Glossary
Media formats, codecs, containers, and processing explained
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PNG
Portable Network Graphics. Lossless raster image format supporting transparency (alpha channel). Great for graphics, logos, UI assets.
JPG / JPEG
Lossy raster image format optimized for photographs. Adjustable quality controls file size and artifacts.
WebP
Modern image format by Google. Supports lossy and lossless compression, plus alpha transparency and animations.
AVIF
Image format based on AV1 video codec. High compression efficiency and quality; supports HDR and transparency.
Alpha Channel
An additional channel in an image that stores per-pixel transparency (opacity).
Chroma Key
Technique to remove a specific color background (green/blue screen) from an image or video.
Background Removal (AI)
Automatic segmentation of the subject from the background using machine learning models.
GIF
Graphics Interchange Format. Limited to 256 colors. Often used for short looping animations; large file sizes compared to video.
MP4
Container format typically using H.264/AVC video and AAC audio. Widely compatible across devices and browsers.
WebM
Open media container commonly using VP8/VP9/AV1 video and Vorbis/Opus audio. Great for the web.
H.264 / AVC
Widely-used video codec balancing quality and size. Plays virtually everywhere, including older devices.
AV1
Next-gen royalty-free video codec with excellent compression. Heavier to encode; growing browser support.
CRF
Constant Rate Factor. Quality-based control for video encoding; lower CRF = higher quality and larger files.
Bitrate (Audio)
The number of bits per second used to encode audio. Higher bitrate generally means higher quality and larger files.
Sample Rate
Number of samples per second in audio (Hz). Common values: 44100 Hz, 48000 Hz.
Channels (Mono/Stereo)
Audio channel configuration. Mono: one channel. Stereo: two channels (left/right).
Pitch (Semitones)
Perceived frequency of sound. Shifting pitch in semitones raises or lowers notes without changing speed.
Tempo
Speed of audio playback (e.g., 0.5×–2×). Can be changed independently from pitch with time-stretching.
Time-stretching
Changing the duration (tempo) of audio without altering pitch.
Transcoding
Converting media from one format/codec/container to another.
Container
A file wrapper (e.g., MP4, WebM) that holds encoded audio/video streams and metadata.
Codec
Algorithm that encodes/decodes media streams (e.g., H.264, VP9, AAC, Opus).
Lossy Compression
Compression that discards some data to reduce size (JPG, MP3). Introduces artifacts at low quality.
Lossless Compression
Compression that preserves all original data (PNG, FLAC).
AAC
Advanced Audio Coding. Common lossy audio codec used in MP4 containers.
Opus
Modern audio codec optimized for interactive speech and music at low bitrates. Often used in WebM.
WAV
Uncompressed (or PCM) audio container. Large files, high fidelity.
MP3
Popular lossy audio format; broadly compatible across platforms and devices.
PCM
Pulse-Code Modulation. Raw uncompressed digital audio representation.
Color Space
Defines how color values map to real colors (sRGB, Display P3). Important for consistent rendering.
HDR
High Dynamic Range. Wider brightness and color gamut; supported by some modern formats (e.g., AVIF, HEVC).
Metadata (EXIF)
Embedded metadata in images (camera settings, orientation, GPS). Often removed to reduce size or for privacy.
Keyframe (Video)
Frame encoded without reference to other frames. More keyframes improve seeking but increase size.
Bit Depth
Number of bits per color channel (e.g., 8‑bit, 10‑bit). Higher depth allows smoother gradients and HDR.
Alpha Premultiplication
Technique where RGB values are multiplied by alpha for better compositing.
Downsampling / Resampling
Changing image or audio resolution/sample rate. Impacts quality and file size.
Frame Rate (FPS)
Frames per second in video. Common values: 24, 30, 60. Higher FPS = smoother motion and larger files.
Noise / Artifacts
Unwanted distortions from compression or processing (blocking, ringing, banding).
Transparency
Portions of an image/video that are fully or partially see-through, typically via alpha channel.
Clipping
Loss of detail when signal exceeds representable range (e.g., blown highlights, audio distortion).
Dynamic Range
Difference between quietest and loudest or darkest and brightest values. Larger range preserves detail.
Normalization
Adjusting audio gain to reach a target loudness without changing dynamics.