Audio & Video: the guide

ffmpeg in your browser: convert, trim, compress, extract frames, concatenate, burn subtitles - all locally. Entry point: https://lab.stsqz.com/audioconvert; for deep syntax reference see /manual.

Quick start

The page gives you a command-line input and a parameter panel. The most common conversion is a single line:

-i input.mp4 -c:v libx264 -preset veryfast -crf 23 -c:a aac output.mp4

• -crf sets quality: lower means better quality and bigger files; 18-28 is the usual range
• To change the container without re-encoding, add -c copy - it finishes in seconds

Don't feel like memorizing parameters? Use the task templates on the page: compress, transcode, burn subtitles, change frame rate and more ship as ready-made commands - pick one, adjust the filenames, run it.

Multiple files and the queue

The drop zone takes many files at once, and you can keep adding more. The command names which input to process; batch jobs run one after another, each with its own download when done.

Common tasks

Shrinking file size

-i input.mp4 -c:v libx264 -preset veryfast -crf 28 -c:a aac -b:a 128k output.mp4

Want it smaller still? Drop the audio bitrate to 96k (the -b:a 96k template does exactly that).

Extracting audio

-i input.mp4 -vn -c:a libmp3lame -q:a 4 output.mp3

Making a GIF

-i input.mp4 -vf fps=12,scale=480:-2 -loop 0 output.gif

Burning subtitles

-i input.mp4 -vf subtitles=sub.srt -c:v libx264 -preset veryfast -crf 24 -c:a copy sub_out.mp4

Drag the subtitle file in together with the video; SRT works as-is. Export the SRT from Speech to Text, come back here, and burn - a complete local subtitle pipeline.

Good to know

• The browser build of ffmpeg has no libvpx (the webm encoder), so webm output errors out - that's an engine limit
• Big files take time depending on your machine; leave the page open while it works
• Everything listed in the parameter panel is verified to work with the current engine - just pick and run
• First use loads the engine core; tasks can't start until the progress bar completes

Division of labor with /manual

This page is the "grab and go" cheatsheet; the /manual handbook has 20 systematic chapters: full parameter tables, filters, troubleshooting, and a glossary. Use this page for the everyday, open that one when you're stuck.