From 224b7bfc0bfd628da49d5d1fc8b7aec4998aadea Mon Sep 17 00:00:00 2001
From: Joshua Moerman <lakseru@gmail.com>
Date: Tue, 19 Aug 2014 08:21:29 +0200
Subject: [PATCH] Adds possibility to do asymmetric fingerprint comparison Adds
 another metric (doesn't work yet) Adds more constness

---
 lib/CMakeLists.txt                            |  4 +-
 lib/av.hpp                                    |  2 +-
 lib/fingerprint_traits.hpp                    | 16 ++++
 lib/fingerprints.hpp                          |  4 +
 lib/fingerprints/downscale.cpp                | 35 +++++++++
 lib/fingerprints/downscale.hpp                | 27 +++++++
 .../wavelet.cpp}                              | 77 ++++++++++---------
 .../wavelet.hpp}                              | 22 ++----
 lib/image_database.cpp                        |  2 -
 lib/image_database.hpp                        | 16 ++--
 lib/image_io.cpp                              | 63 ++++++++++++++-
 lib/image_io.hpp                              |  6 +-
 src/compress.cpp                              |  3 +-
 src/fingerprint_test.cpp                      | 10 ++-
 src/main.cpp                                  | 51 ++++++------
 src/needle.cpp                                | 14 ++--
 src/writer.cpp                                | 58 +-------------
 17 files changed, 247 insertions(+), 163 deletions(-)
 create mode 100644 lib/fingerprint_traits.hpp
 create mode 100644 lib/fingerprints.hpp
 create mode 100644 lib/fingerprints/downscale.cpp
 create mode 100644 lib/fingerprints/downscale.hpp
 rename lib/{fingerprint.cpp => fingerprints/wavelet.cpp} (50%)
 rename lib/{fingerprint.hpp => fingerprints/wavelet.hpp} (68%)
 delete mode 100644 lib/image_database.cpp

diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 2ad3b1d..dda9976 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -1,6 +1,6 @@
 
-file(GLOB sources "*.cpp")
-file(GLOB headers "*.hpp")
+file(GLOB_RECURSE sources "*.cpp")
+file(GLOB_RECURSE headers "*.hpp")
 
 set(libs avformat avcodec avutil swscale)
 
diff --git a/lib/av.hpp b/lib/av.hpp
index 55ef0cc..c943e5c 100644
--- a/lib/av.hpp
+++ b/lib/av.hpp
@@ -44,7 +44,7 @@ namespace av {
 	// AVFrame related
 	using frame = std::unique_ptr<AVFrame, deleter<AVFrame>>;
 	frame frame_alloc();
-	frame frame_clone(frame const & f);
+	frame frame_clone(frame const & f); // creates a clone with the *same* buffer
 	AVPixelFormat get_format(frame const & f);
 
 	// Allocator
diff --git a/lib/fingerprint_traits.hpp b/lib/fingerprint_traits.hpp
new file mode 100644
index 0000000..10e3076
--- /dev/null
+++ b/lib/fingerprint_traits.hpp
@@ -0,0 +1,16 @@
+#pragma once
+
+#include"av.hpp"
+#include <utility>
+
+// A fingerprint is used to speed up comparison. However, this is done assymetrically. Only the
+// compressed version is used in the database, but for comparison the full image can be used.
+template <typename Fingerprint>
+struct fingerprint_traits {
+	using fingerprint = Fingerprint;
+	using pre_fingerprint = decltype(fingerprint::pre_calculate(std::declval<av::frame>()));
+
+	static pre_fingerprint pre_calculate(av::frame const & frame) { return fingerprint::pre_calculate(frame); }
+	static fingerprint calculate(av::frame const & frame) { return fingerprint::calculate(frame); }
+	static auto distance(fingerprint const & x, pre_fingerprint const & y) { return x.distance_to(y); }
+};
diff --git a/lib/fingerprints.hpp b/lib/fingerprints.hpp
new file mode 100644
index 0000000..5c749dd
--- /dev/null
+++ b/lib/fingerprints.hpp
@@ -0,0 +1,4 @@
+#pragma once
+
+#include "fingerprints/wavelet.hpp"
+#include "fingerprints/downscale.hpp"
diff --git a/lib/fingerprints/downscale.cpp b/lib/fingerprints/downscale.cpp
new file mode 100644
index 0000000..360ac49
--- /dev/null
+++ b/lib/fingerprints/downscale.cpp
@@ -0,0 +1,35 @@
+#include "downscale.hpp"
+
+#include <image_io.hpp>
+#include <algorithm>
+
+downscale downscale::pre_calculate(const av::frame& frame){
+	// ffmpeg doesnt let us downscale all the way to 5 at once :(
+	auto const image = to_raw_rgb_image(frame, 5, 5);
+
+	downscale ret;
+	ret.data.assign(image.data.size(), 0);
+
+	std::copy(image.data.begin(), image.data.end(), ret.data.begin());
+
+	return ret;
+}
+
+downscale downscale::calculate(const av::frame& frame){
+	return pre_calculate(frame);
+}
+
+double square(double x){
+	return x*x;
+}
+
+double downscale::distance_to(const downscale& fingerprint) const {
+	assert(data.size() == fingerprint.data.size());
+
+	double distance = 0;
+	for(size_t i = 0; i < data.size(); ++i){
+		distance += square(data[i] - fingerprint.data[i]);
+	}
+
+	return distance;
+}
diff --git a/lib/fingerprints/downscale.hpp b/lib/fingerprints/downscale.hpp
new file mode 100644
index 0000000..45d65be
--- /dev/null
+++ b/lib/fingerprints/downscale.hpp
@@ -0,0 +1,27 @@
+#pragma once
+
+#include <av.hpp>
+#include <fingerprint_traits.hpp>
+
+#include <boost/serialization/access.hpp>
+#include <boost/serialization/vector.hpp>
+
+#include <iosfwd>
+#include <vector>
+
+struct downscale {
+	std::vector<uint8_t> data;
+
+	static downscale pre_calculate(av::frame const & frame);
+	static downscale calculate(av::frame const & frame);
+	double distance_to(downscale const & fingerprint) const;
+
+private:
+	friend class boost::serialization::access;
+	template<class Archive>
+	void serialize(Archive & ar, const unsigned int /*version*/){
+		ar & data;
+	}
+};
+
+std::ostream& operator<<(std::ostream& out, downscale const & x);
diff --git a/lib/fingerprint.cpp b/lib/fingerprints/wavelet.cpp
similarity index 50%
rename from lib/fingerprint.cpp
rename to lib/fingerprints/wavelet.cpp
index 0c33728..73e0493 100644
--- a/lib/fingerprint.cpp
+++ b/lib/fingerprints/wavelet.cpp
@@ -1,14 +1,37 @@
-#include "fingerprint.hpp"
 #include "wavelet.hpp"
-#include "utilities.hpp"
+#include <wavelet.hpp>
+#include <utilities.hpp>
+#include <image_io.hpp>
 
 #include <ostream>
 #include <cmath>
 
-rgb_wavelet_coefficients rgb_wavelet_coefficients::calculate(const raw_rgb_image& image){
+static const int size = 512;
+
+rgb_wavelet_coefficients::pre_fingerprint rgb_wavelet_coefficients::pre_calculate(av::frame const & frame) {
+	auto const image = to_raw_rgb_image(crop_to_square(frame), size, size);
+	rgb_wavelet_coefficients::pre_fingerprint ret;
+
+	// for every color
+	for(unsigned int color = 0; color < 3; ++color){
+		auto & vector = ret[color];
+		vector.assign(make_u(image.width() * image.height()), 0);
+
+		for(unsigned int n = 0; n < make_u(image.width() * image.height()); ++n){
+			vector[n] = 2.0 * image.data[3*n + color] / double(255) - 1.0;
+		}
+
+		wvlt::wavelet_2D(vector.data(), make_u(image.width()), make_u(image.height()));
+	}
+
+	return ret;
+}
+
+rgb_wavelet_coefficients rgb_wavelet_coefficients::calculate(av::frame const & frame){
+	auto const image = to_raw_rgb_image(crop_to_square(frame), size, size);
 	rgb_wavelet_coefficients ret;
 
-	std::vector<double> vector(make_u(image.width() * image.height()));
+	std::vector<double> vector(make_u(image.width() * image.height()), 0);
 
 	// for every color
 	for(unsigned int color = 0; color < 3; ++color){
@@ -24,12 +47,12 @@ rgb_wavelet_coefficients rgb_wavelet_coefficients::calculate(const raw_rgb_image
 		auto copy = vector;
 		for(auto & x : copy) x = std::abs(x);
 
-		auto n_coefficients = coefficient_array.size();
+		auto const n_coefficients = coefficient_array.size();
 		std::nth_element(copy.begin(), copy.begin() + n_coefficients, copy.end(), std::greater<double>());
-		double threshold = copy[n_coefficients-1];
+		auto const threshold = copy[n_coefficients-1];
 
 		for(unsigned int n = 0; n < vector.size(); ++n){
-			auto x = vector[n];
+			auto const x = vector[n];
 			if(std::abs(x) >= threshold) {
 				coefficient_array[array_index++] = std::make_pair(n, x);
 			}
@@ -46,38 +69,16 @@ static double square(double x){
 	return x*x;
 }
 
-double rgb_wavelet_coefficients::distance_to(const rgb_wavelet_coefficients& y) const {
+double rgb_wavelet_coefficients::distance_to(pre_fingerprint const & fingerprint) const {
 	double distance = 0;
 
 	for(unsigned int color = 0; color < 3; ++color){
-		unsigned int i = 0, j = 0;
-		auto& x_array = color == 0 ? reds : (color == 1 ? greens : blues);
-		auto& y_array = color == 0 ? y.reds : (color == 1 ? y.greens : y.blues);
-
-		// "merge"
-		while(i < x_array.size() && j < y_array.size()){
-			auto x_pair = x_array[i];
-			auto y_pair = y_array[j];
-
-			if(x_pair.first == y_pair.first) {
-				distance += square(y_pair.second - x_pair.second);
-				++i;
-				++j;
-			} else if(x_pair.first < y_pair.first) {
-				distance += square(x_pair.second);
-				++i;
-			} else {
-				distance += square(y_pair.second);
-				++j;
-			}
-		}
+		auto const & coefficients = color == 0 ? reds : (color == 1 ? greens : blues);
 
-		// remaining part, either x or y
-		for(; i < x_array.size(); ++i){
-			distance += square(x_array[i].second);
-		}
-		for(; j < y_array.size(); ++j){
-			distance += square(y_array[j].second);
+		for(auto&& p : coefficients){
+			auto const x = p.second;
+			auto const y = fingerprint[color][p.first];
+			distance += square(x - y) - square(y);
 		}
 	}
 
@@ -95,10 +96,12 @@ std::ostream& operator<<(std::ostream& out, rgb_wavelet_coefficients const & x){
 	out << "rgb_wavelet_coefficients" << std::endl;
 
 	for(int color = 0; color < 3; ++color){
-		auto& coefficient_array = color == 0 ? x.reds : (color == 1 ? x.greens : x.blues);
+		auto const & coefficient_array = color == 0 ? x.reds : (color == 1 ? x.greens : x.blues);
 
 		out << '[' << coefficient_array[0];
-		for(unsigned int i = 1; i < coefficient_array.size(); ++i) out << ", " << coefficient_array[i];
+		for(unsigned int i = 1; i < coefficient_array.size(); ++i) {
+			out << ", " << coefficient_array[i];
+		}
 		out << ']' << std::endl;
 	}
 	return out;
diff --git a/lib/fingerprint.hpp b/lib/fingerprints/wavelet.hpp
similarity index 68%
rename from lib/fingerprint.hpp
rename to lib/fingerprints/wavelet.hpp
index 0c6c16e..6c4f82f 100644
--- a/lib/fingerprint.hpp
+++ b/lib/fingerprints/wavelet.hpp
@@ -1,6 +1,7 @@
 #pragma once
 
-#include "image_io.hpp"
+#include <av.hpp>
+#include <fingerprint_traits.hpp>
 
 #include <boost/serialization/access.hpp>
 #include <boost/serialization/array.hpp>
@@ -9,6 +10,7 @@
 #include <utility>
 #include <array>
 #include <iosfwd>
+#include <vector>
 
 namespace boost {
 	namespace serialization {
@@ -19,28 +21,18 @@ namespace boost {
 	} // namespace serialization
 } // namespace boost
 
-// Default implementation
-template <typename Fingerprint>
-struct fingerprint_traits {
-	static Fingerprint calculate(raw_rgb_image const & image) {
-		return Fingerprint::calculate(image);
-	}
-
-	static auto distance(Fingerprint const & x, Fingerprint const & y) {
-		return x.distance_to(y);
-	}
-};
-
 struct rgb_wavelet_coefficients {
 	// a double for (x, y) location represented in a single int
 	using coefficient = std::pair<int, double>;
+	using pre_fingerprint = std::array<std::vector<double>, 3>;
 
 	std::array<coefficient, 20> reds;
 	std::array<coefficient, 20> greens;
 	std::array<coefficient, 20> blues;
 
-	static rgb_wavelet_coefficients calculate(raw_rgb_image const & image);
-	double distance_to(rgb_wavelet_coefficients const & y) const;
+	static pre_fingerprint pre_calculate(av::frame const & frame);
+	static rgb_wavelet_coefficients calculate(av::frame const & frame);
+	double distance_to(pre_fingerprint const & fingerprint) const;
 
 private:
 	friend class boost::serialization::access;
diff --git a/lib/image_database.cpp b/lib/image_database.cpp
deleted file mode 100644
index ebefd50..0000000
--- a/lib/image_database.cpp
+++ /dev/null
@@ -1,2 +0,0 @@
-#include "image_database.hpp"
-
diff --git a/lib/image_database.hpp b/lib/image_database.hpp
index 61642fc..75c37a2 100644
--- a/lib/image_database.hpp
+++ b/lib/image_database.hpp
@@ -1,7 +1,7 @@
 #pragma once
 
 #include <image_io.hpp>
-#include <fingerprint.hpp>
+#include <fingerprints.hpp>
 
 #include <boost/serialization/access.hpp>
 #include <boost/serialization/vector.hpp>
@@ -13,9 +13,9 @@ template <typename Fingerprint, typename Traits = fingerprint_traits<Fingerprint
 struct image_database {
 	using index = size_t;
 
-	void add(std::string filename){
-		auto image = open_as_rgb(filename);
-		auto fingerprint = Traits::calculate(image);
+	void add(std::string const & filename){
+		auto && image = open_image(filename);
+		auto && fingerprint = Traits::calculate(image);
 
 		filenames.push_back(filename);
 		fingerprints.push_back(fingerprint);
@@ -33,14 +33,14 @@ struct image_database {
 		return fingerprints.size();
 	}
 
-	index nearest_image(raw_rgb_image const & image) const {
-		auto fingerprint = Traits::calculate(image);
+	index nearest_image(av::frame const & image) const {
+		const auto && pre_fingerprint = Traits::pre_calculate(image);
 
 		index best_index = 0;
-		auto best_distance = Traits::distance(fingerprint, fingerprints[0]);
+		auto && best_distance = Traits::distance(fingerprints[0], pre_fingerprint);
 
 		for(index i = 1; i < fingerprints.size(); ++i){
-			auto distance = Traits::distance(fingerprint, fingerprints[i]);
+			const auto && distance = Traits::distance(fingerprints[i], pre_fingerprint);
 			if(distance < best_distance) {
 				best_distance = distance;
 				best_index = i;
diff --git a/lib/image_io.cpp b/lib/image_io.cpp
index 13c8004..be67b95 100644
--- a/lib/image_io.cpp
+++ b/lib/image_io.cpp
@@ -103,6 +103,10 @@ void crop_to_square(av::frame& frame){
 	if(ret < 0) throw std::runtime_error("boem crop");
 }
 
+av::frame crop_to_square(const av::frame& frame){
+	return crop_to_square(av::frame_clone(frame));
+}
+
 av::frame crop_to_square(av::frame && frame){
 	crop_to_square(frame);
 	return std::move(frame);
@@ -120,13 +124,14 @@ raw_rgb_image to_raw_rgb_image(av::frame const & frame, int new_width, int new_h
 }
 
 
-void apply_to_tiles(const std::string& filename, int h_tiles, int v_tiles, std::function<void (int, int, raw_rgb_image const &)> fun){
+void apply_to_tiles(std::string const & filename, int h_tiles, int v_tiles, std::function<void(int, int, av::frame const &)> fun) {
 	auto org_frame = open_image(filename);
 
 	// create clone to crop
 	av::frame cropped_frame = av::frame_clone(org_frame);
 
 	// create raw buffer for the callback
+	// TODO: do not scale the cropped region
 	raw_rgb_image image(512, 512);
 
 	// create the tiles
@@ -144,7 +149,61 @@ void apply_to_tiles(const std::string& filename, int h_tiles, int v_tiles, std::
 			sws_scale (context, {cropped_frame->data}, {cropped_frame->linesize}, 0, cropped_frame->height, {image.frame->data}, {image.frame->linesize});
 			sws_freeContext(context);
 
-			fun(c, r, image);
+			fun(c, r, image.frame);
 		}
 	}
 }
+
+void save_as_jpg(av::frame const & frame, std::string const & filename){
+	const auto pix_fmt = AV_PIX_FMT_YUVJ444P;
+	const auto codec_id= AV_CODEC_ID_MJPEG;
+
+	// Convert
+	int tile_width = 800;
+	int tile_height = 600;
+
+	int h_tiles = 8;
+	int v_tiles = 6;
+
+	std::vector<uint8_t, av::allocator<uint8_t>> data(make_u(avpicture_get_size(pix_fmt, h_tiles * tile_width, v_tiles * tile_height)), 0);
+	av::frame converted_frame = av::frame_alloc();
+	avpicture_fill(reinterpret_cast<AVPicture*>(converted_frame.get()), data.data(), pix_fmt, h_tiles * tile_width, v_tiles * tile_height);
+	converted_frame->width = h_tiles * tile_width;
+	converted_frame->height = v_tiles * tile_height;
+	converted_frame->format = pix_fmt;
+
+	auto const sws_context = sws_getContext(frame->width, frame->height, av::get_format(frame), tile_width, tile_height, av::get_format(converted_frame), 0, nullptr, nullptr, nullptr);
+	if(!sws_context) throw std::runtime_error("boem sws context");
+
+	av::frame cropped_frame = av::frame_clone(converted_frame);
+	for(int r = 0; r < v_tiles; ++r) {
+		for(int c = 0; c < h_tiles; ++c){
+			av_picture_crop(reinterpret_cast<AVPicture*>(cropped_frame.get()), reinterpret_cast<AVPicture*>(converted_frame.get()), av::get_format(converted_frame), r * tile_height, c * tile_width);
+			sws_scale (sws_context, {frame->data}, {frame->linesize}, 0, frame->height, {cropped_frame->data}, {cropped_frame->linesize});
+		}
+	}
+
+	sws_freeContext(sws_context);
+
+	// Encode
+	auto const codec = avcodec_find_encoder(codec_id);
+	if(!codec) throw av::error("Could not find codec");
+
+	auto codec_ctx = std::unique_ptr<AVCodecContext, av::deleter<AVCodecContext>>(avcodec_alloc_context3(codec), [](auto x){ avcodec_free_context(&x); });
+	if(!codec_ctx) throw av::error("Could not allocate codec context");
+
+	codec_ctx->pix_fmt = pix_fmt;
+	codec_ctx->width = converted_frame->width;
+	codec_ctx->height = converted_frame->height;
+	codec_ctx->time_base = av_make_q(1, 1);
+	auto const opened_codec = av::codec_open(codec_ctx.get(), codec, nullptr);
+
+	auto const buffer_size = avpicture_get_size(pix_fmt, codec_ctx->width, codec_ctx->height);
+	std::vector<uint8_t> buffer(make_u(buffer_size), 0);
+	auto const output_size = avcodec_encode_video(codec_ctx.get(), buffer.data(), buffer_size, converted_frame.get());
+	assert(output_size <= buffer_size);
+
+	auto const file = fopen(filename.c_str(), "wb");
+	fwrite(buffer.data(), 1, make_u(output_size), file);
+	fclose(file);
+}
diff --git a/lib/image_io.hpp b/lib/image_io.hpp
index 7c67bf1..bf47609 100644
--- a/lib/image_io.hpp
+++ b/lib/image_io.hpp
@@ -28,6 +28,7 @@ av::frame open_image(std::string const & filename);
 
 // crops to the bottom right square (cheap operation)
 void crop_to_square(av::frame & frame);
+av::frame crop_to_square(av::frame const & frame);
 av::frame crop_to_square(av::frame && frame);
 
 // converts and resizes
@@ -39,4 +40,7 @@ inline raw_rgb_image open_as_rgb(const std::string &filename){
 }
 
 // apply function to every tile, fun :: Column, Row, Image -> Void
-void apply_to_tiles(std::string const & filename, int h_tiles, int v_tiles, std::function<void(int, int, raw_rgb_image const &)> fun);
+void apply_to_tiles(std::string const & filename, int h_tiles, int v_tiles, std::function<void(int, int, av::frame const &)> fun);
+
+// does what you think it does
+void save_as_jpg(av::frame const & frame, std::string const & filename);
diff --git a/src/compress.cpp b/src/compress.cpp
index 159dffd..55cbbe8 100644
--- a/src/compress.cpp
+++ b/src/compress.cpp
@@ -50,6 +50,7 @@ int main(){
 		}
 	}
 
-	save_as_ppm(image, "output.ppm");
+	// TODO: save as jpg
+	save_as_jpg(image.frame, "output.ppm");
 }
 
diff --git a/src/fingerprint_test.cpp b/src/fingerprint_test.cpp
index 85626d0..d5fe8d9 100644
--- a/src/fingerprint_test.cpp
+++ b/src/fingerprint_test.cpp
@@ -1,4 +1,5 @@
-#include <fingerprint.hpp>
+#include <fingerprints.hpp>
+#include <image_io.hpp>
 
 extern "C" {
 #include <libavformat/avformat.h>
@@ -10,10 +11,11 @@ using namespace std;
 
 int main(){
 	av_register_all();
-	auto image = open_as_rgb("test.jpg");
+	auto const image = open_image("test.jpg");
 
-	rgb_wavelet_coefficients x = rgb_wavelet_coefficients::calculate(image);
+	auto const x = rgb_wavelet_coefficients::calculate(image);
+	auto const y = rgb_wavelet_coefficients::pre_calculate(image);
 
 	cout << x << endl;
-	cout << x.distance_to(x) << endl;
+	cout << x.distance_to(y) << endl;
 }
diff --git a/src/main.cpp b/src/main.cpp
index c161bd8..939d3f3 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,7 +1,7 @@
 #include <image_io.hpp>
 #include <wavelet.hpp>
 #include <image_database.hpp>
-#include <fingerprint.hpp>
+#include <fingerprints.hpp>
 
 #include <boost/filesystem.hpp>
 #include <boost/archive/binary_oarchive.hpp>
@@ -21,6 +21,9 @@ extern "C" {
 #include <map>
 #include <set>
 
+static const int tile_width = 128;
+static const int tile_height = 128;
+
 using namespace std;
 namespace fs = boost::filesystem;
 namespace ar = boost::archive;
@@ -29,15 +32,15 @@ using Database = image_database<rgb_wavelet_coefficients>;
 using Mozaic = map<pair<int, int>, string>;
 
 Database read_database(string const & database_directory){
-	image_database<rgb_wavelet_coefficients> db;
-	auto database_file = database_directory + ".db";
+	Database db;
+	auto const database_file = database_directory + ".db";
 
 	if (!boost::filesystem::exists(database_file)){
-		fs::path directory(database_directory);
+		fs::path const directory(database_directory);
 		fs::directory_iterator eod;
 		for(fs::directory_iterator it(directory); it != eod; ++it){
-			auto && path = it->path();
-			auto ext = path.extension();
+			auto const path = it->path();
+			auto const ext = path.extension();
 			if(ext != ".png" && ext != ".jpg") continue;
 
 			cout << colors::green("adding: ") << path.string() << endl;
@@ -50,7 +53,6 @@ Database read_database(string const & database_directory){
 	} else {
 		ifstream file(database_file);
 		ar::binary_iarchive archive(file);
-		// read class state from archive
 		archive >> db;
 	}
 
@@ -59,10 +61,10 @@ Database read_database(string const & database_directory){
 }
 
 Mozaic create_mozaic(Database const & db, string const & filename, int h_tiles, int v_tiles){
-	map<pair<int, int>, string> mozaic;
+	Mozaic mozaic;
 
-	apply_to_tiles("image.jpg", h_tiles, v_tiles, [&](int c, int r, raw_rgb_image const & image){
-		auto index = db.nearest_image(image);
+	apply_to_tiles("image.jpg", h_tiles, v_tiles, [&](int c, int r, av::frame const & frame){
+		auto const index = db.nearest_image(frame);
 		cout << colors::red("tile ") << c << ", " << r << ": " << db.filename(index) << endl;
 		mozaic[make_pair(c, r)] = db.filename(index);
 	});
@@ -71,11 +73,8 @@ Mozaic create_mozaic(Database const & db, string const & filename, int h_tiles,
 }
 
 void save_mozaic(Mozaic const & mozaic, string filename, int h_tiles, int v_tiles){
-	const auto pix_fmt = AV_PIX_FMT_YUVJ444P;
-	const auto codec_id= AV_CODEC_ID_MJPEG;
-
-	int tile_width = 128;
-	int tile_height = 128;
+	auto const pix_fmt = AV_PIX_FMT_YUVJ444P;
+	auto const codec_id= AV_CODEC_ID_MJPEG;
 
 	// Open all files we need
 	map<string, av::frame> frames;
@@ -85,8 +84,8 @@ void save_mozaic(Mozaic const & mozaic, string filename, int h_tiles, int v_tile
 		frames.emplace(x.second, crop_to_square(open_image(x.second)));
 	}
 
-	auto total_width = h_tiles * tile_width;
-	auto total_height = v_tiles * tile_height;
+	auto const total_width = h_tiles * tile_width;
+	auto const total_height = v_tiles * tile_height;
 
 	// Create output frame
 	std::vector<uint8_t, av::allocator<uint8_t>> data(make_u(avpicture_get_size(pix_fmt, total_width, total_height)), 0);
@@ -128,9 +127,9 @@ void save_mozaic(Mozaic const & mozaic, string filename, int h_tiles, int v_tile
 	codec_ctx->time_base = av_make_q(1, 1);
 	auto opened_codec = av::codec_open(codec_ctx.get(), codec, nullptr);
 
-	const auto buffer_size = avpicture_get_size(pix_fmt, codec_ctx->width, codec_ctx->height);
+	auto const buffer_size = avpicture_get_size(pix_fmt, codec_ctx->width, codec_ctx->height);
 	std::vector<uint8_t> buffer(make_u(buffer_size), 0);
-	auto output_size = avcodec_encode_video(codec_ctx.get(), buffer.data(), buffer_size, frame.get());
+	auto const output_size = avcodec_encode_video(codec_ctx.get(), buffer.data(), buffer_size, frame.get());
 	assert(output_size <= buffer_size);
 	cout << "output size" << output_size << endl;
 
@@ -142,14 +141,14 @@ void save_mozaic(Mozaic const & mozaic, string filename, int h_tiles, int v_tile
 int main(){
 	av_register_all();
 
-	string database_directory = "database";
-	string filename = "image.jpg";
-	string output = "output.jpg";
-	int h_tiles = 4 * 13;
-	int v_tiles = 3 * 13;
+	string const database_directory = "database";
+	string const filename = "image.jpg";
+	string const output = "output.jpg";
+	int const h_tiles = 4 * 7;
+	int const v_tiles = 3 * 7;
 
-	const auto db = read_database(database_directory);
-	const auto mozaic = create_mozaic(db, filename, h_tiles, v_tiles);
+	auto const db = read_database(database_directory);
+	auto const mozaic = create_mozaic(db, filename, h_tiles, v_tiles);
 	save_mozaic(mozaic, output, h_tiles, v_tiles);
 
 	// debugging
diff --git a/src/needle.cpp b/src/needle.cpp
index e229328..0090391 100644
--- a/src/needle.cpp
+++ b/src/needle.cpp
@@ -1,7 +1,7 @@
 #include <image_io.hpp>
 #include <wavelet.hpp>
 #include <image_database.hpp>
-#include <fingerprint.hpp>
+#include <fingerprints.hpp>
 
 #include <boost/filesystem.hpp>
 
@@ -19,16 +19,16 @@ namespace fs = boost::filesystem;
 int main(){
 	av_register_all();
 
-	string database_directory = "database";
-	string filename = "needle.jpg";
+	string const database_directory = "database";
+	string const filename = "needle.jpg";
 
 	image_database<rgb_wavelet_coefficients> db;
 
-	fs::path directory(database_directory);
+	fs::path const directory(database_directory);
 	fs::directory_iterator eod;
 	for(fs::directory_iterator it(directory); it != eod; ++it){
-		auto && path = it->path();
-		auto ext = path.extension();
+		auto const path = it->path();
+		auto const ext = path.extension();
 		if(ext != ".png" && ext != ".jpg") continue;
 
 		cout << colors::green("adding: ") << path.string() << endl;
@@ -40,7 +40,7 @@ int main(){
 		cout << colors::green("database: ") << db.size() << endl;
 		cout << colors::green("press enter to search match for: ") << filename << endl;
 		cin.ignore();
-		auto index = db.nearest_image(open_as_rgb(filename));
+		auto const index = db.nearest_image(open_image(filename));
 		cout << colors::green("match: ") << db.filename(index) << endl;
 	}
 }
diff --git a/src/writer.cpp b/src/writer.cpp
index 79cf292..f58ca1e 100644
--- a/src/writer.cpp
+++ b/src/writer.cpp
@@ -9,67 +9,11 @@ extern "C" {
 
 using namespace std;
 
-
-static void save_as_jpg(av::frame const & frame, std::string const & filename){
-	const auto pix_fmt = AV_PIX_FMT_YUVJ444P;
-	const auto codec_id= AV_CODEC_ID_MJPEG;
-
-	// Convert
-	int tile_width = 800;
-	int tile_height = 600;
-
-	int h_tiles = 8;
-	int v_tiles = 6;
-
-	std::vector<uint8_t, av::allocator<uint8_t>> data(make_u(avpicture_get_size(pix_fmt, h_tiles * tile_width, v_tiles * tile_height)), 0);
-	av::frame converted_frame = av::frame_alloc();
-	avpicture_fill(reinterpret_cast<AVPicture*>(converted_frame.get()), data.data(), pix_fmt, h_tiles * tile_width, v_tiles * tile_height);
-	converted_frame->width = h_tiles * tile_width;
-	converted_frame->height = v_tiles * tile_height;
-	converted_frame->format = pix_fmt;
-
-	auto sws_context = sws_getContext(frame->width, frame->height, av::get_format(frame), tile_width, tile_height, av::get_format(converted_frame), 0, nullptr, nullptr, nullptr);
-	if(!sws_context) throw std::runtime_error("boem sws context");
-
-	av::frame cropped_frame = av::frame_clone(converted_frame);
-	for(int r = 0; r < v_tiles; ++r) {
-		for(int c = 0; c < h_tiles; ++c){
-			av_picture_crop(reinterpret_cast<AVPicture*>(cropped_frame.get()), reinterpret_cast<AVPicture*>(converted_frame.get()), av::get_format(converted_frame), r * tile_height, c * tile_width);
-			sws_scale (sws_context, {frame->data}, {frame->linesize}, 0, frame->height, {cropped_frame->data}, {cropped_frame->linesize});
-		}
-	}
-
-	sws_freeContext(sws_context);
-
-	// Encode
-	auto codec = avcodec_find_encoder(codec_id);
-	if(!codec) throw av::error("Could not find codec");
-
-	auto codec_ctx = std::unique_ptr<AVCodecContext, av::deleter<AVCodecContext>>(avcodec_alloc_context3(codec), [](auto x){ avcodec_free_context(&x); });
-	if(!codec_ctx) throw av::error("Could not allocate codec context");
-
-	codec_ctx->pix_fmt = pix_fmt;
-	codec_ctx->width = converted_frame->width;
-	codec_ctx->height = converted_frame->height;
-	codec_ctx->time_base = av_make_q(1, 1);
-	auto opened_codec = av::codec_open(codec_ctx.get(), codec, nullptr);
-
-	const auto buffer_size = avpicture_get_size(pix_fmt, codec_ctx->width, codec_ctx->height);
-	std::vector<uint8_t> buffer(make_u(buffer_size), 0);
-	auto output_size = avcodec_encode_video(codec_ctx.get(), buffer.data(), buffer_size, converted_frame.get());
-	assert(output_size <= buffer_size);
-	cout << "output size" << output_size << endl;
-
-	auto file = fopen(filename.c_str(), "wb");
-	fwrite(buffer.data(), 1, make_u(output_size), file);
-	fclose(file);
-}
-
 int main(){
 	av_register_all();
 
 	while(true){
-		auto image = open_image("needle.png");
+		auto const image = open_image("needle.png");
 		save_as_jpg(image, "output.jpg");
 	}
 }