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Audio Saving Module
Strašil, Ivo ; Kouřil, Jiří (referee) ; Říha, Kamil (advisor)
The aim of this thesis was to design and construct an autonomous, hardware voice recorder/player module. The device is made as a compact, built-in component for a motherboard of a target appliance. During recording, the incoming analog voice signal is converted to a digital stream by an ADC with 16 bits resolution and 24 kHz sample rate. Microcontroller LPC2103 (ARM7TDMI core) processes data, recalculates resolution and sample rate, encodes and converts to WAV format and save into a FAT/FAT32 filesystem on a Secure Digital memory card. At playback, the process is opposite: the microcontroller reads file from the memory card, decodes the stream and sends it to a DAC and then to a reconstruction filter. So there is an analog voice signal at the output again. The firmware allows control by logic inputs or by a serial bus, processing of uncompressed WAV files or WAV files with A-law or IMA ADPCM compression, continual recording including automatic freeing of card space by deleting the oldest records and a usage of a voice emphasis filter or of a signal dynamic compression circuit.
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Audio/video streaming
Čeněk, Radek ; Jeřábek, Jan (referee) ; Číka, Petr (advisor)
This thesis introduces the reader in detail with the problem of audio / video streaming overtheInternet.IntroducestechnologiesMySQL,PHP,JavaScriptandffmpegfurthermore. There is little research which examines presented similar solutions. Creating video library program shows the complexity of the problem and its possible solution. The work also finding how is compression difficult for the server.
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Audio D/A converter with external control using microcontroller
Špaček, Jan ; Stifter,, Jiří (referee) ; Kratochvíl, Tomáš (advisor)
This diploma thesis is devoted to the design of a laboratory measurement tool with DAC converter for audio and low frequency signals. In the introduction part a theoretical background of the ADC and DAC conversions are outlined. In the next chapters the technical solution of the laboratory converter is presented, including DAC with integrated circuit AD1852 and completed with digital audio receiver CS8416. This circuit secures compatibility with external audio devices with digital interfaces, like SPDIF or AES3. The digital receiver and audio DAC are added with serial communication interface for setup of the most audio and input parameters. This setup is operated by external microcontroller ATmega32 and original firmware. The thesis presents block diagram and schematic layout of the laboratory converter, including complete technical documentation for the construction and design.
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Audio Interface for Embedded PC
Staroň, Martin ; Hanák, Pavel (referee) ; Schimmel, Jiří (advisor)
The scope of my master thesis is a designing computer sound interface including measurement of audio performance. This work is concerning both design analog front - ends and digital support circuits. The sigma delta Analog to Digital (ADC) and Digital to Analog (DAC) converters is included in this conception. Those converters has been made into two separate printed circuit boards. All signal paths in this circuitry are utilizing differential mode that are quoted as balanced among audio engineers. Modern circuit components are used in this design, such as fully differential operational amplifiers, electronically controlled gain preamplifiers, low drop linear stabilizers with low noise level, DC component suppression circuits and low jitter active components. Theoretical part of this thesis contains specification of choosed sound defitions, questioning audio program loudness leveling. Further criteria of suitable active and passive components are included. In this thesis the simulations of fundamental circuits block are meant likewise. Practical part involve complete layout of printed circuit boards of and prototyping. Designed prototype device has wide application usage. It is intended to use not only as industrial computers, but also as dedicated sound converters, measurement cards, mixing consoles, switching matrixes, active loudspeakers, embedded systems.
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SIP Protocol Implementation
Dušek, Martin ; Zukal, Martin (referee) ; Číka, Petr (advisor)
This Master’s thesis deals in detail with the SIP protocol – a method of communication between two entities, various types of transmitted messages and their content. Few SIP libraries are introduced and two of them are used for development of an application for audio/video conference-calls. Compilation of OPAL and PTlib libraries for Windows 7 Professional (64bit) is described, and problems resulting from lack of information provided by authors. New improved “how to build” is presented. At the end, paper focuses on several ways of development of mentioned application.
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Mobile player for multimedia content presentation and processing
Króner, Tomáš ; Číka, Petr (referee) ; Müller, Jakub (advisor)
Master’s thesis deals with developing of multimedia application that allow play and receive multimedia files as audio and video. In thesis introduction, there is theory overview about programming language J2ME, its parts and divisions in couple of chapters. The applications developing begin by choosing focus groups and also group of devices that agree with present trends about mobile devices. The next part undertakes selecting development tool NetBeans IDE based on requirements for multimedia develop and also undertakes selecting software development kit Nokia SDK and its short definition. Afterwards, the application and its basic classes and methods are briefly characterized. The chapters of classes and methods are divided according algorithm level, following development description dividing aspect. Program functions are enriched with flow diagrams completing written text, which have marked important points of program. The main chapters describing algorithm parts begin with define audio and video play. The other pages include description of network connection a data transfers. In every part the programmer part, algorithm is analyzed first and than general options and functionality of this area. In file play part, it is selection of file and proceeding to launch playing with function control possibility. In case of network connection, it is access to network and data handling, eventually communication with each other in client - server hierarchy and consequential multimedia content playing. In the end of development part, reader is cognizant of application fault handling that is inherently part of every application working with I/O data. Next chapter is devoted to future development a design resulting to present process. In the thesis it can be found also application description from user’s point of view, user manual a solving incurred problem situations. In the instructions, there are contained screenshots of described parts of program. Reached results and reviews are summarized on the end of the thesis.
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Creation and processing of signal database
Glett, Jiří ; Šebesta, Vladimír (referee) ; Sigmund, Milan (advisor)
The work become acquainted with history and rise databases globally. Construes philosophy structuralization, sorting and purpose using. Work further deal with concrete databases softwares intended directly to processing audio signals. Further treat of programmes that the make possible generation personal database structures. Work deal about SUSAS database and analysing its content. It is created self database of music signals, which includes several musical groups always similar in certain aspect. Speech database contains records from the SUSAS database and records from television programs, reality-shows, sports broadcasts, reports and documents, when speakers are subjected to stress and emotions. The work is a database program that can effectively classify all records and processes. The database can be freely extended. The resulting program was realized into Czech and English version.
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