Which method is primarily used to compress video data in digital broadcasting?

Video encoding techniques are the primary method used to compress video data in digital broadcasting. These techniques involve converting raw video footage into a format that reduces file size while maintaining quality, enabling efficient storage and transmission over various channels. Common video encoding methods include standards like H.264, H.265 (HEVC), and VP9, which utilize algorithms to optimize the data by removing redundancies, both spatially and temporally, thus allowing for more effective streaming and broadcasting.

The other options, while related to aspects of video and broadcasting, do not directly address the compression of video data in the same manner. Velocity modulation generally refers to a technique used in specific broadcasting contexts, often related to signal modulation rather than direct video data compression. Waveform coding involves mapping the analog audio signals but is less about video data compression directly. Frame averaging focuses on improving the visual quality by averaging multiple frames, which can enhance clarity but does not effectively address the compression of video data itself like encoding techniques do.