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Hierarchical Coding of Moving Pictures
Špaček, Milan ; Rášo, Ondřej (referee) ; Schimmel, Jiří (advisor)
Bachelor‘s thesis deals with hierarchical coding – scaling – of moving pictures in currently widely used compression algorithms MPEG-2 and MPEG-4. Scaling is the process whereby the encoded data stream is divided into graduated layers, adapted especially to the possibilities of transmission media and capabilities of terminal devices. The content of the base layer is a signal with reduced quality. The content of one or more extension layers is a supplementary picture information, completing the signal to a full quality form. The decoder, depending on its abilities and external circumstances, can decode only the relevant layers from the received bitstream. The thesis focuses in the theoretical part on the detailed description of encoding and decoding video signal according to MPEG standards using three types of scalability. In the concrete, the spatial, qualitative SNR and Fine granular scalability are mentioned. In the practical part of thesis was created an educational application in Matlab environment with its own graphical user interface, which implements the functions performing spatial, qualitative SNR and Fine granular scalability. Based on the user-specified input parameters, it performs scaling the image and then displays the outputs of individual layers after scaling and after the image reconstruction. The input of the programme, in which a hierarchical coding is done, is the image in bitmap format with any size in RGB format.
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Control of Real-Time Digital Audio Signal Processing Algorithms using HTML Browser
Slováček, Martin ; Mačák, Jaromír (referee) ; Schimmel, Jiří (advisor)
VST (Virtual Studio Technology) is one of the most used for real-time audio processing. VST effects are inserted to host applications in the form of plug-ins. This thesis discusses a design of a VST host remote control using a Java applet displayed in a web browser. A graphical user interface of the applet consists of graphical controllers created in this thesis. The number of controlled parameters is passed on to the applet by server using an XML configuration file. Three types of controllers are available: a slider, a knob and a button. If a parameter value change occurs, the applet sends a message with the parameter values to the server. Subsequently, the server reacts to this change by setting the parameters of the loaded VST module. The proposed design was completely realized and practically tested.
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Near-field measurement of a modular subwoofer unit
Borodáč, Samuel ; Schimmel, Jiří (referee) ; Balík, Miroslav (advisor)
The bachleor thesis describes influence of the type of loudspeaker baffle and methods of measuring the subwoofer unit on the frequency response at low frequencies. The work describes the configuration of measurements and the procedure in the analysis software APx500, as well as the export and evaluation of measured values. Moreover, the thesis also includes the results of measurements, its brief analysis and observation of phenomena affecting the measurement of the modular frequency response of the loudspeaker unit in the near field, as well as achieving the overall resulting frequency response of the loudspeaker unit.
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Design and Realization of Modification of Acoustic Field in Laboratory
Ješko, Petr ; Rášo, Ondřej (referee) ; Schimmel, Jiří (advisor)
The thesis deals with the problems of closed spaces. It deals with situations where it is necessary to reduce the reverberation time in certain octave bands. It provides procedures comparing conventional method of solving by calculation of the mean sound absorption coefficient of the area and the subsequent experimental addition of acoustic absorbers which occupy different areas and method that uses an acoustic simulation software for the 3D model. It also deals with a concept of Reflection Phase Grating diffuser.
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Design and Construction of Transmission Line Loudspeaker Cabinet
Dobiášovský, Jiří ; Schimmel, Jiří (referee) ; Balík, Miroslav (advisor)
Thesis is dealing with the topic of design and construction of the transmission line loudspeaker enclosures. Theoretical part is focused on speaker choice, its design elements and their influence on parameters of the speaker. Individual parameters of the speaker, mathematical equations for their determination and choice of suitable speaker for transmission line loudspeaker enclosure is furthermore discussed and defined. Principle of transmission line enclosures is discussed together with its advantages and disadvantages compared to other types of enclosures. The individual design elements and their influence on the resulting characteristics of the enclosure are described. In the practical part, with regard to the facts stated in the theoretical part of the work, a suitable speaker is selected and the subsequent design and construction of a variable transmission line speaker is described. This might serve as a teaching aid in future. Part of the work is also a description of procedures for measuring loudspeakers with multiple speakers or resonators.
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Software for simulation of acoustic pressure distribution
Hampl, Filip ; Schimmel, Jiří (referee) ; Kurc, David (advisor)
This semestral thesis deals with the creation of software to simulate the distribution of sound pressure. Basic principles of sound propagation are explained which are necessary for an understanding of the issue. There is a description of the velocity potential and its application in creating simulations. Another issue is the introduction of wavefield synthesis, which is essentially a technology for simulation of primary sources with secondary sources. Advantages of wavefiled synthesis are discussed as well as disadvantageous aspects. The practical part of this work is creating a user interface in Matlab, which allows user to plot the distribution of sound pressure of one or interaction of more emitters. Another possible outcome is to display the directional characteristics of real resources. At the very end of the work the direction of further work is outlined.
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Acoustic Signal Pickup and Processing Using B Format Technology
Wiesner, Jakub ; Vlach, Jan (referee) ; Schimmel, Jiří (advisor)
The work is aimed to proposal of system for acoustic signal pickuping, software processing and conversion into signals for surround sound systems. The work describes sound sensation by human auditory organ and associated effects of binaural hearing and multichannel stereo and surround sound systems. Next aim of the work is to describe ambisonics, surround sound and formats for surround sound pickuping, transmission, processing a decoding. An ending part introduces problems of surround sound pickuping by using of SoundField technology and output signals decoding process of this technology into signals of other surround sound systems.
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Measurement of Non-Linear Properties of Loudspeakers
Friml, Vilém ; Balík, Miroslav (referee) ; Schimmel, Jiří (advisor)
This thesis deals with calculation of THD dependency on signal frequency and calculation of Rub & buzz distortion using MATLAB software. Thesis includes generation of signals suited for THD measurement, playback and recording using sound card and APx series 500 device. The APx device controlling and data acquisition by MATLAB is also addressed. Loudspeaker electric model is discussed for the use of Rub & buzz measurement.
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Video sequence for supporting audio signal processing classes
Pavlikovský, Vladislav ; Schimmel, Jiří (referee) ; Balík, Miroslav (advisor)
This bachelor theses deals with making of instructional video for supporing audio signal processing classes. The theses is divided into three parts. The firs part is theoretical analysis of spatial effects, processing in time domain and processing in frequency domain. The second part is practical realization of effect panorama, moorers reberator, algorithm PSOLA and algorithm for robotization. The third part of theses is dealing with settings of Windows Media Encoder, which is suitable software for capturing video during a work on signal processing in Matlab and Simulink. The output of the thesis are two instructional videos, that should demostrate signal processing in Simulink.
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