The coding efficiency of HEVC standard was compared with earlier codecs in. The authors have compiled a large-scale database of video sequences whose quality was subjectively evaluated. Human perception of compression, spatial and temporal information was examined in. Coding structures, syntax, various tools, and settings relevant to coding effectivity were described in that paper. There are several research papers that deal with QoS and QoE evaluation, especially the performance assessment of various compression standards or the effect which has the transmission over noisy communication channel on the video quality. Moreover, further examination of the combined impact of PLR and compression on subjective video quality is described. In addition, the analysis of the subjective results is extended by the calculation of the correlation with the objective assessment results. Analogously, Section 5 covers subjective video-quality evaluation. Section 4 deals with the acquisition and analysis of the results of objective video quality assessment. Section 3 illustrates the dataset compilation procedure, and briefly describes the source sequences and the process of video encoding and packet loss simulation. As a result, this paper also suggests the most suitable combination of resolution, bit rate, and codec for use under different conditions. Additionally, the principle of the subjective ACR method enabled further research into the combined effect of PLR and compression parameters on perceived video quality. Objective and subjective evaluation methods, namely peak signal-to-noise ratio (PSNR), Structural Similarity Index (SSIM), and absolute category rating (ACR) were employed for video-quality quantification. The different combinations of the resolution and compression parameters were used. This paper is focused primarily on evaluating the influence of PLR on the quality of H.264/AVC and H.265/HEVC-encoded full HD and ultra HD video sequences. This is proven in the following sections of the paper. It is due to consider that even a small percentage of lost packets can cause a massive decline in perceived video quality. Of the latter, the factor which affects video quality the most is undoubtedly PLR. The major sources of impairments are video compression and transmission over the noisy communication channel. One of the reasons is that this type of application operates on RTP over unreliable UDP. However, the video delivered over an IP network in real-time applications, is often exposed to various types of quality degradation. Nowadays, one of the most popular network services is live video streaming, which is growing on a huge scale. However, although such factors are easily measurable, QoE cannot be quantified so effortlessly. In the field of video transmission, these further depend on factors such as latency, jitter, or packet loss rate (PLR). This individual user impression, also referred to as quality of experience (QoE) is highly dependent on quality of service (QoS) parameters. Much like the rest of the world, Internet service providers, as well as broadcasting companies, want to bring their customers the best possible experiences. Naturally, this applies to expectations in all areas of life, including entertainment and technology. Additionally, the paper includes recommendations of compression parameters for use under various network conditions.Ī high standard of living, education, and more opportunities, along with people’s demands for such better conditions, has been constantly increasing over the last decades. The experiments further led to a finding that the quality of sequences affected by PLR declines with increasing bit rate. Analysis of the results confirmed the presumption that video quality decreases along with the rise of packet loss rate, regardless of compression parameters. Objective assessment was conducted by using peak signal to noise ratio (PSNR) and Structural Similarity Index (SSIM) metrics, whereas the well-known absolute category rating (ACR) was used for subjective evaluation. For the purposes of the research, a dataset containing 11,200 full HD and ultra HD video sequences encoded to H.264 and H.265 formats at five bit rates was compiled with a simulated packet loss rate (PLR) ranging from 0 to 1%. This paper analyzes the adverse impact of packet loss on video quality encoded with various combinations of compression parameters and resolutions. The most significant is the combined effect of video compression and its transmission over the communication channel. Video delivered over IP networks in real-time applications, which utilize RTP protocol over unreliable UDP such as videotelephony or live-streaming, is often prone to degradation caused by multiple sources.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |