File format guides

Reference guides with comparison tables and key facts, written by the team at ARTH.

• Image Formats Compared: HEIC, JPG, PNG, WebP, AVIF and GIFA clear comparison of the six most common image formats: compression, transparency, animation, browser support and when to use each.
• Audio Formats Explained: MP3, AAC, WAV, FLAC and OGGWhat the major audio formats are, how they differ in size and quality, and which one to choose for music, podcasts and editing.
• Video Container Formats Explained: MP4, MOV, MKV, WebM and GIFThe difference between a video container and a codec, and how MP4, MOV, MKV, WebM and GIF compare in compatibility and use.
• How Browser Based File Conversion Works: WebAssembly, FFmpeg and PrivacyHow websites can convert photos, PDFs, audio and video entirely on your device using WebAssembly, and what that means for privacy and speed.
• Why iPhones Save Photos as HEIC: History, Benefits and ProblemsThe history of HEIF and HEIC, why Apple adopted it in iOS 11, how much space it saves and why it causes compatibility problems.
• Lossless vs Lossy Compression: What You Keep and What You LoseA plain explanation of lossless and lossy compression across images, audio and video, with examples and guidance on when each matters.
• PDF Explained: History, Standards and How a PDF File WorksWhere the PDF format came from, how it became ISO 32000, what is inside a PDF file and how to merge, split and convert PDFs safely.
• A Privacy Checklist for Online File ConvertersEight questions to ask before you upload a photo, PDF or video to a free converter, and how local, in-browser tools remove most of the risk.
• Choosing File Formats for Web Performance: Images, Video and AudioPractical guidance for picking image, video and audio formats that keep web pages fast, from WebP and AVIF to MP4 and WebM.
• Glossary of File Conversion Terms: Codec, Container, Bitrate and MorePlain English definitions of the terms you meet when converting images, audio and video, from bitrate and sample rate to codec and container.