int bytes=(bits>>3);
 				int stride=channels*bytes;
-				int next_sample=0;
-				uint64_t accum;
-				while (next_sample<samples_in_frame) {
-					while (sample<samples_in_column&&next_sample<samples_in_frame) {
-						//do the accumulation
+				int in_sample=0;
+				while (in_sample<samples_in_frame&&column<width) {
+					int sample=0;
+					int samples=0;
+					double accum=0;
+					while (sample<samples_per_column&&in_sample<samples_in_frame) {
+						//accumulate squares for this column
 						for (int i=0;i<channels;i++) {
 							int this_val=0;
 							for (int j=0;j<bytes;j++) {
 								this_val+=data[(sample*stride)+(i*bytes)+j]<<j;
 							}
-							accum+=this_val*this_val;
-								next_sample++;
-								sample++;
-							}
+							//convert from integer data format - i.e s16p - to audio signal in -1..1 range
+							//don't know how many bytes we are dealing with necessarily?
+							double val=(this_val-offset)*scale;
+							accum+=val*val;
+							samples++;
 						}
-					} do;
-					
-				} do;
-				return true;
+						in_sample++;
+						sample++;
+						out_sample++;
+					}
+					//get root-mean
+					double mean=pow(accum/samples,0.5);
+					int colheight=height*mean*0.5;
+					int hh=height>>1;
+					for (int i=0;i<height;i++) {
+						data[i*width+column]=abs(i-hh)<colheight?0xff:0x00;
+					}
+					column++;
+				}
+				return out_sample;
+			}
+			string print(){
+				string output;
+				for (int j=0;j<height;j++) {
+					for (int i=0;i<width;i++) {
+						output+=data[j*width+i]<0x7f?"0":"1";
+					}
+					output +="\n";
+				}
+				return output;
 			}
 			uint8_t *data;
-			uint8_t *stored_data;
 			int height,width,samples_per_column;
-			int sample;
+			int column,out_sample;
+			//for drawing graph
+			int offset;
+			double scale;
 	};
 	class Render_context: public Poco::Task {				//Poco task object
 													//manages a 'patchbay'
@@ -400,7 +427,8 @@ namespace Rotor {
 													//and low level interface onto the graph
 		public:
 			Render_context(const std::string& name): Task(name)  {
-			    state=IDLE;
+				audio_thumb=new audio_thumbnailer();
+				state=IDLE;
 			};
 			void runTask();
 			void add_queue(int item);
@@ -417,11 +445,12 @@ namespace Rotor {
 
 		private:
 			int state;
-			float progress;								//for a locking process: audio analysis or rendering
+			double progress;								//for a locking process: audio analysis or rendering
 													//thread only does one thing at once
 			std::deque<int> work_queue;
 			Poco::Mutex mutex;            					//lock for access from parent thread
 			std::string audio_filename;
+			audio_thumbnailer *audio_thumb;
 			vampHost::QMAnalyser audio_analyser;
 			xmlIO xml;
 			Graph graph;
@@ -431,6 +460,6 @@ namespace Rotor {
 
 /*
 coding style
-Types begin with a capital, use underscore as a seperator
-instances begin with a small letter
+Types begin with capitals 'CamelCase'
+variables/ instances use lower case with underscore as a seperator
 */
-- 
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