go-xmp
go-xmp is a native Go SDK for the Extensible Metadata Platform (XMP) as defined by the Adobe XMP Specification Part 1, Part 2 and Part 3, a.k.a ISO 16684-1:2011(E).
Features
Included metadata models
- XMP DublinCore (dc)
- XMP Media Management (xmpMM)
- XMP Dynamic Media (xmpDM)
- XMP Rights (xmpRights)
- XMP Jobs (xmpBJ)
- XMP Paged Text (xmpTPg)
- EXIF v2.3.1 (exif, exifEX)
- Adobe Camera Raw (crs)
- Creative Commons (cc)
- DJI Drones (dji)
- ID3 v2.2, v2.3, v2.4 (id3)
- iXML audio recorder (ixml)
- iTunes/MP4 (itunes)
- ISO/MP4 (mp4)
- Quicktime (qt)
- PhotoMechanic (pm)
- Tiff (tiff)
- Riff (riff)
- Photoshop (ps)
- PDF (pdf)
Metadata models available under commercial license
- ACES Image Metadata
- AEScart
- ARRI Camera Metadata
- ASC CDL
- EBU Broadcast WAV
- Getty Images
- IPTC Core 1.2, IPTC Extension 1.3, IPTC Video Metadata 1.0
- Plus Licensing Metadata
- SMPTE DPX Image Metadata
- SMPTE MXF Metadata
- OpenEXR Image Header Metadata
- XMP Media Production SDK (Universal Metadata Container)
Documentation
Installation
Install go-xmp using the "go get" command:
go get github.com/trimmer-io/go-xmp
The Go distribution is go-xmp's only dependency.
Examples
Benchmarks
go test ./test/ -bench=. -benchmem
goos: darwin
goarch: amd64
pkg: trimmer.io/go-xmp/test
BenchmarkUnmarshalXMP_5kB-8 5000 321524 ns/op 58071 B/op 1056 allocs/op
BenchmarkMarshalXMP_5kB-8 5000 270981 ns/op 61384 B/op 758 allocs/op
BenchmarkMarshalJSON_5kB-8 5000 338354 ns/op 91855 B/op 1023 allocs/op
BenchmarkUnmarshalJSON_5kB-8 5000 382196 ns/op 60387 B/op 1022 allocs/op
BenchmarkUnmarshalXMP_85kB-8 300 5152080 ns/op 902794 B/op 17779 allocs/op
BenchmarkMarshalXMP_85kB-8 300 4292143 ns/op 966356 B/op 12209 allocs/op
BenchmarkMarshalJSON_85kB-8 300 5378268 ns/op 1453004 B/op 16535 allocs/op
BenchmarkUnmarshalJSON_85kB-8 200 5512114 ns/op 880161 B/op 14497 allocs/op
XMP Marshal Benchmark using premiere-cc.xmp, a rather large xmpDM file with history, xmpMM:Pantry etc.
Compression Results 417 mean min max
-----------------------------------------------------------------------------
Original sizes 4013 (100.0) 918 (100.0) 86940 (100.0)
XMP sizes 3545 ( 90.4) 723 ( 52.3) 78325 (147.0)
XMP Gzip sizes 1177 ( 32.0) 369 ( 8.4) 8086 ( 61.3)
XMP Snappy sizes 1195 ( 32.5) 387 ( 8.4) 8104 ( 62.9)
JSON sizes 2147 ( 52.8) 389 ( 31.6) 65127 ( 91.7)
JSON Gzip sizes 889 ( 23.7) 209 ( 6.9) 7714 ( 50.5)
JSON Snappy sizes 907 ( 24.3) 227 ( 7.0) 7732 ( 50.6)
-----------------------------------------------------------------------------
XML->XMP times 371.674µs 74.091µs 4.816883ms
XMP->JSON times 234.785µs 36.91µs 4.517591ms
XMP->XML times 259.084µs 20.004µs 4.505254ms
XMP Gzip times 214.342µs 105.685µs 1.036886ms
XMP Gunzip times 59.948µs 19.924µs 285.113µs
XMP Snappy times 28.325µs 7.975µs 234.161µs
XMP Unsnappy times 25.841µs 7.899µs 195.265µs
JSON Gzip times 197.268µs 93.86µs 968.985µs
JSON Gunzip times 53.622µs 17.655µs 2.913516ms
JSON Snappy times 23.581µs 7.864µs 221.674µs
JSON Unsnappy times 37.215µs 7.856µs 398.361µs
Size matters when storing XMP in a database or sending documents over a network. Above is a quick comparison between common compression methods gzip and snappy regarding runtime and size for documents in the samples/ directory. What's also included is a comparison of the uncompressed documents in XMP/XML and XMP/JSON format. Original means the initial XMP document as stored in .xmp sidecar files. To be fair, some originals use padding, so the mean size distribution is larger than what go-xmp generated here because padding was turned off during write.
Contributing
See CONTRIBUTING.md.
License
go-xmp is available under the Apache License, Version 2.0.