Error concealment-aware encoding for robust video transmission

In this paper an error concealment-aware encoding scheme is proposed to improve the quality of decoded video in broadcast environments prone to transmission errors and data loss. The proposed scheme is based on a scalable coding approach where the best error concealment (EC) methods to be used at the decoder are optimally determined at the encoder and signalled to the decoder through SEI messages. Such optimal EC modes are found by simulating transmission losses followed by a lagrangian optimisation of the signalling rate - EC distortion cost. A generalised saliency-weighted distortion is used and the residue between coded frames and their EC substitutes is encoded using a rate-controlled enhancement layer. When data loss occurs the decoder uses the signalling information is used at the decoder, in case of data loss, to improve the reconstruction quality. The simulation results show that the proposed method achieves consistent quality gains in comparison with other reference methods and previous works. Using only the EC mode signalling, i.e., without any residue transmitted in the enhancement layer, an average PSNR gain up to 2.95 dB is achieved, while using the full EC-aware scheme, i.e., including residue encoded in the enhancement layer, the proposed scheme outperforms other comparable methods, with PSNR gain up to 3.79 dB

A two-stage approach for robust HEVC coding and streaming

The increased compression ratios achieved by the High Efficiency Video Coding (HEVC) standard lead to reduced robustness of coded streams, with increased susceptibility to network errors and consequent video quality degradation. This paper proposes a method based on a two-stage approach to improve the error robustness of HEVC streaming, by reducing temporal error propagation in case of frame loss. The prediction mismatch that occurs at the decoder after frame loss is reduced through the following two stages: (i) at the encoding stage, the reference pictures are dynamically selected based on constraining conditions and Lagrangian optimisation, which distributes the use of reference pictures, by reducing the number of prediction units (PUs) that depend on a single reference; (ii) at the streaming stage, a motion vector (MV) prioritisation algorithm, based on spatial dependencies, selects an optimal sub-set of MVs to be transmitted, redundantly, as side information to reduce mismatched MV predictions at the decoder. The simulation results show that the proposed method significantly reduces the effect of temporal error propagation. Compared to the reference HEVC, the proposed reference picture selection method is able to improve the video quality at low packet loss rates (e.g., 1%) using the same bitrate, achieving quality gains up to 2.3 dB for 10% of packet loss ratio. It is shown, for instance, that the redundant MVs are able to boost the performance achieving quality gains of 3 dB when compared to the reference HEVC, at the cost using 4% increase in total bitrate

Reference picture selection using checkerboard pattern for resilient video coding

The improved compression efficiency achieved by the High Efficiency Video Coding (HEVC) standard has the counter-effect of decreasing error resilience in transmission over error-prone channels. To increase the error resilience of HEVC streams, this paper proposes a checkerboard reference picture selection method in order to reduce the prediction mismatch at the decoder in case of frame losses. The proposed approach not only allows to reduce the error propagation at the decoder, but also enhances the quality of reconstructed frames by selectively constraining the choice of reference pictures used for temporal prediction. The underlying approach is to increase the amount of accurate temporal information at the decoder when transmission errors occur, to improve the video quality by using an efficient combination of diverse motion fields. The proposed method compensates for the small loss of coding efficiency at frame loss rates as low as 3%. For a single frame-loss event the proposed method can achieve up to 2 dB of gain in the affected frames and an average quality gain of 0:84 dB for different error prone conditions

A robust video encoding scheme to enhance error concealment of intra frames

In this paper a robust encoding scheme is proposed to improve the visual quality of HEVC decoded video when intra frames are lost along the streaming path. For this purpose, the encoding process includes frame loss simulation and subsequent error concealment, to find the most efficient method that should be used by a decoder to recover lost intra frames. In this novel scheme, each image is divided into partitions, which are associated with the error concealment method that achieves the lowest distortion. Then this information is signalled to the decoder through SEI messages in the coded stream. In order to efficiently use the signalling overhead, rate-distortion optimisation is used to achieve the best trade-off between the number of transmitted symbols and distortion of reconstructed frames. Experimental results show the effectiveness of the proposed method to enhance the quality of reconstructed intra frames under different packet loss ratios (PLR). For PLR=10%, the robust coding scheme is able to improve the average PSNR of all frames affected by errors, up to 1.50 dB and 3.44 dB in Low-Delay and Random-Access configurations respectively, at a maximum overhead cost of 0.24%

Reference picture selection using checkerboard pattern for resilient video coding

The improved compression efficiency achieved by the High Efficiency Video Coding (HEVC) standard has the counter-effect of decreasing error resilience in transmission over error-prone channels. To increase the error resilience of HEVC streams, this paper proposes a checkerboard reference picture selection method in order to reduce the prediction mismatch at the decoder in case of frame losses. The proposed approach not only allows to reduce the error propagation at the decoder, but also enhances the quality of reconstructed frames by selectively constraining the choice of reference pictures used for temporal prediction. The underlying approach is to increase the amount of accurate temporal information at the decoder when transmission errors occur, to improve the video quality by using an efficient combination of diverse motion fields. The proposed method compensates for the small loss of coding efficiency at frame loss rates as low as 3%. For a single frame-loss event the proposed method can achieve up to 2 dB of gain in the affected frames and an average quality gain of 0:84 dB for different error prone conditions

Economic profile of two species of Genus der Euterpe, producers of açaí fruits, from the Pará and Amazonas States - Brazil

This study deals with an analysis of the production of the two assaih species (Euterpe precatoria Martius Euterpe Oleracea) occurring in the states of Amazonas and Pará, respectively. In subject to delineate the economic behavior of two açaí pulp producing species, estimates were made based on temporal observations of the secondary data of produced amounts, prices practiced and respect analyses of growth market. The study made it possible to understand the market dynamics of the açaí economic activity from both species of the genus Euterpe. Analyzing data on the quantities produced and several studies on management, production and commercialization, it was possible to trace the apparent profile of the market structure of açaí fruit, where it was verified the strategic importance of investing in plantations of Euterpe precatoria species, because this species besides having higher anthocyanin contents, has its fruit production in the off-season months of E. oleracea. The harvest in alternate periods, adjust the annual supply and, certainly, will contribute to reduce the variation in prices. Over this perspective, was can perceive the social, political, technological, cultural, market and environmental transformations that need to be implemented and taken into account so that this activity may be able to follow an expansion of its demand and in an environment of perfect competition, find its point of balance, within the formats of the economic sustainability

Antibiotics plus probiotic as an adjunct to the treatment of periodontitis in smokers: a short-term study

Aim: The purpose of this study was to perform a short-term evaluation of the effects of a probiotic, associated with the use of antibiotics as an adjuvant treatment of periodontitis in smokers. Materials and Methods: Thirty-four patients were randomly divided into: PRO group (n = 17), patients received a single session of scaling and root planing (SRP) associated with the systemic administration of Lactobacillus reuteri tablets; ANT+PRO group (n=17), patients received a single session of SRP followed by the systemic administration of Amoxicillin and Metronidazole 3x/day for 7 days and administration of Lactobacillus reuteri seven days after conclusion of antibiotic therapy. Clinical periodontal parameters were evaluated. Results: After treatment, both groups showed a reduction in BOP, PI, and residual pockets compared to baseline, while in the ANT+PRO group there was a significant reduction in PD and CAL gain (p5mm was observed in the ANT+PRO group (p<0.05). Conclusion: Both adjuvant treatments reduced the residual pockets and controlled inflammation after treatment. Only the association of antibiotic with probiotic therapy was able to efficiently reduce mean PD, the number of pockets with PD >5 mm, and promote additional CAL gains in a short-term evaluation period