Bitrate and resolution both relate to media file data, but resolution measures pixel detail while bitrate is the data used per second. A high resolution doesn't guarantee good quality if the bitrate is low, and a lower resolution with a good bitrate can look better than a poorly compressed high resolution video. The codec used also significantly impacts visual efficiency, with newer codecs like H.265 requiring less bandwidth for the same quality. High bitrates increase file size and bandwidth demands, potentially causing buffering for viewers. Adaptive Bitrate Streaming (ABR) addresses this by creating multiple video renditions at different resolutions and bitrates. A manifest file lists these renditions, and the player dynamically selects the best one based on the viewer's real-time network conditions and buffer status. This allows the video to adjust quality seamlessly, preventing interruptions. ABR algorithms primarily use throughput-based and buffer-based methods, often combined in hybrid approaches, to balance quality, stability, and rebuffer risk. Digital Rights Management (DRM) is employed to protect content from unauthorized copying and distribution. DRM encrypts media, requiring a decryption key from a license server after verifying user legitimacy and device authorization. Major DRM systems include Widevine, FairPlay, and PlayReady, with content often encrypted with multiple systems for broader platform compatibility. When a license is requested, the player sends a device-specific request to the license server, which verifies the request and returns an encrypted license containing the decryption key. This key is then decrypted locally by the device's Content Decryption Module (CDM) within a secure environment, preventing access to the raw key or video data. Different security levels exist within DRM systems, with premium content often requiring higher security tiers for playback.