On lossless intra coding in HEVC with 3-tap filters

Alvar, Saeed Ranjbar
Kamışlı, Fatih
This paper presents a pixel-by-pixel spatial prediction method for lossless intra coding within High Efficiency Video Coding (HEVC). Previous pixel-by-pixel spatial prediction methods use only two neighboring pixels for prediction, based on the angular projection idea borrowed from block-based intra prediction in lossy coding, or are based on ad hoc methods applied in some intra modes. This paper explores a pixel-by-pixel prediction method which uses three neighboring pixels for prediction according to a two-dimensional correlation model, and develops a unified prediction algorithm applied in all intra modes with optimized prediction weights and neighbors. The prediction weights for each intra mode are determined from a two-stage offline optimization algorithm and a number of aspects are analyzed to determine a good trade-off between complexity and coding gain. The method is implemented in the HEVC reference software and experimental results show that it can achieve an average 1134% bitrate reduction over the default lossless intra coding in HEVC, which is among the best reported results. The method decreases average decoding time by 12.7% while increasing average encoding time by 9.7%.


Improvement of Transform-Skip Mode in Lossy Intra Coding with 3-Tap Filters
Alvar, Saeed Ranjbar; Kamışlı, Fatih (2016-08-05)
Using transforms in video coding is an effective method in reducing the spatial redundancy. However, for some cases applying transforms does not reduce the spatial redundancy. For these cases, transforms are skipped and the prediction error is directly quantized and then entropy coded. To further reduce the spatial redundancy in the transform skipped blocks, a pixel-by-pixel lossy intra prediction method based on a two dimensional correlation model is proposed in this paper. In the proposed method, three re...
Lossless Intra Coding in HEVC with Adaptive 3-Tap Filters
Alvar, Saeed Ranjbar; Kamışlı, Fatih (2016-08-05)
In pixel-by-pixel spatial prediction methods for lossless intra coding, the prediction is obtained by a weighted sum of neighboring pixels. The proposed prediction approach in this paper uses a weighted sum of three neighbor pixels according to a two-dimensional correlation model. The weights are obtained after a three step optimization procedure. The first two stages are offline procedures where the computed prediction weights are obtained offline from training sequences. The third stage is an online optim...
End-to-end learned image compression with conditional latent space modelling for entropy coding
Yeşilyurt, Aziz Berkay; Kamışlı, Fatih; Department of Electrical and Electronics Engineering (2019)
This thesis presents a lossy image compression system based on an end-to-end trainable neural network. Traditional compression algorithms use linear transformation, quantization and entropy coding steps that are designed based on simple models of the data and are aimed to be low complexity. In neural network based image compression methods, the processing steps, such as transformation and entropy coding, are performed using neural networks. The use of neural networks enables transforms or probability models...
Bici, M. Oguz; Stefanoski, Nikolce; Akar, Gözde (2009-05-06)
In this paper, we propose a Multiple Description Coding (MDC) method for reliable transmission of compressed time consistent 3D dynamic meshes. It trades off reconstruction quality for error resilience to provide the best expected reconstruction of 3D mesh sequence at the decoder side. The method is based on partitioning the mesh vertices into two sets and encoding each set independently by a 3D dynamic mesh coder. The encoded independent bitstreams or so-called descriptions are transmitted independently. T...
Bici, M. Oguz; Akar, Gözde (2008-10-15)
In this paper, we propose a distributed 3D dynamic mesh coding system. The system is based on Slepian and Wolf's and Wyner and Ziv's information-theoretic results. Our system extends the ideas in distributed video coding to 3D dynamic meshes with constant connectivity. The connectivity of the sequence and key frames are encoded and decoded by a conventional static mesh coder. The Wyner-Ziv frames are encoded independent of key frames but decoded jointly with decoded key frames. The joint decoding is perform...
Citation Formats
S. R. Alvar and F. Kamışlı, “On lossless intra coding in HEVC with 3-tap filters,” SIGNAL PROCESSING-IMAGE COMMUNICATION, pp. 252–262, 2016, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/36582.