In the context of live streaming marketing, it is crucial for members of the supply chain to allocate resources not only to enhance product quality through quality improvement efforts but also towards marketing initiatives aimed at boosting sales. This paper focuses on a dual-channel supply chain comprising a brand vendor and a streamer and investigates the spillover effect of the live streaming channel on traditional channels and product goodwill. By analyzing the Stackelberg game and differential game, this study compares the optimal equilibrium strategy and equilibrium profit under two decentralized models: the brand vendor-dominated decentralized model and the streamer-dominated decentralized model, as well as the centralized decision-making model. Additionally, this paper presents the optimal strategy and profit function of the product goodwill trajectory for the brand vendor, streamer, and the entire supply chain, considering different spillover effects using numerical simulation. The analysis reveals that the level of quality improvement consistently increases over time, while the variation in product goodwill is more diverse. The optimal pricing of products is influenced by the market share of the channel with goods under the decision of the two decentralized models. Risk-averse brands tend to collaborate with waist and tail streamers to gain control over bargaining power, while risk-seeking brands often choose top streamers to distribute their goods when the market share of goods channels is significant. The overall profitability of the supply chain is influenced by consumers' preferences for quality and marketing.