With the rapid advancement of public information dissemination technology, an increasing number of public venues, such as malls, stations, and airports, are facing complex crowd dynamics and information dissemination needs. To address these challenges more effectively, this study introduces a smart advertising system based on the $RK3399Pro$ embedded platform. This system not only serves primary information display purposes but also incorporates security surveillance and crowd counting functions. $Specifically:1$. Given the security needs of public places, we've integrated a network communication module and OV13850 camera into the advertising system for real-time surveillance.2. The system, leveraging the hardware decoding capabilities of the video processor and using FFmpeg transcoding, supports $4K$ video playback encoded with H.265-hevc, ensuring high-definition and latency-free visuals.3. To address data collection in high-footfall areas, we designed a crowdcounting feature by integrating YOLOv7 and DeepSORT algorithms. Experimental results indicate that the system maintains a refresh rate of $25FPS$ when playing videos of $3840\times 2160$ resolution encoded in H.265 format, ensuring smooth visuals. Surveillance videos, after optimized encoding, are reduced to a fifth of their original size, significantly saving storage space. Moreover, in multiple crowd counting tests, the system achieved an impressive recognition accuracy rate of 92.2%, underlining its utility and stability.