Codecs

Codec types and constants for video, audio, and subtitle media

Overview

Mediabunny provides comprehensive codec support through type definitions and constants for video, audio, and subtitle formats.

Types

MediaCodec

Union type of all known media codecs (video, audio, and subtitle).

type MediaCodec = VideoCodec | AudioCodec | SubtitleCodec;

VideoCodec

Union type of all known video codecs.

type VideoCodec = typeof VIDEO_CODECS[number];

Possible values:

• 'avc' - H.264/AVC
• 'hevc' - H.265/HEVC
• 'vp9' - VP9
• 'av1' - AV1
• 'vp8' - VP8

AudioCodec

Union type of all known audio codecs.

type AudioCodec = typeof AUDIO_CODECS[number];

Possible values:

• Compressed codecs: 'aac', 'opus', 'mp3', 'vorbis', 'flac', 'ac3', 'eac3'
• PCM codecs: 'pcm-s16', 'pcm-s16be', 'pcm-s24', 'pcm-s24be', 'pcm-s32', 'pcm-s32be', 'pcm-f32', 'pcm-f32be', 'pcm-f64', 'pcm-f64be', 'pcm-u8', 'pcm-s8', 'ulaw', 'alaw'

SubtitleCodec

Union type of all known subtitle codecs.

type SubtitleCodec = typeof SUBTITLE_CODECS[number];

Possible values:

• 'webvtt' - WebVTT subtitles

Constants

VIDEO_CODECS

List of known video codecs, ordered by encoding preference.

const VIDEO_CODECS: readonly ["avc", "hevc", "vp9", "av1", "vp8"];

Source: codec.ts:34

AUDIO_CODECS

List of known audio codecs, ordered by encoding preference.

const AUDIO_CODECS: readonly [
  "aac", "opus", "mp3", "vorbis", "flac", "ac3", "eac3",
  "pcm-s16", "pcm-s16be", "pcm-s24", "pcm-s24be",
  "pcm-s32", "pcm-s32be", "pcm-f32", "pcm-f32be",
  "pcm-f64", "pcm-f64be", "pcm-u8", "pcm-s8",
  "ulaw", "alaw"
];

Source: codec.ts:81

PCM_AUDIO_CODECS

List of known PCM (uncompressed) audio codecs, ordered by encoding preference.

const PCM_AUDIO_CODECS: readonly [
  "pcm-s16", "pcm-s16be", "pcm-s24", "pcm-s24be",
  "pcm-s32", "pcm-s32be", "pcm-f32", "pcm-f32be",
  "pcm-f64", "pcm-f64be", "pcm-u8", "pcm-s8",
  "ulaw", "alaw"
];

Source: codec.ts:46

NON_PCM_AUDIO_CODECS

List of known compressed audio codecs, ordered by encoding preference.

const NON_PCM_AUDIO_CODECS: readonly [
  "aac", "opus", "mp3", "vorbis", "flac", "ac3", "eac3"
];

Source: codec.ts:67

SUBTITLE_CODECS

List of known subtitle codecs, ordered by encoding preference.

const SUBTITLE_CODECS: readonly ["webvtt"];

Source: codec.ts:90

Codec details

Video codecs

avc (H.264/AVC)

Advanced Video Coding, widely supported baseline codec. Good for compatibility.

Encoding preference: 1st (highest)

hevc (H.265/HEVC)

High Efficiency Video Coding. ~40% more efficient than AVC.

Encoding preference: 2nd

vp9

VP9 codec. Similar efficiency to HEVC, commonly used for web video.

Encoding preference: 3rd

av1

AV1 codec. ~60% more efficient than AVC, royalty-free.

Encoding preference: 4th

vp8

VP8 codec. Slightly less efficient than AVC.

Encoding preference: 5th (lowest)

Audio codecs

Compressed audio codecs

• aac: Advanced Audio Coding, widely supported
• opus: Modern codec optimized for interactive speech and music
• mp3: MPEG-1 Audio Layer 3, legacy but universally supported
• vorbis: Open-source alternative to AAC
• flac: Free Lossless Audio Codec
• ac3: Dolby Digital (AC-3)
• eac3: Enhanced AC-3 (Dolby Digital Plus)

PCM audio codecs

Uncompressed pulse-code modulation formats:

• pcm-s16/pcm-s16be: 16-bit signed (little/big endian)
• pcm-s24/pcm-s24be: 24-bit signed (little/big endian)
• pcm-s32/pcm-s32be: 32-bit signed (little/big endian)
• pcm-f32/pcm-f32be: 32-bit float (little/big endian)
• pcm-f64/pcm-f64be: 64-bit float (little/big endian)
• pcm-u8: 8-bit unsigned
• pcm-s8: 8-bit signed
• ulaw: μ-law encoding
• alaw: A-law encoding

Usage example

import { VIDEO_CODECS, AUDIO_CODECS, type VideoCodec } from 'mediabunny';

// Check if a codec is supported
const codec: VideoCodec = 'avc';
if (VIDEO_CODECS.includes(codec)) {
  console.log('Codec is supported');
}

// Iterate through all video codecs
for (const codec of VIDEO_CODECS) {
  console.log(`Video codec: ${codec}`);
}

// Work with audio codecs
const audioCodec = AUDIO_CODECS[0]; // 'aac'