Reading: VRCNN-BN — Variable-filter-size Residue-learning Convolutional Neural Network with Batch Normalization (Codec Filtering)

Outperforms VDSR, DCAD, VRCNN, and Residual-VRN, Over 13% BD-Rate Reduction

Sik-Ho Tsang
3 min readMay 19, 2020
VRCNN-BN as Out-of-loop Filter

In this story, Variable-filter-size Residue-learning Convolutional Neural Network with Batch Normalization (VRCNN-BN), by Shanghai University, and Shanghai University of Engineering Science, is briefly described. It is a post-processing out-of-loop filter instead of an in-loop filter. This is a paper in 2020 ACCESS which is an open access journal with high impact factor of 4.098. (Sik-Ho Tsang @ Medium)

Outline

  1. VRCNN-BN Network Architecture
  2. Experimental Results

1. VRCNN-BN Network Architecture

VRCNN-BN Network Architecture
Detailed Information About the VRCNN-BN
  • ReLU is used except the last layer.
  • Different from VRCNN, VRCNN-BN uses Batch Normalization (BN) which is originated from Inception-v2.
  • (It has been a discussion on video restoration whether BN should be applied or not. Some with BN obtains better results, some without BN obtains better results…)
  • MSE is used as loss function.
  • Separate models are used for luma and chroma respectively.
  • For each QP, a separate model is also trained. Thus, there are in total 8 models.

2. Experimental Results

2.1. CS-PSNR as Evaluation

  • Color-Sensitive PSNR (CS-PSNR) is used for evaluation to calculate BD-rate:
  • where PY=0.685, PU=0.137, PV=0.178, which are the percentages of the color components.
  • HM16.19 is used.

2.2. BD-Rate

BD-Rate (%) Under RA and AI Configurations
BD-Rate (%) Under LDP and LDB Configurations
  • For luma, BD-rate reduction, on CS-PSNR, of 10.3%, 8.9%, 13.1% and 11.8% for RA, AI, LDP and LDB configurations are obtained.

2.3. Visual Quality

Visual Quality (Maybe it is better to see the figure in the original paper…. lol)
  • Ringing artifacts are reduced by using VRCNN-BN.

2.4. SOTA Comparison

BD-Rate (%) Under AI Configuration
  • As shown above, VRCNN-BN outperforms VRCNN by large margin.
BD-Rate (%) Under RA, AI, LDP, LDB Configurations
BD-Rate (%) Under Unknown Configurations Using CIF Format Videos
  • VRCNN-BN outperforms VDSR by large margin.

During the days of coronavirus, let me have a challenge of writing 30 stories again for this month ..? Is it good? This is the 27th story in this month. 3 stories to go. Thanks for visiting my story..

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Sik-Ho Tsang
Sik-Ho Tsang

Written by Sik-Ho Tsang

PhD, Researcher. I share what I learn. :) Linktree: https://linktr.ee/shtsang for Twitter, LinkedIn, etc.

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