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Real-Time Generation of Band-Limited Digital Audio Signals
Maule, Petr ; Rajmic, Pavel (referee) ; Schimmel, Jiří (advisor)
Master’s thesis deals with the generation of digital audio signals with band-limited frequency spectrum, i.e. without the aliasing distortion. Various methods of generating band-limited rectangular, triangular, and sawtooth waveforms are described in the theoretical part. The described methods are programmed in the Matlab programming environment and compared in terms of real-time parameter changes, such as duty cycle change of rectangular waveform or continuous change of frequency. The main part of the thesis describes implementation of methods of successive integration of band-limited impulse train and method of differentiated parabolic waveforms in C++ language. The implemented methods were integrated into a plug-in of VST technology that generates an audio signal in real time. The implemented methods are compared in terms of computational complexity and distortion of the generated signal.
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Interactive Searching in Online Archive of Visual and Audiovisual Artworks
Kuře, Dominik ; Myška, Vojtěch (referee) ; Schimmel, Jiří (advisor)
This bachelor thesis focuses on development of a web application, which serves as an archive for videos. Each video has a certain amount of keywords. The application uses an already created database and a preinstalled server on which the videos are uploaded. The database was given to the author by his supervisor. Searching through the archive can be done by inputting an expression into a search bar or through a variation of filters that are based on information about each video. The results and the database as a whole are graphically represented by charts, which change their form based on given data. Videos can be played in a video player and a list of similar videos is generated. The list is based on keywords which the videos have in common. The main technologies used in the application are Node.js, React and MariaDB. A good amount of libraries are used for this application, allowing JavaScript to be the primary programming language in all phases of development. The text of this bachelor thesis can be dividen in two parts - theoretical and practical. The first part describes all the technologies and libraries used in the application. An in depth approach was taken especially on those parts of each library which are actually being used in the practical. Apart from the necessary technologies, the reader will be also introduced to libraries and systems which help a programmer with his work such as automatic formatting of code and it's backup, saving different versions of the code or adding static datatypes into JavaScript through TypeScript. The theoretical part should give the reader a summary of how browser applications work and communicate with each other. In the practical part an entire application will be built from scratch. The application will connect four different servers - front-end, back-end, database server and a server storing the videos - and allow them to communicate accordingly. The bachelor thesis also contains information about using different controllers for manipulating the browser.
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VST Plug-IN for audio signal watermarking
Henzl, David ; Schimmel, Jiří (referee) ; Zezula, Radek (advisor)
This thesis deal with digital signal proccessing methods, possibilities their processing and especially audio signal watermarking like possibility safeguard author's rights of audio content. In this thesis are foreshadoweds basic audio watermarking methods and possibilities of watermark detection. To idea generation about watermarking there is described audio watermarking method known as Echo Hiding. This method embed watermarks to audio content in time-domain while watermark detection is made in kepstral-domain by using Fast Fourier Transform and correlation function. Method is implemented like VST plug - in and along with ASIO drivers that minimize signal latency provides audio signal watermarking in real - time. Aim of the first volume of this thesis is introduction of VST technology, ASIO driver and creating VST plug – in‘s. Alternative volume of thesis deal with implementation watermarking methods in conjunction with VST technology.
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Rabdom number generators
Mikulka, Zdeněk ; Schimmel, Jiří (referee) ; Zeman, Václav (advisor)
This thesis concerns with methods of pseudorandom numbers generation. It focus on software generators. There are pseudorandom number generators divided according to the way of generation and described single types. The next part describes methods of testing for quality of random and pseudorandom number generators. They are divided into theoretical and statistical tests. Some of these tests are used on available generators. The evaluation is based on results of these tests.
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Automation of Noise Measurements Using XL2 Sounl Level Meter
Švihálek, Filip ; Číž, Radim (referee) ; Schimmel, Jiří (advisor)
This bachelor´s thesis focuses on noise measurement, characterizes used quantities and uncertainties due to the measument of these quantities. The goal is to develop application, which will automate measurement with sound level meter XL2. Automation will use text output of the XL2 and modul for Remote Measurement. Application is developed in development environment Visual Basic for Applications.
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Small-Size Microphone Array for Estimation of Direction of Arrival of Sound
Kubišta, Ladislav ; Honzík, Petr (referee) ; Schimmel, Jiří (advisor)
This thesis describe detection of direction receiving sound with small–size microphone array. Work is based on analyzing methods of time delay estimation, energy decay or phase difference signal. Work focus mainly on finding of angle of arrival in small time difference. Results of measuring, as programming sound, so sound recorded in laboratory conditions and real enviroment, are mentioned in conclusion. All calculations were done by platform Matlab
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Digital Audio Signal Feature Extraction and Modification in Dynamic Plane
Kramoliš, Ondřej ; Sysel, Petr (referee) ; Schimmel, Jiří (advisor)
This thesis deals with basic methods of root mean square and peak value measurement of a digital acoustic signal, algotithms to measure audio programme loudness and true-peak audio level according to recommendation ITU-R BS.1770-1 and digital systems for control of signal dynamic range. It shows achieved results of root mean square and peak value measurement and results of implementation of dynamic processor with general piecewise linear non-decreasing static curve and algorithms according to recommendation ITU-R BS.1770-1.
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3D Audio Standards in Home Theatre Environment
Kováč, Daniel ; Schimmel, Jiří (referee) ; Balík, Miroslav (advisor)
This work deals with object-based sound. There is a description of the difference between channel-based and object-based sound and the development of this sound to today's form. Subsequently, formats that work with objects are described, and they are compared with each other. MPEGH-3D Audio format is specified here, which is a standard today, and also the method of positioning the virtual audio source by vector-base amplitude panning. It also describes how an encoder and decoder supporting speaker configurations 5.1.2, 5.1.4 and 7.1.4 has been developed according to the MPEG-H 3D Audio specification. Lastly, the work deals with the problem of panning the object sound to the standard configuration and there is also a mention of the listening test.
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