International organisation for standardisation organisation internationale de normalisation

5.16.4Scans

5.16.4.1.1.1.1.1.1JCTVC-H0284 Non-CE11: Unification of transform coefficient coding [C.-W. Hsu, T.-D. Chuang, Y.-W. Huang, S. Lei (MediaTek)]

This proposal was to use 4x4 sub-block scanning instead of diagonal scanning, also for 8x8 TUs. No noticeable change was reported in BD bit rate results.

Horizontal/vertical scans were not changed.

H0145, H0524, and H0399 also proposed the same.

Decision: Adopt the replacement of the 8x8 diagonal scan by 4x4 diagonal sub-scans.

5.16.4.1.1.1.1.1.2JCTVC-H0662 Non-CE11: Cross check of Mediatek proposal JCTVC-H0284 [J. Kim, C. Kim (LGE)] [late]

5.16.4.1.1.1.1.1.3JCTVC-H0145 Non-CE11: Harmonization of 8x8 TU residual scan [C. Rosewarne, M. Maeda (Canon)]

Beyond H0284, this also replaces horizontal/vertical scans of 8x8 blocks by horizontal/vertical scans in 4x4 sub-blocks. This loses 0.3% in AI, and 0.1% in RA&LD cases.

One opinion was expressed that the horizontal/vertical scans are simple to implement (unlike the diagonal), and that therefore the harmonization may not be too important for these.

5.16.4.1.1.1.1.1.4JCTVC-H0595 Cross-check of Canon harmonization of 8x8 TU residual scan (JCTVC-H0145) [J. Sole (Qualcomm)] [late]

This was the same as H0284.

5.16.4.1.1.1.1.1.5JCTVC-H0524 Extending 4×4 sub-block diagonal scan to 8×8 TU [J. Kim, C. Kim, J Chen, J. Sole, W. Chien, M. Karczewicz, B. Jeon (Qualcomm)]

5.16.4.1.1.1.1.1.6JCTVC-H0698 Crosscheck of JCTVC-H0524 on extending 4×4 sub-block diagonal scan to 8×8 TU (JCTVC-H0524) [J. Kim, M. Kim (KAIST)] [late 02-03]