用語集

ABR

Adaptive Bitrate Streaming

A streaming technique that dynamically adjusts video quality based on the viewer's network conditions.

AV1

AOMedia Video 1

A royalty-free video codec offering 30-50% better compression than H.265, developed by the Alliance for Open Media.

B-Frame

Bidirectional Predicted Frame

A video frame that references both preceding and following frames for highly efficient compression.

CBR

Constant Bitrate

A video encoding mode maintaining a fixed data rate throughout, providing predictable file sizes and bandwidth usage.

Container Format

Container Format (Multimedia Wrapper)

A file format that acts as a wrapper to hold one or more video, audio, subtitle, and metadata streams together in a single file, independent of the codecs used to encode those streams.

CRF

CRF (Constant Rate Factor)

A quality-based video encoding setting that automatically adjusts the bitrate to maintain a consistent visual quality throughout the entire video, allocating more data to complex scenes and less to simple ones.

H.265

High Efficiency Video Coding (HEVC)

A video codec offering ~50% better compression than H.264 at equivalent quality, used for 4K/8K content.

HDR10

High Dynamic Range 10

An open HDR standard using static metadata, 10-bit color depth, and Rec. 2020 color space for brighter displays.

Frame Rate

Frame Rate (Frames Per Second)

The number of individual still images (frames) displayed per second in a video, determining the smoothness of motion. Common frame rates include 24 fps (cinema), 30 fps (broadcast), and 60 fps (gaming and sports).

Transcoding

Transcoding (Format Re-encoding)

The process of converting a video or audio file from one codec or format to another by fully decoding the original and re-encoding it, typically to change the codec, bitrate, resolution, or container format.

Keyframe

Keyframe (Intra-Coded Frame)

A complete, self-contained frame in a video that stores the full image data without reference to other frames, serving as a reference point for surrounding frames that only store the differences.

Interlacing

Interlacing (Field-Based Video)

A legacy video scanning technique that displays each frame as two interleaved fields (odd lines first, then even lines), originally designed to reduce flicker on CRT displays while halving the bandwidth requirement.

Subtitle

Subtitle (Text Overlay Track)

Timed text displayed over video that provides dialogue, narration, or descriptive captions, either embedded within the video container file or provided as a separate text file.

Trimming

Trimming (Video Clip Extraction)

The operation of selecting a specific time range from a video and extracting or keeping only that segment, discarding the content before the start point and after the end point.

Muxing

Muxing (Multiplexing Streams)

The process of combining separate video, audio, subtitle, and metadata streams into a single container file, or the reverse operation of extracting individual streams from a container (demuxing).

GOP

Group of Pictures

A sequence of video frames starting with a keyframe, defining the compression structure between keyframes.

Deinterlacing

Video Deinterlacing

The process of converting interlaced video into progressive frames for smooth display on modern screens.

Chroma Key

Chroma Key Compositing

A technique replacing a solid-color background (green screen) with another image or video.

Two-Pass Encoding

Two-Pass Video Encoding

A video encoding method that analyzes the video in a first pass to optimize bitrate allocation in the second.

Color Grading

Video Color Grading

The process of altering the color and tone of video footage to achieve a desired visual mood or style.

Stabilization

Video Stabilization

A technique that reduces unwanted camera shake and motion in recorded video footage.

Bitrate (Video)

Video Bitrate

The amount of video data processed per second, directly affecting quality and file size of the output.

Dolby Vision

Dolby Vision HDR

A proprietary HDR format using dynamic metadata to optimize brightness and color on a scene-by-scene basis.

I-Frame

Intra-coded Frame

A self-contained video frame that does not reference other frames, serving as a random access point in the stream.

P-Frame

Predicted Frame

A video frame encoded as differences from the previous reference frame, providing moderate compression.

HLG

Hybrid Log-Gamma

An HDR standard that is backward-compatible with SDR displays, developed by BBC and NHK for broadcast use.

Rec. 709

ITU-R BT.709 Color Space

The standard color space for HD video, defining the color primaries and transfer function used by most displays.

VFR

Variable Frame Rate

A recording mode where the frame rate changes during capture, common in screen recordings and mobile video.

CFR

Constant Frame Rate

A video encoding where frames are evenly spaced at a fixed interval, preferred for editing and streaming compatibility.

VBR

Variable Bitrate

A video encoding mode that allocates more bits to complex scenes and fewer to simple ones for better quality per byte.

DASH

Dynamic Adaptive Streaming over HTTP

An adaptive streaming standard that breaks video into small HTTP-served segments at multiple quality levels.

HLS

HTTP Live Streaming

An Apple-developed adaptive streaming protocol using .m3u8 playlists and .ts segments, widely supported on the web.

Motion Estimation

Video Motion Estimation

An encoding technique that identifies movement between frames to efficiently compress video using motion vectors.

Video Codec

Software that compresses and decompresses video data (e.g. H.264, H.265/HEVC, VP9, AV1).

Timecode

Video Timecode

A sequence of numeric codes (HH:MM:SS:FF) assigned to each video frame for precise identification and synchronization.

Pillarboxing

Pillarbox Format

Adding black bars to the sides of a video to display 4:3 content in a 16:9 widescreen frame.

Proxy Editing

Proxy Video Editing

Editing with lower-resolution copies of footage for smoother playback, then relinking to the originals for final export.

LUT

Lookup Table

A color transformation preset that maps input color values to output values, used for color grading and correction.

Optical Flow

Optical Flow Interpolation

An AI-based method for generating new frames by analyzing pixel motion between existing frames for smooth slow-motion.

Rec. 2020

ITU-R BT.2020 Color Space

A wide color gamut standard for UHD/4K video, covering 75% of the visible color spectrum versus 36% for Rec. 709.

H.264

Advanced Video Coding (AVC)

The most widely used video codec, balancing compression efficiency with broad hardware and software compatibility.

Letterboxing

Letterbox Format

Adding black bars to the top and bottom of a video to display widescreen content in a narrower frame.

Frame Blending

Video Frame Blending

A technique that creates intermediate frames by blending adjacent frames to smooth slow-motion or speed changes.