README
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MPO Encoder/Decoder Library
Simple Go JPEG MPO (Multi Picture Object) Decoder and Encoder - Library and CLI Tool
The library and CLI can:
- Decode an MPO into individual JPEG frames.
- Encode multiple JPEG frames into a Baseline-MP MPO.
- Convert an MPO to a stereoscopic (side-by-side) JPEG.
- Create anaglyph images (red–cyan, cyan–red, red–green, green–red).
A Web UI for converting MPO to JPEG is available at:
https://donatstudios.com/MPO-to-JPEG-Stereo
Install CLI Tool
Binaries are available for Darwin (macOS), Linux and Windows on the release page:
https://github.com/donatj/mpo/releases
From Source
go install github.com/donatj/mpo/cmd/mpo2img@latest
go install github.com/donatj/mpo/cmd/img2mpo@latest
CLI Usage
mpo2img
Convert an MPO file to a stereoscopic JPEG or anaglyph image.
$ mpo2img -help
Usage: mpo2img <mpofile>
Convert a Multi-Picture Object (MPO) file to an image.
-format string
Output format [stereo|red-cyan|cyan-red|red-green|green-red] (default "stereo")
-help
Displays this text
-outfile string
Output filename (default "output.jpg")
img2mpo
encode multiple images into an MPO file.
$ img2mpo -help
Usage: img2mpo <imagefile> [<imagefile> ...]
Convert one or more images to a Multi-Picture Object (MPO) file.
Supported image formats: JPEG, PNG, GIF, BMP, TIFF, WebP
-help
Displays this text
-outfile string
Output filename (default "output.mpo")
-quality int
JPEG quality [0-100] (default 90)
WIP
Todo:
- Optimization
- Add more control over stereo/anaglyph
Documentation
¶
Overview ¶
Package mpo provides simple read and write support for Multi‑Picture Object (MPO) files, a format that stores two or more JPEG frames in a single byte stream, and is used in some 3D cameras.
The package is designed to be simple and easy to use, with a focus on extracting and writing the JPEG frames. It does not attempt to implement the full specification of the MPO format, but rather provides a basic set of functions to work with the most common use cases.
The package offers:
- DecodeAll – extract every JPEG frame present in an MPO.
- EncodeAll – write a Baseline‑MP MPO from a slice of image.Image.
- ConvertToStereo – merge the first two frames side‑by‑side.
- ConvertToAnaglyph – create red/cyan or similar anaglyphs.
EncodeAll produces only the subset required for a Baseline‑MP file: the first frame is flagged as the representative image and is given MP type 0x00030000. DecodeAll imposes no such restriction and simply returns every JPEG it finds.
Specification references:
- CIPA DC‑X007:2012 – Multi‑Picture Format (MPF) https://www.cipa.jp/std/documents/e/DC-007-2012_E.pdf
- ISO/IEC 10918‑1 – JPEG Baseline coding and marker layout.
- JFIF 1.02 – APP0/JFIF segment details.
Offsets in the MP Image List are measured relative to the TIFF endian marker inside the APP2/MPF segment, as required by DC‑X007 §5.2.3.3. The code relies only on the Go standard library and is safe for pure‑Go builds.
Index ¶
Constants ¶
const ( // RedCyan is Red on left eye, cyan on right RedCyan colorType = iota // CyanRed is Cyan on left eye, red on right CyanRed // RedGreen is Red on left eye, green on right RedGreen // GreenRed is Green on left eye, red on right GreenRed )
Variables ¶
var ErrInconsistentBounds = errors.New("anaglyph images must be the same size")
ErrInconsistentBounds indicates that not all images within the MPO file were found to be the same size, which is a requirement for the anaglyph conversion.
var ErrInvalidImageCount = errors.New("anaglyph conversion only supports 2 images")
ErrInvalidImageCount indicates that incorrect number of images were found during the anaglyph conversion process.
var ErrNoImages = errors.New("no images found in mpo image")
ErrNoImages indicates that no images were found in the specified file.
var ErrUnsupportedColorType = errors.New("unsupported color type")
ErrUnsupportedColorType indicates that the color type requested is not supported by the anaglyph conversion process.
Functions ¶
func DecodeConfig ¶
DecodeConfig returns the color model and dimensions of an MPO image without decoding the entire image.
TODO Optimize this - possibly just falling back to jpeg.DecodeConfig
Types ¶
type MPO ¶
MPO represents the likely multiple images stored in a MPO file.
func (*MPO) ConvertToAnaglyph ¶
ConvertToAnaglyph converts an MPO to the anaglyph format specified by ct colorType constant and returns the resulting image.
ErrInconsistentBounds is returned if the images within the MPO are not the same size. ErrInvalidImageCount is returned if the number of images in the MPO is not exactly 2. ErrUnsupportedColorType is returned if the color type requested is not supported.
func (*MPO) ConvertToStereo ¶
ConvertToStereo converts an MPO to a StereoScopic image
Source Files
Directories