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This paper deals with the impact of content on the perceived video quality evaluated using the subjective Absolute Category Rating (ACR) method. The assessment was conducted on eight types of video sequences with diverse content obtained from the SJTU dataset. The sequences were encoded at 5 different constant bitrates in two widely video compression standards H.264/AVC and H.265/HEVC at Full HD and Ultra HD resolutions, which means 160 annotated video sequences were created. The length of Group of Pictures (GOP) was set to half the framerate value, as is typical for video intended for transmission over a noisy communication channel. The evaluation was performed in two laboratories: one situated at the University of Zilina, and the second at the VSB—Technical University in Ostrava. The results acquired in both laboratories reached/showed a high correlation. Notwithstanding the fact that the sequences with low Spatial Information (SI) and Temporal Information (TI) values reached better Mean Opinion Score (MOS) score than the sequences with higher SI and TI values, these two parameters are not sufficient for scene description, and this domain should be the subject of further research. The evaluation results led us to the conclusion that it is unnecessary to use the H.265/HEVC codec for compression of Full HD sequences and the compression efficiency of the H.265 codec by the Ultra HD resolution reaches the compression efficiency of both codecs by the Full HD resolution. This paper also includes the recommendations for minimum bitrate thresholds at which the video sequences at both resolutions retain good and fair subjectively perceived quality.

In the last years the demand trend of multimedia services has rapidly increased. Hand in hand with that growth goes video quality assessment. Recently many studies deal with exploring the video quality using objective or subjective methods but not many examine the relationship between them. Therefore, the goal of this paper is to compare some of the well-known objective and subjective methods and to find out relationship between them. These results could be used for proposing a novel model which could determine the quality using selected objective metric without need to do subjective tests.

This paper analyzes the coding efficiency of recent compression formats H.264, H.265 and AV1 for the visual weather prediction purpose. It compares the bitrate saving of these codecs using objective metrics. The analysis is done on 8 video sequences at Full HD and Ultra HD resolutions. We discovered, that bitstream saving of AV1 is approximately 50% higher than H.264 for both resolutions, 30% higher than H.265 encoded videos at Full HD and 20% higher than those at Ultra HD resolution. From the experimental results, we can also state that objective video quality is content dependent.

With the growth of QoE interest, IPTV providers need a method to control QoE. The paper describes the correlation between the results of objective and subjective methods in video quality assessment. The authors proposed the optimal mapping function for predictions of the subjective quality evaluation based on the objective evaluation to determine the perception of the video quality by the human brain. Our model using artificial intelligence, it is based on a neural network which can simulate and predicts the subjective quality of the scene. It also can predict subjective or objective video quality for video sequences defined by spatial, temporal information, which is the critical and key variable of a given scene, and by the qualitative parameters of the scene. The results from the model are verified by comparing predicted video quality using the proposed classifier with the required value. The two most common statistical parameters related to express performance are Pearson’s correlation coefficient and Root Mean Square Error.

This paper deals with the influence of bit depth on the subjective video quality assessment. To achieve this goal, eight video sequences, each representing a different content prototype, were analysed. Subjective evaluation was performed using the ACR method. The analysed video sequences were encoded to 8 and 10-bit bit depth. Two most used compression standards H.264 and H.265 were evaluated with 1, 3, 5, 10 and 15 Mbps bitrate in Full HD and UHD resolution. Finally, the perceived quality of both compression standards using the subjective tests with emphasis on bit-depth was compared. From the results we can state, that the practical application of 10-bit bit depth is not appropriate for Full HD resolution in the range of bitrate from 1 to 15 Mbps, for Ultra HD resolution, it is appropriate only for videos encoded by H.265/HEVC compression standard.

This paper deals with the impact of constant rate factor value on the objective video quality assessment using PSNR and SSIM metrics. Compression efficiency of H.264 and H.265 codecs defined by different Constant rate factor (CRF) values was tested. The assessment was done for eight types of video sequences depending on content for High Definition (HD), Full HD (FHD) and Ultra HD (UHD) resolution. Finally, performance of both mentioned codecs with emphasis on compression ratio and efficiency of coding was compared.

The most accurate method to obtain QoE is doing subjective tests, that are time-consuming and costly. It is necessary to bridge the gap between how the human brain perceives video quality and distortions introduced in the delivery chain. The main issue of this paper is how to correct interpret and convert the objective score to the subjective point of view. The authors developed mapping function between these two methods using for evaluation of the video quality. We bring a new model for prediction of the subjective quality based on objective, using artificial intelligence.

This paper deals with a video content classification based on spatial and temporal information. The main goal of the paper is to find out whether the non-expert test subjects are able to correctly recognize the spatial and temporal information and how precise is the corresponding parameterization of video content based on these two attributes. Moreover, how well do the objective values provided by the tool deployed in this experiment correlate with the subjective ones. The subjective measurement has shown that the non-expert test subjects are able to correctly recognize the spatial and temporal information only for the extreme scenes in terms of the spatial and temporal information but have experienced some problems when it comes to a more granular classification. When it comes to the objective assessment, the SI and TI values provided by the tool used in this experiment correlate quite well with the subjective data obtained from the basic test for the spatial information.

In the last years, the interest on multimedia services has significantly increased. This leads to requirements for quality assessment, especially in video domain. Compression together with the transmission link imperfection are two main factors that influence the quality. This paper deals with the assessment of the Group of Pictures (GoP) impact on the video quality of VP9 compression standard. The evaluation was done using selected objective and subjective methods for two types of Full HD sequences depending on content. These results are part of a new model that is still being created and will be used for predicting the video quality in networks based on IP.

In recent years, an interest in multimedia services has become a global trend and this trend is still rising. The video quality is a very significant part from the bundle of multimedia services, which leads to a requirement for quality assessment in the video domain. Video quality of a streamed video across IP networks is generally influenced by two factors “transmission link imperfection and efficiency of compression standards. This paper deals with subjective video quality assessment and the impact of the compression standards H.264, H.265 and VP9 on perceived video quality of these compression standards. The evaluation is done for four full HD sequences, the difference of scenes is in the content“ distinction is based on Spatial (SI) and Temporal (TI) Index of test sequences. Finally, experimental results follow up to 30% bitrate reducing of H.265 and VP9 compared with the reference H.264.

This paper deals with the dependence of Constant Rate Factor (CRF) on the bitrate for most commercial used compression standards H.264 and H.265. The measurements were done for eight different video sequences with high resolutions (HD, Full HD, Ultra HD) depending on content. The results indicated biggest differences in the coding efficiency in CRF range from 10 to 20 and from 40 to 51 by both mentioned codecs.

In the last years the interest on multimedia services has rapidly increased which leads to requirements of quality assessment, especially in video domain. Compression together with transmission link imperfection are two main factors that influence the quality. This paper deals with the video quality assessment of the impact of VP9 compression standard using both objective and subjective methods for Full HD resolution. Afterwards the correlation between all objective and subjective methods is calculated as well as the mapping procedure of selected objective method into the subjective MOS scale is done.

Last few years the interest of multimedia services has rapidly increased. This leads to requirements of quality assessment, especially in video domain. Compression together with transmission link imperfection are two main factors that influence the quality. This paper deals with assessment of impact of VP8 and VP9 compression standards on the video quality using objective metrics and defining theirs efficiency. The evaluation is done for four types of sequences with Full HD and Ultra HD resolutions depending on content. The results showed that VP9 codec yields better compression efficiency than VP8. Based on BjOntegaard model VP9 achieves average bitrate saving 12,77% for FHD and 14,44% for UHD resolution ranging from 5% to 21% depending on content and resolution. For more static sequences the improvement is lower and with greater motion the enhancement rises too.

In the last years the interest of multimedia services has markedly increased. This leads to requirements of quality assessment, especially in video domain. Compression together with transmission link imperfection can be considered as two main factors that influence the quality. This paper deals with assessment of impact of HEVC/H.265 and VP9 compression standards on the video quality for high resolutions using objective metrics and defining theirs efficiency. The evaluation is done for four types of sequences with Full HD and Ultra HD resolutions depending on content. The results showed that there is no big difference between the tested codecs - both reach similar efficiency. The average BD-rate saving of VP9 codec relative to H.265 is only 2,24%.

Interest in new multimedia services has rapidly increased over last years. This concern goes hand in hand with demand for higher bandwidth which leads to need to develop new compression standards as VP9 or H.265/HEVC. This results in requirements for video quality assessment as one main part of the multimedia stream. Compression together with transmission link imperfection are two major factors that influence the quality. This paper deals with assessment of impact of VP9 compression standard on the video quality using different subjective metrics. The evaluation is done for two types of sequences with Full HD resolution depending on content. The main outcome obtained from the results is the determination of the threshold in the means of point where the quality do not rise so swift. This threshold was set between 5 and 7 Mbps. After this threshold the observers did not evaluate the quality of both sequence with quite higher marks which means there is no need to compress the sequences to higher bitrates than to 7 Mbps. These results are part of a new model that is still being created and will be used for predicting the video quality in networks based on IP.