Jin Heo

Improved CAVLC for H.264/AVC Lossless Intra-Coding

Context-based adaptive variable length coding (CAVLC) for the H.264/advanced video coding (AVC) standard was originally designed for lossy video coding, and as such does not yield adequate performance for lossless video coding. In this paper, we propose an improved CAVLC for lossless intra-coding by considering the statistical differences in residual data between lossy and lossless coding. From experimental results, we confirm that the proposed method provides approximately 9% bit saving in terms of a compression ratio compared with the current H.264/AVC fidelity range extensions high profile.

Efficient entropy coding scheme for H.264/AVC lossless video coding

Context-based adaptive variable length coding (CAVLC) and context-based adaptive binary arithmetic coding (CABAC) are entropy coding methods employed in the H.264/AVC standard. Since these entropy coders are originally designed for encoding residual data, which are zigzag scanned and quantized transform coefficients, they cannot provide adequate coding performance for lossless video coding where residual data are not quantized transform coefficients, but the differential pixel values between the original and predicted pixel values. Therefore, considering the statistical characteristics of residual data in lossless video coding, we newly design each entropy coding method based on the conventional entropy coders in H.264/AVC. From the experimental result, we have verified that the proposed method provides not only positive bit-saving of 8% but also reduced computational complexity compared to the current H.264/AVC lossless coding mode.

Improved Context-Based Adaptive Binary Arithmetic Coding over H.264/AVC for Lossless Depth Map Coding

The depth map, which represents three-dimensional (3D) information, is used to synthesize virtual views in the depth image-based rendering (DIBR) method. Since the quality of synthesized virtual views highly depends on the quality of depth map, we encode the depth map under the lossless coding mode. The original context-based adaptive binary arithmetic coding (CABAC) that was originally designed for lossy texture coding cannot provide the best coding performance for lossless depth map coding due to the statistical differences of residual data in lossy and lossless depth map coding. In this letter, we propose an enhanced CABAC coding mechanism for lossless depth map coding based on the statistics of residual data. Experimental results show that the proposed CABAC method provides approximately 4% bit saving compared to the original CABAC in H.264/AVC.

Multi-View Video and Multi-Channel Audio Broadcasting System

In recent years, various multimedia services have become available and the demand for realistic multimedia systems is growing rapidly. The multi-view video and multi-channel audio are expected to satisfy the user demand for realistic multimedia services. In this paper, we present a new broadcasting system incorporating multi-view video and multi-channel audio over IPTV and MPEG-21 DIA. The proposed system includes data acquisition, camera calibration, data encoding and decoding, transmission, intermediate view reconstruction, and multi-view display and multi-channel audio play. In this paper, we discuss the main features of multi-view video and multi-channel audio.

Improved CABAC design in H.264/AVC for lossless depth map coding

The depth map represents three-dimensional (3D) data and is used for depth image-based rendering (DIBR) to synthesize virtual views. Since the quality of synthesized virtual views highly depends on the quality of the depth map, we encode the depth map by lossless coding mode. However, context-based adaptive binary arithmetic coding (CABAC) for the H.264/AVC standard does not guarantee the best coding performance for lossless depth map coding because CABAC was originally designed for lossy coding. In this paper, we propose an improved coding method of CABAC for lossless depth map coding considering the statistical properties of residual data from lossless depth map coding. Experimental results show that the proposed CABAC method provides approximately 4.3% bit saving, compared to the original CABAC in H.264/AVC.

New CAVLC design for lossless intra coding

The context-based adaptive variable length coder (CAVLC) in H.264/AVC is not appropriate for lossless video coding because it was designed for lossy video coding. Since statistical characteristics of residual data in lossy and lossless coding are quite different, we design a new VLC table for the number of non-zero coefficients and an adaptive scheme for VLC table selection in level coding for lossless intra coding. Experimental results show that the proposed CAVLC scheme provides approximately 10% bit saving, compared to the original CAVLC scheme in H.264/AVC.

Efficient Level and Zero Coding Methods for H.264/AVC Lossless Intra Coding

Since H.264/AVC was designed mainly for lossy video coding, the entropy coding methods in H.264/AVC are not appropriate for lossless video coding. Based on statistical differences of residual data in lossy and lossless coding, we develop efficient level and zero coding methods. Therefore, we design an improved context-based adaptive variable length coding (CAVLC) scheme for lossless intra coding by modifying the relative entropy coding parts in H.264/AVC. Experimental results show that the proposed method provides approximately 6.8% bit saving, compared with the H.264/AVC FRExt high profile.

New CAVLC encoding algorithm for lossless intra coding in H.264/AVC

Context-based adaptive variable length coding (CAVLC) of H.264/AVC was originally designed for quantized transform coefficients in lossy video coding, and as such does not yield adequate performance in lossless video coding. In this paper, we propose an improved CAVLC for lossless intra coding. Considering statistical differences of residual data in lossy and lossless coding, we design a new CAVLC encoding algorithm. Experimental results show that the proposed method provides approximately 7.6% bit savings, compared to the current H.264/AVC FRExt high profile.

VLC table prediction algorithm for CAVLC in H.264 using correlation and statistics of mode information

The recent H.264 video coding standard adopted context-based adaptive variable length coding (CAVLC) as the entropy coding tool. By combining adaptive variable length coding (VLC) with context modeling, we can achieve a high degree of redundancy reduction. However, CAVLC in H.264 has a problem that correctness of VLC table prediction is low. In this paper, we propose a new VLC table prediction algorithm using both the correlation of coding mode and the statistics of mode distribution in both intra and inter frames. Experimental results show that the proposed algorithm reduces the bit rate by 0.94% on average.

Efficient Differential Pixel Value Coding in CABAC for H.264/AVC Lossless Video Compression

Since context-based adaptive binary arithmetic coding (CABAC) as the entropy coding method in H.264/AVC was originally designed for lossy video compression, it is inappropriate for lossless video compression. Based on the fact that there are statistical differences of residual data between lossy and lossless video compression, we propose an efficient differential pixel value coding method in CABAC for H.264/AVC lossless video compression. Considering the observed statistical properties of the differential pixel value in lossless coding, we modified the CABAC encoding mechanism with the newly designed binarization table and the context-modeling method. Experimental results show that the proposed method achieves an approximately 12% bit saving, compared to the original CABAC method in the H.264/AVC standard.