Joint Video Experts Team (jvet) of itu-t sg 6 wp and iso/iec jtc 1/sc 29/wg 11

5Test material and test conditions (4)

Contributions in this category were discussed Thursday 19 April 1210–1255 (chaired by JRO).

JVET-J0052 Tencent test sequences for video coding development [J. Ye, X. Li, S. Liu, L. Wu, C. Xie, K. Liu, B. Wang, P. Liu, K. Dong, Y. Kuang, W. Feng (Tencent)]
This contribution was pPresented Thursday. 19 Aprilth 1210-–1230 (chaired by JRO).

This contribution describes 10 test sequences for the development of next generation video coding standard. Among them, there are 6 concert related sequence (1920x1080, 25 fps, 4:2:0), 2 eSports sequences (1920x1080, 30 fps, 4: 2: 0), and other 2 other eSports sequences (2176x1080, 30 fps, 4: 2: 0).

(eSports are gaming sequences.). It was asked if the copyright of the gaming sequences was owned by Tencent. This was initially confirmed (this confirmation was to be consideredis valid unless the proponents withdreaw it within 24 hours).

Sequences are available in the JVET ftp repository (candidate branch) and have been inspected by some experts. The following comments were made.

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  The sSequences are challenging in terms of RD measurement.
  
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  It was remarked that HD content with only 25 or 30fps appears quite uncommon.
  
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  It was also commented that the eSports sequences might require higher bit rates generally. In terms of application domain, the low delay test case might also be more relevant. As currently no specific test cases for screen content are defined, this would remain for further investigation in future testing.
  
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  Copyright conditions as provided in the document and attached to sequences appeared OK.
  
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  Further investigation of test sequences was to occur in the test material AHG.
  
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JVET-J0060 Surveillance class and CTC for video coding development [X. Ma, H. Zhang, S. Gao, H. Yang, J. Chen (Huawei), S. Chen, D. Wu (Hisilicon)]

This contribution was

Ppresented Thursday. 19 Aprilth 1235-–1255 (chaired by JRO and GJS).

Surveillance applications is were said to be very important for safety and security in daily life. The rapidly increasing data volume of surveillance sequences creates a great challenge to storing the content. In this proposal, 3 surveillance test sequences are proposed. And also, low delay test condition with random access point is proposed based on the actual surveillance application. It wais suggested to establish a surveillance class and use the recommended low delay test condition for video coding development.

The same sequences were available previously, but with a different subsampling phase for theof chroma. Only one sequence (Building Hall, which had used in CfE), reflects this by the name. Names should be changed – sequences are already available in the ftp site., 4:4:4 versions should also be made available.

All of these sequences are with a static camera, not extremely challenging.

The proposal also suggests to add an intra access period (every 2 seconds) in the low delay test condition.

It was also mentioned that fixed bit rate would also be desirable for certain applications, and rate control should be studied.

It was however discussed that our CTC cannot reflect any very specific application case. It would be easy to estimate how much additional rate would be required when an intra refresh would be inserted every x seconds.

It was agreed not to modify CTC in regard of intra refresh and fixed bit rate.

The test sequences had been provided before; this wais an offer for a new version that uses a different chroma format downconversion. The sequences are also available in 4:4:4 format. Some version(s) of the sequences had already been available in the JVET test sequence repository and were used in the CfE. It was commented that we should make sure to use a different naming for the new version to avoid confusion.

These all use static cameras.

JVET-J0051 Adaptive GOP structure with future reference picture in random access configuration [S. Lee, Y.-W. Chen, W.-J. Chien, M. Karczewicz (Qualcomm)]

This contribution was initially discussed Sunday 15 April 1715–1745 (chaired by JRO).

The contribution proposes a new prediction structure for random access configuration to maximize coding efficiency with one extra picture buffer in DPB buffer. The proposed scheme is similar to the conventional GOP structure, e.g. GOP 16 and can be applied to the sequences with intra periods being multiples of 16 while reportedly providing significant coding gains over GOP 16. The proposed prediction structure introduces −-4.3% BD-rate gain delta over relative to HM-16.18 with 97% and 100% encoding and decoding run time. The proposed prediction structure also introduces −-4.8% BD-rate gain delta over relative to JEM-7.1 with 101% and 100% encoding and decoding run time. It wais suggested to use the proposed prediction structure for random access configuration in the CTC for the development of the next generation video coding standard.

The structure likely introduces additional delay, because two I pictures need to be decoded before any B picture in between can start decoding.

Question: Could fast motion sequences have problems? Proponents say it is at least not the case for the CfP sequences.

After the discussion on Sunday, the proponents received more comments from other experts that the configuration might cause problems in operating a “true” RA mode with decent a reasonable delay, as i.

It would implicitly introduce another 64 frames of encoding delay.

It also seemed unclear whether the bitstream would be fully conforming in terms of buffering constraints.

No change of CTC was made in response to this contribution.

JVET-J0068 Crosscheck of JVET-J0051 Adaptive GOP structure with future reference picture [G. Li (Tencent)] [miss] [late]

The results provided by the proponents were verified.