Supported Formats

Source and focused tests establish the routes and decision boundaries used here. No current-platform codec readiness, interoperability, output quality, or production performance is claimed.

Purpose, audience, prerequisites, and expected result

Use this page to decide what kind of file to open and what kind of artifact to save. It is a beginner decision guide, not a second codec specification. The single detailed authority for extensions, sample precision, compression, metadata, sequence layouts, and current implementation limitations is File Formats.

You need a local source file or an active AfterNight image/sequence and a writable destination when saving. At the end, you should have selected a format for a stated purpose, checked its authoritative capability row, written to a new path, and reopened/verified the result when it matters.

Reachability and availability

Item	Current behavior
Path	Open with File > Open, the Open toolbar action, a recent-file entry, or supported local drag-and-drop. Save with File > Save as... or Image > Actions > Save File.... Export an active sequence with Image > Sequence > Export....
Enabled/visible when	Open is application-wide. Standard save needs an active image or sequence view. Sequence Export applies to an active sequence. Settings routes are application-wide.
Supported inputs/state	Astronomy/display stills, camera RAW acquisition stills, native SER and AfterNight image-list sequences, and recognized FFmpeg-backed video containers. Exact extensions and constraints live only in File Formats.
Outputs/side effects	Standard still files, sequences written frame by frame into the container the destination path names, or Sequence Export output. A successful standard save adds the written file to recent files and, when the view still shows what was written, clears its pending changes and records the written file as the view's source path.
Persistence	The last open/save directory is remembered. Settings > General stores the initial still save format; Settings > Export stores global still encoding/metadata preferences. Sequence Export stores its own format/codec choices.
External dependencies	The deployed still codecs (camera RAW through LibRaw, with a private RawSpeed build used where it is qualified for the file) and, for video decode/encode, the deployed FFmpeg libraries and codec support. A recognized container suffix does not prove that its stream can be decoded.

Before you start

Decide which artifact you are making:

Purpose	Beginner choice	Mandatory follow-up
Astronomy processing master	FITS or XISF	Check the authority's sample-type and metadata row, then reopen and inspect required headers.
External-editor handoff	TIFF	Check sample type and selected compression in the authority and Settings > Export.
Lossless display copy	PNG	Confirm the authority's precision conversion is acceptable; do not treat it as the only high-precision master.
Small sharing copy	JPEG	Accept lossy, reduced-precision delivery; keep a separate master.
Original camera acquisition	Camera RAW as input	Preserve the RAW source and save processed work in another format; AfterNight does not write camera RAW.
Undemosaiced colour filter array mosaic	FITS, XISF, or TIFF	These record the filter array; PNG and JPEG cannot, and a save refuses them.
Native planetary/lucky-imaging sequence	SER	Verify CFA/debayer state, sample layout, frame count, and timing after writing.
Reopenable frame manifest	AfterNight image list (.anseq)	Keep its referenced/sibling frame files with the manifest.
Delivery video	Sequence Export to its offered AVI/MP4/WebM output	Treat it as decoded/re-encoded delivery, not a science master; verify codec, geometry, FPS, and boundary frames.

Preserve every acquisition source. Use a new destination rather than relying on replacement: standard output replacement is not a backup workflow. Ensure the destination has enough free space, especially for high-precision stills, intermediate frame sets, SER, or raw AVI.

Procedure

1. Identify the source as a still, camera RAW, native sequence, image list, or video. Open File Formats and verify its exact extension, dependency, and input constraints before relying on it.
2. Open with File > Open (or a supported recent/drop route). Checkpoint: the load progress finishes and a still or sequence view opens. A suffix appearing in the chooser is only the first gate; a damaged file, unsupported camera variant, or unsupported video stream can still fail.
3. Work on the underlying image/sequence. Viewer Autostretch, selected channel, zoom, overlays, and masks are display state and are not flattened into a standard still save. Apply a processing operation only when you intend to change the pixels.
4. Choose the artifact purpose from the table above, then read that format's authoritative precision, compression, metadata, and dependency row. For a still, set any global defaults under Settings > General and Settings > Export before opening the save dialog.
5. For a still, or to write a sequence into another sequence file, use File > Save as... or Image > Actions > Save File.... Both routes prompt. Select a new path and ensure the suffix agrees with the intended codec; the suffix controls still codec dispatch, not merely the selected filter.
6. For a delivery/converted sequence, use Image > Sequence > Export... and review output family/codec, destination, FPS, CFA debayer, Autostretch, and resize choices. Checkpoint: controls lock while export runs and the progress/cancellation path is visible.
7. Wait for success before using the artifact. A cancelled or failed write is not a verified result. Preserve the original and inspect the error/progress message before retrying.
8. Reopen important output. For a still, check dimensions, channels, sample type, and required metadata. For a sequence, check family/container, frame count, geometry, sample/CFA state, FPS, and first/last frame. AfterNight does not automatically perform this verification or checksum the output.

Complete control and action reference

UI label/action	Type and unit	Default	Valid values/constraints	Effect	Enabled, hidden, or ignored rules	Trade-off or side effect	Scope	Persistence
File > Open / Open toolbar	File chooser; Ctrl+O	Last open directory	Supported still and sequence filters; there is no all-files filter, and a selection holding any unrecognized suffix is refused whole with Unsupported File Type	Dispatches by suffix to a still or sequence loader and opens progress; a colour-filter-array mosaic asks Open CFA file before it is shown	Application-wide	Recognition does not guarantee decoder/camera support	Selected local files	Directory remembered
Recent file / local drag-and-drop	Direct open action	—	Existing local paths accepted by the app's filter/path checks	Uses the shared open workflow	Recent entry or accepted drop required	A moved/missing recent file fails; unsupported drops are ignored/rejected	Selected paths	Successful loads update recents
File > Save as...	Prompted save action; Ctrl+Shift+S	Filename from the active view; clean-profile initial still format is TIFF	Active still, or a sequence written to SER, AVI, an image list (.anseq), MP4/MOV, MKV, or WebM	Writes the underlying data through the chosen suffix/container	Requires active view	May convert precision/metadata; a mosaic is refused for PNG and JPEG; existing-path replacement has no automatic backup	Active view	Directory, recents, pending state, and the view's source path updated on success
Image > Actions > Save File...	Alias action	Same as Save as...	Same constraints	Calls the same standard save workflow	Requires active image/sequence context	Same side effects as Save as...	Active view	Same
Image > Sequence > Export...	Sequence export dialog	Stored choices; current source provides defaults	Offered SER, raw AVI, MP4/H.264/H.265, or WebM/VP9 combinations and their constraints	Decodes and rewrites frames with optional CFA debayer, Autostretch, and resize	Active sequence; output path required; controls lock while running	Can change pixels, precision, geometry, timing representation, file size, and compatibility	Whole sequence	Export selections/path context persist as implemented
Settings > General default format	Global selector	TIFF on a clean profile	Current still save choices	Selects the initial still filter/suffix	A suffix typed in the dialog can select another codec	Does not retroactively convert existing data	Later still saves	Global setting
Settings > Export	Global option page	See File Formats	TIFF/XISF/JPEG/PNG and metadata preferences implemented by the save path	Supplies options to later standard still saves	The standard save dialog has no per-save option panel	Global choices can silently affect precision, compression, size, and metadata	Later still saves	Global settings

Behavior and state model

flowchart TD
    accTitle: File format decision flow
    accDescr: Identify the purpose, check the format authority, then open, save, or export and verify the result.
    Source[Choose input or output goal] --> Authority[Check File Formats]
    Authority -->|Open| Load[Decode by suffix]
    Load --> View[Still or sequence]
    View -->|Still or copy| Save[Standard Save as]
    View -->|Convert sequence| Export[Sequence Export]
    Save --> Verify[Reopen and check]
    Export --> Verify

Still codecs are selected by the final filename suffix, case-insensitively. A file-dialog filter does not override a conflicting typed suffix. Standard still save receives the underlying image data, not the viewer rendering. A successful save updates bookkeeping and, when the view still shows what was written, records the new file as the view's source path.

Standard sequence save reads every frame of the source sequence and writes it into the container the destination path names: SER, AVI, an image list, MP4 or MOV, MKV, or WebM. A path naming another container is refused before anything is written. Sequence Export is different: it offers its own output families and codecs, and optional debayer/stretch/resize and output codec constraints can change the result. Those exact transformations and known implementation limitations are documented only in Saving And Exporting and File Formats.

Inputs, outputs, and metadata

AfterNight accepts the current still and sequence families listed by the authoritative matrix. Camera RAW is acquisition input only. Standard still outputs are FITS, XISF, TIFF, PNG, or JPEG; sequence routes depend on the source family and the Export choices. Do not infer compatibility merely from a broad format name—check extension, channels/sample type, compression, metadata, camera/stream variant, and deployed dependencies.

FITS/XISF are the astronomy-oriented metadata paths; TIFF/PNG/JPEG carry a more limited EXIF subset when Embed EXIF is on; its date is never the moment of the save, and a FITS GAIN card is not written as its gain-control field. Every XISF property is read whole and saved back as the type it was - a number, a vector, a matrix - and the processing history a file carries is kept; when an XISF file's FITS keywords state no plate solution, a solution stored in its properties is read and the file opens solved.

A camera RAW opens under the RAW settings in effect when the open was asked for; it is decoded by LibRaw, or by a private RawSpeed build where that decoder is qualified for the file, with the same samples and metadata either way. Under Auto White Balance its balance is measured from the frame itself. A full-colour RAW frame, such as a linear DNG, opens with each colour in its own plane. An X-Trans RAW (Fujifilm RAF) opens in colour, demosaiced in camera RGB by the engine's X-Trans methods - the fast X-Trans estimate under the Bilinear setting, three-pass Markesteijn under every other. Only a camera RAW frame is turned as it opens, by its recorded orientation when Auto-rotate is on.

A save that narrows the samples rounds each to the nearest code. A signed image saved as XISF keeps its width, written as the unsigned representation of that width. Geometry-changing processing can make prior WCS/SIP invalid. Exact retained/generated fields, numeric conversions, source modification behavior, history behavior, naming, overwrite, and recovery are intentionally centralized in File Formats.

Performance and responsiveness

Open, standard save, and sequence export use progress/background work, but decode/encode time, memory, and disk use depend on dimensions, channels, sample type, compression, frame count, transformations, and deployed codecs. Lossless or uncompressed output can be much larger than a delivery copy. Prototype an unfamiliar sequence export to a new path and verify it before committing to a long run. This guide records no current production timing, memory peak, size ratio, or cross-application interoperability result.

Worked example

• Evidence mode: Source-and-test-derived.
• Starting state, actions, settings, checkpoints, result, and limitations:

Suppose a Quick Start integration is open and you need both a processing master and a sharing copy. First select FITS or XISF in the decision table, check its current row in File Formats, use Save as... with a new path, and reopen it to check dimensions, channels, sample type, and required astronomy metadata. Then create a separate PNG or JPEG delivery copy only after checking its precision and metadata consequences. The master and delivery copy have different jobs; the latter does not replace the former.

The implementation and focused tests establish the routing, conversions, and verification need, but no project-owned file was encoded/reopened. No actual size, fidelity, metadata interoperability, or visual result is claimed.

Warnings and limitations

• File Formats is the sole detailed compatibility authority. Do not copy its extension/precision tables into other pages.
• Camera RAW output is unsupported. Preserve the source and save processed data in a different format.
• A recognized video container does not guarantee support for its internal stream. Video/sequence export is not a precision-preserving science master.
• Display Autostretch, masks, annotations, zoom, and overlays are not flattened into a standard still save.
• Existing-file replacement is not a backup, and AfterNight does not automatically reopen or checksum saved/exported output. A still save replaces an existing file only once the new one is complete.
• Metadata support differs by family; pixel-write success does not by itself prove every optional metadata field was written.
• A standard Save of a video sequence decodes and re-encodes every frame into the container the path names; it is not a byte copy of the source. MPG and MPEG cannot be written; use Sequence Export to a new destination instead.
• An X-Trans mosaic cannot be saved as FITS, which states only a two-by-two pattern; save it as XISF or TIFF, or demosaic it first.
• A BITPIX = 64 FITS image opens as 64-bit floating point only when every stored integer fits within 2^53; one with a larger integer is refused, since a 64-bit float cannot hold it exactly. A palette TIFF and a white-is-zero grey TIFF are refused by name (a palette PNG opens in its own colours), and an XISF file whose pixel data fail their checksum is refused.

Troubleshooting

Symptom or exact error	Verified cause/enablement path	Recovery	Evidence source
A file appears in the chooser but does not open	The suffix passed the first filter/dispatch gate, but content, camera variant (a four-colour CMYG or CYGM sensor), stream, or deployed decoder is unsupported/damaged	Check the exact authority row; preserve the source and test a verified copy/transcode when appropriate	FileManager.cpp; ImageViewFiles.cpp; CodecIO.h; SequenceContainers.cpp
Save does not offer camera RAW	RAW is input-only	Save a processing master as FITS/XISF/TIFF and retain the RAW source	FilePolicies.cpp; RawCodec.h
Reopened output has different precision or channels	The chosen codec/export path converted an unsupported input representation	Use the authority matrix to select a retaining master format; repeat to a new path and verify	ImageViewFiles.cpp; FileSaveTest.cpp; engine codec tests
Saved image does not include the visible stretch/overlay	Standard save writes underlying pixels, not viewer display state	Apply the intended pixel process, or use an explicit delivery/export workflow	FileWorkflowRunner.cpp; ImageViewControl.cpp
Sequence Export action is unavailable	The active context is not a sequence	Activate/open a sequence view, then use Image > Sequence > Export...	menu/action wiring; ExportSequenceControl.cpp
Sequence Save is refused for the chosen path	The path names a container the product does not write (for example .mpg or .mpeg)	Choose SER, AVI, .anseq, MP4/MOV, MKV, or WebM, or use Sequence Export to a new path	SequenceContainers.cpp; SequenceCompanions.cpp; FileSaveTest.cpp
Output cannot be trusted after cancellation/failure	The write/export did not reach a verified success state	Preserve source, discard or quarantine the partial destination, inspect the error, then retry to a new path	FileWorkflowRunner.cpp; OutputTransaction.h; ExportSequenceWindowTest.cpp

Related workflow steps

Use First Launch to verify a known small input and Quick Start to produce a first linear master. Use Saving And Exporting for the complete task workflow and Sequence Export controls.

Use File Formats for every detailed compatibility decision. Sequences, Settings, and System Requirements explain the related application state, global preferences, and deployed-environment needs.

References and provenance

• The current source and focused tests establish the beginner decision path and current routing.
• File Formats is the single detailed authority and retains the codec/standard provenance, exact capability matrix, and known limitations.
• Saving And Exporting is the authoritative action-level workflow for standard save and Sequence Export.
• No separate external format/codec contract is asserted on this page.