line Checking LINE app video call quality (opens in new tab)
To optimize the LINE messenger’s communication performance, LY Corporation conducted an on-site call quality assessment in Thailand to analyze local network conditions and compare performance against rising competitors. The study concluded that while LINE offers superior visual clarity and higher bitrates than its rivals, this high-performance strategy requires a careful technical balance to prevent video freezing in unstable network environments. ### High Video Call Adoption in Thailand * Thailand exhibits the highest video call usage among LINE’s major markets, with video calls accounting for 30.43% of all 1:1 sessions—more than double the rate of Japan or Taiwan. * The surge in usage by competitors, specifically "Messenger A," has necessitated frequent benchmarking to maintain LINE’s market leadership and technical edge. * Thailand serves as the primary testing ground for any updates to video modules due to the local user base's preference for high-quality real-time visual communication. ### On-Site Quality Testing Methodology * The assessment was performed over five days by five engineers across high-traffic locations in Bangkok, such as Siam Paragon and Samron Market, using True and AIS 4G/5G networks. * Engineers focused on Quality of Service (QoS) metrics—including packet loss and jitter—to estimate the actual Quality of Experience (QoE) for users. * Baseline performance for LINE in Thailand was recorded at VGA resolution, with frame rates exceeding 20 FPS and an average latency of approximately 150ms. ### Bitrate Strategy and Performance Trade-offs * LINE utilizes a high-bitrate strategy, capping at 1Mbps on 5G and 600kbps on 4G, to deliver sharper, more defined images than Competitor A. * A "start-at-max" approach is used where LINE attempts to find and utilize the highest possible bitrate from the beginning of the call to ensure immediate high quality. * In contrast, competitors adopt a conservative bitrate strategy, starting low and increasing slowly to prioritize connection stability over visual fidelity. * The trade-off for LINE’s higher quality is an increased risk of "freezing"—defined as a single frame persisting for more than 200ms—when the network becomes congested or unstable. ### Technical Implications for Future Development * The relationship between bitrate and network stability remains a zero-sum trade-off; higher bitrates provide better clarity but increase the likelihood of packet delay and loss at the router level. * LINE’s engineering focus is directed toward optimizing the "initial bitrate" detection logic to ensure high quality without triggering network-induced lag in crowded urban environments. * Continuous tuning of the balance between peak visual performance and consistent playback remains the core challenge for maintaining service quality in the Thai market.