Rethinking the Joint Optimization in Video Coding for Machines: A Case Study

Changsheng Gao, Zhuoyuan Li, Li Li, Dong Liu, Feng Wu

Abstract: In this work, we investigate the joint optimization strategy in the scenario of video coding for machines (VCM). We formulated two kinds of joint optimization strategies, Opt_JA and Opt_JH , and compared them with the separate optimization strategy Opt_S. The three optimization strategies are illustrated in Fig. 1 . In Opt_S , we separately train the feature compression network with mean squared error (MSE). In Opt_JA , we optimize all modules jointly toward the person re-identification task. In Opt_JH , only the aggregation module and feature compression module are jointly optimized. The feature compression consists of two fully-connected (FC) layers and two batch normalization (BN) layers. Specifically, we set five compression ratios (CR): 256, 128, 64, 32, and 16.