We introduce a development method and its result based on 'platform architecture' to reduce development time and cost. For evaluating this method, a digital high-speed video camera, which can be operated at 2,000 frames per second (FPS) with 1M-pixels resolution and up to over 100,000 FPS with reduced resolution, has been developed using the platform architecture. First, we show technology improvements for high-speed image sensors and high-speed video cameras and discuss customer requirements. Next, functional structures based on the platform architecture are shown. For this high-speed video camera, a CMOS image sensor, which has high sensitivity and can be driven at 2,000FPS with full resolution of 1024 by 1024 pixels (1M-pixels), has also been developed. In addition, another high-speed video camera, which has 512 by 512 pixels with 2000FPS, has been developed following the above camera using the same "platform" and most of its components. We describe technical specifications of these high-speed video cameras for the results.