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Platform for subjective evaluation of video-sequences
Srnec, Tomáš ; Kiska, Tomáš (referee) ; Číka, Petr (advisor)
This bachelor thesis is focused on subjective video quality assessment. Used modern codecs such as H.264, H.265, VP8 and VP9 are described in first chapter. In the next part of the thesis, four methods of the subjective video assessment are being called, according to Recommendation ITU-T P.910. The practical part includes encoding of three videos, into four resolutions, for four codecs. Output of the thesis is JavaFX application, capable of playing used videos for participants of test, who are making judgment. Their results are real-time sent to MySQL server and directly in application evaluated into bar charts. According to our results, the best codec is VP9, before codec H.265, H.264 and VP8.
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Android application for subjective evaluation of video-sequences
Štarha, Dominik ; Přinosil, Jiří (referee) ; Číka, Petr (advisor)
This semestral thesis is focused on a group of four actually used video codecs, namely H.264, HEVC, VP8, VP9. The main objective is to decide on the basis of an evaluation by volunteers which one is the best suitable for video compression. The first part of thesis contains theoretical aspect od the issue. This includes a discussion about the the tested codecs, Android operating system description, performance of the Android Studio software and last but not least, introduction to the assessment methods, used to evaluate video quality, to guarantee the objectivity of the results. The secont part of thesis deals with the implementation of the testing procedure and following evaluation of the data obtained by the assessment.
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Video mixer/translator for web-based videoconference system
Hutar, Jan ; Balík, Miroslav (referee) ; Číka, Petr (advisor)
Bachelor s thesis specialises in a basic description, comparing and processing of video standards H.264 and VP8 in real time. Particularly it concerns a support of videoconfe- rence systems working with those mutually incompatible standards. The work enquires and tests two most considerable software devices convenient with basic requirements for working with video in real time and available with LGLP licence respectively FFmpeg and GStreamer. The thesis suggests practice video mix implementation of data input and the way of code translation into required outgoing stream. FFmpeg tool has been used for realization and message of mixer/translator and simple interface has been established available from web browser with assistance of HTML, PHP and Javascript.
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Comparison of Video Codecs
Urbánek, Pavel ; Svoboda, Pavel (referee) ; Bařina, David (advisor)
This thesis is aimed at analysis of video codecs and their comparison. First part of this document provides reader with the basic information on encoding and decoding process including high level description of often used algorithms. It describes codecs and the process of standardization. Second part is focused on test specifications and codecs comparsion itself including conclusion. PSNR, SSim and BD-PSNR are key methods used for comparing codecs.
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Transmitting Streamed Video on Windows Phone
Jež, Adam ; Zachariáš, Michal (referee) ; Herout, Adam (advisor)
The main goal of this bachelor thesis is the design and implementation of an application for mobile system Windows Phone which will be able to broadcast a multimedia stream from the mobile device camera via a packet network. The RTSP protocol is used to establish the connection and to negotiate the transmission conditions. The multimedia data themselves are sent via the RTP protocol. The aforementioned protocols and follow protocols such as RTCP and SDP are described in the thesis. Also the development of the multimedia application for Windows Phone is briefly described. The last part of the thesis deals with the impact of the transportation protocol on the quality of the video. The main result of the thesis is an application almost ready to be published.
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Image compression in interactive applications in digital video broadcasting
Bodeček, Kamil ; Vrba, Kamil (advisor)
Compressed images are used very frequently in interactive applications in digital video broadcasting. New methods increasing efficiency of the image transmission in digital video broadcasting networks are proposed. Adaptive spatial filtering methods have been proposed for enhancement of the visual perception of the compressed images. New optimalization method is based on application of the filtering algorithms on more compressed images (data size are reduced). Visual quality enhancement is processed in interactive application. Further, new compression methods JPEG2000 and H.264 for image compression have been analysed. Novel compound image compression method for standard and high spatial television resolution is proposed in the thesis.
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Comparison of compression algorithms for high definition video
Dvořák, Martin ; Polák, Ladislav (referee) ; Slanina, Martin (advisor)
Bachelor's thesis deals with comparison and analysis of various instruments of the present-day compression algorithms used to compress high-definition video. Video sequences require a large amount of memory for their storage and take up bandwidth for their transmission, so it is necessary to compress video signals with regard to the quality of video after decompressing. The work focuses mainly on the differences between the algorithms and overall performance. Part of this work is a compressed video database, comparing the performance of different algorithms and the subjective quality of compressed video.
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Tools for measuring video quality without reference
Zach, Ondřej ; Dostál, Petr (referee) ; Slanina, Martin (advisor)
This diploma thesis deals with objective video quality assessments without reference. Some of the basics of video quality evaluation are described. Also some basic conditions for objective video quality metrics are introduced. The main focus of the thesis are no-reference approaches. Thesis tries to describe basic methods for seeking distortion in video. The difference between spatial-domain oriented and spectral-domain oriented metrics is analyzed. We also describe design of tool for measuring objective video quality in Matlab environment. We then designed and implemented a bit-stream oriented metric for estimation of the PSNR of H.264 coded sequences. Finally, we created a database of video sequences and we held objective tests. Results were compared with results from subjective measurements.
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Implementing a Video Quality Metric in the H.264/AVC Decoder
Grúbel, Michal ; Číka, Petr (referee) ; Slanina, Martin (advisor)
In this diploma thesis an algorithm for the evaluation of picture quality of H.264-coded video sequences is introduced and applied. As a measure of picture quality objective metric the peak signal to noise ratio (PSNR) is used. While the computation of the PSNR usually requires a reference signal and compares it to the distorted video sequence, this algorithm is able to evaluate PSNR following the coded transform coefficients. Thus, no reference signal is needed.
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