Fast motion vector re-estimation for transcoding MPEG-1 into MPEG-4 with lower spatial resolution in DCT-domain

Seo, Kwang-Deok; Kim, Jae-Kyoon

doi:10.1016/j.image.2003.11.001

Cited by 8 publications

(17 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The work in [9] exploited the overlapping property of consecutive prediction. As shown in Figure 6(a), the MC-DCT block, predicted by v 0 n + (1, 0), is displaced from B 0 by one pixel in the right.…”

Section: Efficient Methods For Extracting Mc-dct Block In Mvrmentioning

confidence: 99%

“…For the case B l 0 predicted by v 0 n + (−1, 0), B l 0 overlaps B 0 by 8 × 7 pixels and partially overlaps A 0 and A 2 (Figure 6(b)). To extract B l 0 , [9] proposes (14), where R T is DCT(R T ),…”

Section: Efficient Methods For Extracting Mc-dct Block In Mvrmentioning

confidence: 99%

“…(4) ACT-weighted. In this method, the distance between each vector and the rest is calculated as sum of the activity-weighted distances by (9). The activity is the squared or absolute sum of DCT coefficients, the number of nonzero DCT coefficients, or simply the DC value.…”

Section: Fast Motion Resampling (Fmr)mentioning

confidence: 99%

“…Based on brute-force motion compensation in DCT-domain (MC-DCT), FRNI can provide better quality than nonrefine motion vector and reduces the complexity. In DRS, it utilizes the filter for half-pixel motion vector in MC-DCT [8] and efficient method for extracting MC-DCT block [9,10] to further improve the performance. Two kinds of MVR algorithms in DRS are further designed for different architectures.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Video Transcoder in DCT-Domain Spatial Resolution Reduction Using Low-Complexity Motion Vector Refinement Algorithm

Tsai

Lin

2008

EURASIP J. Adv. Signal Process.

View full text Add to dashboard Cite

We address the topic of spatial-downscaling video transcoder in DCT-domain. The proposed techniques include the hierarchical fast motion resampling (HFMR) with accuracy motion resampling, the fast refinement for nonintegral (FRNI) motion vector (MV), and the dynamic regulating search (DRS) with low-complexity motion vector refinement. Two kinds of motion vector refinement algorithms in DRS are designed for different architectures and applications. Based on brute-force motion compensation in DCT-domain (MC-DCT), FRNI can provide better quality than nonrefine MV and reduce the complexity. DRS can utilize the filter for half-pixel MV in MC-DCT and it is an efficient method for extracting MC-DCT block to improve the performance further. From the experiments, the proposed algorithms can improve the entire quality and also reduce the complexity for DCTdomain video transcoder.

show abstract

Section: Efficient Methods For Extracting Mc-dct Block In Mvrmentioning

confidence: 99%

Section: Efficient Methods For Extracting Mc-dct Block In Mvrmentioning

confidence: 99%

Section: Fast Motion Resampling (Fmr)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Video Transcoder in DCT-Domain Spatial Resolution Reduction Using Low-Complexity Motion Vector Refinement Algorithm

Tsai

Lin

2008

EURASIP J. Adv. Signal Process.

View full text Add to dashboard Cite

show abstract

“…In [7], the problems associated with mapping motion vectors and MB-level data were addressed. Macroblock mode decision by reusing the pre-encoded information was discussed in [8] and [9]. However they are all designed for fixed-size block-based motion estimation, and they are not suitable for H.264 transcoding system because of the variable block-size motion estimation feature adopted in H.264.Several methods have been presented in literatures focusing on motion vectors mapping and motion vectors refinement problems for H.264 spatial down-sampling transcoding [10][11] [12].Zhang [10]proposed a mode mapping method, which was time-saving but had about 3 dB losses.…”

Section: Introductionmentioning

confidence: 99%

An Efficient H.264 Transcoder with Spatial Downscaling for Wireless Communications

Wang

2009

2009 5th International Conference on Wireless Communications, Networking and Mobile Computing

View full text Add to dashboard Cite

Wireless video communication is an important application supported by 3G mobile communication systems. Motivated by the wide adoption of H.264 and the demand of universal multimedia data access over wireless network, this paper presents a fast video transcoder , working entirely in the DCT-domain, to convert high quality H.264 bitstream into low bit rate stream with low spatial resolution for wireless video access, furthermore, a motion vector estimation algorithm based on mapping and merging process is proposed to utilize the original motion information to predict motion vectors for the downscaled video. Simulation results show that, compared with the conventional transcoder, the proposed method significantly reduces the transcoding complexity while maintaining comparable rate distortion performance.

show abstract

DCT Block Conversion for H.264/AVC Video Transcoding

Lee

Chung

2005

Euro-Par 2005 Parallel Processing

View full text Add to dashboard Cite

In H.264/AVC [1], integer transforms are applied instead of the 8×8 discrete cosine transform (DCT) of previous standards to avoid inverse transform mismatch problems. However, these transforms make it difficult to transcode the precoded video contents with the earlier video coding standards into H.264/AVC in DCT-domain, thus causing cascaded re-encoding in the pixel-domain. There are strong requests for an efficient way to solve this problem. In this paper, we propose a new conversion scheme from an 8×8 DCT block into four 4×4 DCT blocks in H.264/AVC. Experimental results show that the proposed scheme improves PSNR up to 0.1dB and a little computational complexity compared with the cascaded pixel-domain IDCT/DCT. Moreover, other DCT-domain transcoding methods are applicable based on our scheme.

show abstract

Fast motion vector re-estimation for transcoding MPEG-1 into MPEG-4 with lower spatial resolution in DCT-domain

Cited by 8 publications

References 22 publications

Video Transcoder in DCT-Domain Spatial Resolution Reduction Using Low-Complexity Motion Vector Refinement Algorithm

Video Transcoder in DCT-Domain Spatial Resolution Reduction Using Low-Complexity Motion Vector Refinement Algorithm

An Efficient H.264 Transcoder with Spatial Downscaling for Wireless Communications

DCT Block Conversion for H.264/AVC Video Transcoding

Contact Info

Product

Resources

About