Kivoza

Guide 03 / local processing

How conversion stays in the browser.

The HEIC converter uses your browser to read, decode, render, preview, and package results. Knowing the path makes its privacy and its limits easier to understand.

Kivoza guide · local processing and failures

The boundary: the selected file is read as a browser File object. The conversion flow does not send the image contents to a Kivoza conversion endpoint.

What happens in the tab

01 / CHECK

The page checks that the file is non-empty, within the 20 MB per-file limit, and has a supported HEIC / HEIF container signature.

02 / DECODE

The local decoder reads the bytes and renders the first supported image frame into browser memory. The decoded pixel count is checked against the 40 megapixel limit.

03 / RENDER

The pixels are drawn to a canvas. JPG output uses the selected quality and a white background for transparent pixels; PNG output can keep alpha transparency.

04 / DOWNLOAD

The result is held as a local object URL for the preview and download. A ZIP, when requested, is assembled in the same browser tab.

Why a file can fail

A file can be a valid-looking name without being a supported HEIC or HEIF image. Renamed JPGs, empty files, damaged containers, codecs outside the decoder build, and files above the size or pixel limits are reported as individual failures.

Decoding also needs working memory. A phone or laptop with little free memory may fail on a large image even when the file is under the stated limit. Try one file, close other heavy tabs, or use a smaller source.

What “local” does and does not mean

Local processing means the image bytes used for conversion stay in the browser session. The converter still needs to request its page code and decoder resources so the browser can run the tool. The page currently uses no advertising or analytics script, and it does not require an account or a conversion cookie.

Your browser can still keep normal HTTP cache data, and any message you send to [email protected] is handled by your email provider. Do not include a private photo in a support message unless you intend to share it.

When to retry

  • Use Retry after a temporary memory failure or after closing other heavy tabs.
  • Remove a file and add it again if you changed the output format or JPG quality.
  • Use the preview and downloaded file to verify the result before you delete the original.
  • Contact support with the file extension, size, browser, and visible error text. The file itself is optional.

For an action-focused walkthrough, read the iPhone HEIC to JPG guide. For output tradeoffs, read the JPG or PNG guide.