Learn the formats
File Guides & Format Comparisons
Practical guides for image, audio, archive and subtitle formats, including conversion steps, quality tradeoffs and browser compatibility.
Choose a format before you convert
The best output is determined by where the file will be used. A web image, editable subtitle file, lossless audio master and compressed email attachment have different requirements. These guides explain the tradeoffs so conversion is a deliberate choice rather than an automatic extension change.
Check what the destination supports
Before processing a large batch, confirm the accepted format, maximum size, color or transparency requirements, audio codec, subtitle timing model or archive restrictions of the destination platform. Test one representative file first.
Preserve originals and verify outputs
Conversion can be irreversible. Keep the source file, review the result and check properties that matter—image dimensions, transparency, animation, audio duration, subtitle timing, archive contents and filenames—before replacing an established workflow.
Frequently asked questions
File guide FAQ
Are these guides only for zer.ai tools?
No. They explain format choices and common risks generally, then link to a relevant zer.ai tool when one is available.
Does converting a file always preserve quality?
No. Lossy formats can discard information, and changing formats may remove metadata, transparency, animation, styling or codec features.
Why do browser results differ?
Browsers and devices support different codecs and memory limits. The same unusual file profile may not decode identically everywhere.
Should I delete the original after conversion?
Keep the original until the output has been checked in its destination application and backed up appropriately.