Guides, tutorials, and tips for creators, editors, and everyday users
An SRT file is plain-text subtitles. Open it here to see what is inside, then learn how to use it on Windows, Mac, iPhone, Android and TV, and why accents or timing break.
A VTT file is WebVTT subtitles: plain text built for browsers. Open yours here, see whether the header and timestamps are right, and learn how to play, convert or edit it on any device.
An ASS file is Advanced SubStation Alpha subtitles: text with styling, fonts and positioning. Open yours here, then learn which players render it properly, why the styling vanishes, and how to convert it.
A .sub file is one of three different subtitle formats. Open yours here to find out which, then learn how to play it, why it drifts out of sync, and how to convert it to SRT.
An SBV file is YouTube's caption format, and it is plain text. Open yours here, read it, and convert it to SRT or VTT so it works in VLC, on other platforms and in editors.
An OPUS file is compressed audio, usually a WhatsApp or Telegram voice note. Play it here, see whether your browser supports it, and learn how to open, convert or transcribe it on Windows, Mac, iPhone and Android.
An OGG file is compressed audio, usually Vorbis, sometimes an Opus voice note from Telegram. Play it here, see whether your browser supports it, and learn how to open or convert it on every device.
An M4A file is Apple-style compressed audio, usually an iPhone voice memo or an iTunes track. Play it here, then learn how to open it on Windows, Android and in Audacity, and why some M4A files cannot be converted at all.
An AAC file is compressed audio without a container: the raw stream that M4A files wrap. Play it here, then learn which players refuse the bare stream, why it cannot be scrubbed, and how to convert it to MP3 or M4A.
A FLAC file is lossless compressed audio, CD quality at half the size. Play it here, then learn why iTunes and Music refuse it, which car stereos skip it, and when converting to MP3 or ALAC makes sense.
A WMA file is Windows Media Audio, Microsoft's format from the CD-ripping era. Play it here, then learn why Macs, iPhones and browsers refuse it, which WMA files are DRM-locked for good, and how to convert the rest to MP3.
An AIFF file is uncompressed audio, Apple's equivalent of WAV. Play it here, then learn why some Windows and Android players refuse it, why DJs prefer it to WAV, and when to convert it to WAV, FLAC or MP3.
An MKV file is a video container that can hold any codec, several audio tracks and embedded subtitles. Play it here, then learn which players open it, why QuickTime and Premiere refuse it, and how to remux it to MP4 without re-encoding.
A WEBM file is web video: what Chrome, Loom and most screen recorders produce. Play it here, then learn why QuickTime, iMovie and Premiere refuse it, why a recording shows no length, and how to convert it to MP4.
A MOV file is Apple's QuickTime video, and almost always an iPhone recording. Play it here, then learn why Windows shows a black screen on HEVC, how to fix the sideways video, and how to convert it to MP4.
An AVI file is a 1992 Windows video container, usually holding DivX or Xvid from the 2000s or raw footage from an old camera. Play it here, then learn why Apple refuses it, why a modern player shows a black screen, and how to convert it to MP4.
A HEIC file is an iPhone photo. See yours here, even in Chrome, then learn why Windows and most browsers refuse it, how to make the iPhone send JPG, and how to convert it.
A WEBP file is an image, the format websites now serve instead of JPG. Open yours here, then learn why Photoshop, older Office or an old Windows refuse it, and convert it to JPG or PNG.
A TIFF file is a high-quality image, usually a scan, a fax or a print-ready photo. Open yours here, then learn why browsers and some apps refuse it, how multi-page TIFFs work, and how to convert it to JPG, PNG or PDF.
A BMP file is an uncompressed Windows bitmap. Everything opens it; the real questions are why it is so big, why a website or a form rejects it, and how to convert it to PNG or JPG without losing anything.
An ICO file is a Windows icon or a website favicon: several sizes of the same image in one file. Open yours here, then learn why editors show only one size, how to turn a PNG into an ICO, and how to get a PNG back out.
An MD file is Markdown: plain text with a few symbols for headings, bold and lists. Open yours here, see it formatted, and learn which apps render it, why Notepad shows hash signs, and how to convert it to PDF, DOCX or HTML.
A GIF frame delay is a whole number of hundredths of a second, so the only rates it can express are 100/n. Ask for 30 and you get 33.33 — ten seconds of animation plays in nine. And the 12 fps GIF on your disk really alternates 80 ms and 90 ms.
Most waveform generators read one sample per pixel column — 0.01 % of a three-minute track. A full-scale tone draws as a flat line, the shape changes when you resize the image, and 360 full-scale drum hits vanish completely: 0 of 800 columns show one.
Averaging a cover returns a colour the cover does not contain — six saturated hues average to exactly grey. And white text clears the 4.5:1 readability threshold on only 36 % of colours, while choosing between white and black never drops below 4.58:1 across all 16,777,216 of them.
A ring drawn at the edge of a square avatar loses exactly half its width to the circular crop — 20 px measured back as 10, at every size. The fix is one subtraction, and the circle has already taken 21.46 % of the image before you start.
Splitting a 1170-pixel photo into four slides asks a canvas for a 292.5-pixel slice. It does not round — it resamples, and a measured 1-pixel edge fell from 255 of contrast to 32. Why that happens, and the arithmetic that avoids it.
Three guides put TikTok’s bottom margin at 250, 400 and 484 px. We measured it at 422 — plus what Shorts covers, why Reels could not be measured, and the 841×1360 box that survives all three.
The sizes YouTube actually renders a thumbnail at, measured in a browser rather than copied from a guide — plus the 2 MB limit that is only half true, and what the duration badge covers.
How the tap and hold (press and hold) trend works, why the effect breaks for most first attempts, and how it differs from the tap the post strip trend.
Full subtitle workflow for YouTube creators — from creating SRT files to uploading and translating subtitles for global reach.
Everything about the SRT format — structure, timing, creating files from scratch, and best practices for subtitle creation.
Complete guide to YouTube thumbnails — downloading competitor thumbnails, design best practices, and optimization tips.
How to translate your YouTube subtitles into multiple languages to grow your international audience.
Only the faint teaser shows, or nothing at all. The mobile app, PNG-32 exports, re-saves, chat apps and light mode, with the fix for each.
What to press on each device, why dark mode changes everything, and what to do when the hidden picture still refuses to show.
What the Japanese word means, how the old paper illusions relate to today's transparent PNG, and how to make one that works.
Pick the clip, set the start, a short duration, the frame rate and the width, and download. What each setting does to the file size, and which frame rates a GIF can really store.
A separate SRT or VTT file that viewers can switch off, or text burned into the picture that plays everywhere. How to get the file, fix its timing, translate it and use it either way.
Cut a 30-second M4R in the browser, then install it with GarageBand, Finder or iTunes for Windows. Length limits and the Android steps too.
Complete guide to working with PDFs online. Learn how to merge, split, compress, and handle common PDF tasks.
Understanding audio formats, when to use each one, and how to convert between them for free.
Image format guide — JPG vs PNG vs WebP, when to convert, quality tips, and optimization for web and print.
Everything about QR codes — types, business uses, WiFi sharing, contact cards, and best practices.
What is Markdown, how to use it, common syntax, and converting to PDF, Word, and HTML.
Why random passwords matter, how generators work, and best practices for password security.
Every free tool a YouTube creator needs — from subtitle creation and thumbnail grabbing to audio extraction and PDF management.
Accessibility, legal requirements, and best practices for adding subtitles to video content.
Complete beginner-friendly video editing workflow using free tools — from filming to publishing and repurposing.