Mega Pixel Processor

Features

• Conversion at any size: XISF, FITS, TIFF and BigTIFF natively, plus PNG, JPEG, WebP, AVIF and JPEG XL, with no ceiling at classic TIFF's 4 GB limit. TIFF output takes the full option set: 8, 16 and 32-bit unsigned or 32 and 64-bit float samples, None, LZW, Deflate or PackBits compression with a horizontal predictor, strips or tiles, and classic TIFF or BigTIFF container.
• Astrometry travels with the image: the astrometric solution is carried natively where the container supports it (FITS, XISF) and as a JSON sidecar where it doesn't (TIFF, PNG, DZI).
• Zoomable publishing: export any image as a DZI (Deep Zoom) tile pyramid with a ready-made interactive HTML viewer. Plain static files you can host anywhere, no platform required.
• BigTIFF for PixInsight: a file-format module that replaces PixInsight's built-in TIFF module, reading and writing TIFF and BigTIFF from the ordinary Open and Save As dialogs, with its own options dialog covering sample format, compression, container, strips or tiles, alpha, ICC profile, resolution and text tags.

CLI Coming soon

The command-line tool is not yet available for download; it will be released alongside the GitHub repository. A taste of what it looks like: convert a mosaic to BigTIFF for Photoshop, or publish it as a self-hosted zoomable web page.

mpp convert mosaic.xisf mosaic.tif --bit-depth u16 --compression deflate --tiled
mpp publish mosaic.xisf site/ --title "Veil Nebula"

Comprehensive CLI documentation will be available on GitHub when the tool is released.

PixInsight Integration

Mega Pixel Processor ships as MegaPixelProcessor, a file-format module that provides the TIFF format (classic TIFF and BigTIFF, read and write) in place of PixInsight's built-in TIFF module. It is delivered from the same update repository as Mega Merge Mosaic, and the two are selected independently in the update dialog. Documentation is included with the module.

Install from the update repository

If you already have the Astrometrical repository set up for Mega Merge Mosaic, skip to step 3.

1. Open Resources → Updates → Manage Repositories.
2. Click Add, paste the repository URL:
   https://tools.astrometrical.com/pixinsight/ Copy
3. Accept, then run Resources → Updates → Check for Updates. Make sure Mega Pixel Processor module is ticked and apply.
4. Restart PixInsight. The TIFF format is now provided by Mega Pixel Processor, and .tif, .tiff, .btf and .tf8 files open and save through it.

Only want Mega Merge Mosaic? Untick the Mega Pixel Processor module in the update dialog and nothing changes for you.

Confirm Mega Pixel Processor is handling TIFF

Either check tells you which module is active:

• Open Format Explorer and select TIFF. The module should be listed as MegaPixelProcessor, and the description should read Mega Pixel Processor: TIFF/BigTIFF (read+write). The built-in module lists itself as TIFF instead.
• Save any image as a .tif. Mega Pixel Processor presents its own Astrometrical-branded TIFF Options dialog, with Container and Layout sections the built-in dialog does not have.

Switching between the two TIFF modules

The swap is fully reversible, and you can go back and forth as often as you like. Only one can be installed at a time, so the sequence is always uninstall, restart, install, restart:

1. Open Process → Modules → Manage Modules and uninstall whichever TIFF module is active: TIFF (built-in) or MegaPixelProcessor. Restart PixInsight.
2. Open Process → Modules → Install Modules and point it at PixInsight's bin directory, where both module files live.
3. Select the one you want, TIFF-pxm for the built-in module or mpp-pxm for Mega Pixel Processor, and install it. Restart PixInsight.

Never delete the built-in module's files. Both TIFF-pxm and its .xsgn signature file must be present for it to reinstall. Switching back to the built-in module does not cause the updater to nag you: it only mentions Mega Pixel Processor again when a new version is released, and you can untick it then.

Installed without disabling the built-in module first?

No harm done. PixInsight downloaded the module but refused to register it, so it reports an install failure and Mega Pixel Processor is not active. As far as PixInsight is concerned the module is installed but not registered, so Check for Updates will not offer it again. Fix it by hand: uninstall the built-in TIFF module as described above, restart, then follow the switching steps to install mpp-pxm from the bin directory and restart once more.

Beta channel

Testers can point PixInsight at a beta repository to receive pre-release builds ahead of the stable channel. Use it in place of the stable repository above, not alongside it; having both installed is not supported.

Beta builds are unpolished, so expect rough edges. Stick with the stable repository unless you're specifically testing.

Swapping TIFF modules: what changes

Everything else the built-in TIFF dialog offered is available: all five sample formats, LZW and Deflate compression, ICC profile embedding, alpha channels, resolution and the three text tags.