Metadata: Fix XMP body serial and add tiff: field fallbacks #2260

Read the standard exifEX:BodySerialNumber property, which ExifTool and
Adobe emit; the previous exifEX:SerialNumber matched no compliant XMP
sidecar and silently fell through to aux:SerialNumber.

Add deprecated TIFF-schema fallbacks still emitted by some writers:
tiff:Software (Software), tiff:ImageDescription (Description), and
tiff:Copyright (Copyright).

internal/meta/testdata/xmp/README.md

@@ -23,20 +23,21 @@ After editing a fixture:
 
 ## Synthetic Fixture Index
 
-| File                        | Purpose                                                                                                                                   |
-|-----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------|
-| `software-only.xmp`         | `xmp:CreatorTool` (Software). Single-tag fixture for the simplest accessor.                                                               |
-| `gps-time-combined.xmp`     | `exif:GPSTimeStamp` as a single combined ISO 8601 / RFC 3339 datetime — the spec-canonical encoding for `TakenGps`.                       |
-| `gps-time-split.xmp`        | Legacy split form: `exif:GPSDateStamp` + `exif:GPSTimeStamp`. Some older writers emit this; secondary `TakenGps` fallback.                |
-| `time-offsets-subsec.xmp`   | `exif:OffsetTimeOriginal/OffsetTime/OffsetTimeDigitized` cascade plus `exif:SubSecTimeOriginal` joined into `TakenAt`.                    |
-| `notes-usercomment.xmp`     | `exif:UserComment` as `lang-alt` (`<rdf:Alt>` with `x-default` + `en` + `de`). Confirms reader prefers `x-default`.                       |
-| `xmpdm-creationdate.xmp`    | `xmpDM:CreationDate` — secondary fallback for `CreatedAt` (rare; emitted by Adobe Premiere/After Effects).                                |
-| `subject-seq.xmp`           | `dc:subject` as `<rdf:Seq>` instead of `<rdf:Bag>`. Confirms reader handles both list types.                                              |
-| `aux-only.xmp`              | Adobe `aux:` namespace — `OwnerName`, `Lens`, `LensID`, `LensSerialNumber`, `SerialNumber`, `Firmware`. Legacy Lightroom/ACR.             |
-| `exifex-camera-lens.xmp`    | EXIF 2.3 for XMP `exifEX:` namespace — `LensMake`, `LensModel`, `SerialNumber` (= EXIF BodySerialNumber), `PhotographicSensitivity`, etc. |
-| `gpano-360.xmp`             | Google Photo Sphere — `GPano:ProjectionType = equirectangular` plus required dimension fields.                                            |
-| `multi-rdf-description.xmp` | Bug 2 demonstration: four sibling `<rdf:Description>` blocks each declaring a different namespace. Tests that XPath walks all blocks.     |
-| `alt-edge-cases.xmp`        | `<rdf:Alt>` shapes that real writers don't always produce: no `x-default` (only `de`/`en`), missing `xml:lang`, duplicate `x-default`.    |
+| File                        | Purpose                                                                                                                                |
+|-----------------------------|----------------------------------------------------------------------------------------------------------------------------------------|
+| `software-only.xmp`         | `xmp:CreatorTool` (Software). Single-tag fixture for the simplest accessor.                                                            |
+| `gps-time-combined.xmp`     | `exif:GPSTimeStamp` as a single combined ISO 8601 / RFC 3339 datetime — the spec-canonical encoding for `TakenGps`.                    |
+| `gps-time-split.xmp`        | Legacy split form: `exif:GPSDateStamp` + `exif:GPSTimeStamp`. Some older writers emit this; secondary `TakenGps` fallback.             |
+| `time-offsets-subsec.xmp`   | `exif:OffsetTimeOriginal/OffsetTime/OffsetTimeDigitized` cascade plus `exif:SubSecTimeOriginal` joined into `TakenAt`.                 |
+| `notes-usercomment.xmp`     | `exif:UserComment` as `lang-alt` (`<rdf:Alt>` with `x-default` + `en` + `de`). Confirms reader prefers `x-default`.                    |
+| `xmpdm-creationdate.xmp`    | `xmpDM:CreationDate` — secondary fallback for `CreatedAt` (rare; emitted by Adobe Premiere/After Effects).                             |
+| `subject-seq.xmp`           | `dc:subject` as `<rdf:Seq>` instead of `<rdf:Bag>`. Confirms reader handles both list types.                                           |
+| `aux-only.xmp`              | Adobe `aux:` namespace — `OwnerName`, `Lens`, `LensID`, `LensSerialNumber`, `SerialNumber`, `Firmware`. Legacy Lightroom/ACR.          |
+| `exifex-camera-lens.xmp`    | EXIF 2.3 for XMP `exifEX:` namespace — `LensMake`, `LensModel`, `BodySerialNumber`, `PhotographicSensitivity`, etc.                    |
+| `tiff-fields.xmp`           | Deprecated TIFF-schema fallbacks — `tiff:Software`, `tiff:ImageDescription` (lang-alt), `tiff:Copyright` (lang-alt).                   |
+| `gpano-360.xmp`             | Google Photo Sphere — `GPano:ProjectionType = equirectangular` plus required dimension fields.                                         |
+| `multi-rdf-description.xmp` | Bug 2 demonstration: four sibling `<rdf:Description>` blocks each declaring a different namespace. Tests that XPath walks all blocks.  |
+| `alt-edge-cases.xmp`        | `<rdf:Alt>` shapes that real writers don't always produce: no `x-default` (only `de`/`en`), missing `xml:lang`, duplicate `x-default`. |
 
 ## Source Notes
 

internal/meta/testdata/xmp/synthetic/exifex-camera-lens.xmp

@@ -9,7 +9,7 @@
    <exifEX:LensMake>SyntheticLens Co.</exifEX:LensMake>
    <exifEX:LensModel>SL 50mm f/1.4</exifEX:LensModel>
    <exifEX:LensSerialNumber>SL-50-987654</exifEX:LensSerialNumber>
-   <exifEX:SerialNumber>SC1-BODY-123456</exifEX:SerialNumber>
+   <exifEX:BodySerialNumber>SC1-BODY-123456</exifEX:BodySerialNumber>
    <exifEX:PhotographicSensitivity>800</exifEX:PhotographicSensitivity>
    <exifEX:SensitivityType>2</exifEX:SensitivityType>
    <exifEX:RecommendedExposureIndex>800</exifEX:RecommendedExposureIndex>

internal/meta/testdata/xmp/synthetic/tiff-fields.exiftool.txt

@@ -0,0 +1,27 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<rdf:RDF xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'>
+
+<rdf:Description rdf:about='internal/meta/testdata/xmp/synthetic/tiff-fields.xmp'
+  xmlns:et='http://ns.exiftool.org/1.0/' et:toolkit='Image::ExifTool 13.50'
+  xmlns:ExifTool='http://ns.exiftool.org/ExifTool/1.0/'
+  xmlns:System='http://ns.exiftool.org/File/System/1.0/'
+  xmlns:File='http://ns.exiftool.org/File/1.0/'
+  xmlns:XMP-x='http://ns.exiftool.org/XMP/XMP-x/1.0/'
+  xmlns:XMP-tiff='http://ns.exiftool.org/XMP/XMP-tiff/1.0/'>
+ <ExifTool:ExifToolVersion>13.50</ExifTool:ExifToolVersion>
+ <System:FileName>tiff-fields.xmp</System:FileName>
+ <System:Directory>internal/meta/testdata/xmp/synthetic</System:Directory>
+ <System:FileSize>651 bytes</System:FileSize>
+ <System:FileModifyDate>2026:07:07 10:13:16+00:00</System:FileModifyDate>
+ <System:FileAccessDate>2026:07:07 10:13:16+00:00</System:FileAccessDate>
+ <System:FileInodeChangeDate>2026:07:07 10:13:16+00:00</System:FileInodeChangeDate>
+ <System:FilePermissions>-rw-r--r--</System:FilePermissions>
+ <File:FileType>XMP</File:FileType>
+ <File:FileTypeExtension>xmp</File:FileTypeExtension>
+ <File:MIMEType>application/rdf+xml</File:MIMEType>
+ <XMP-x:XMPToolkit>PhotoPrism Synthetic Fixture</XMP-x:XMPToolkit>
+ <XMP-tiff:Software>TiffSoftware 1.0</XMP-tiff:Software>
+ <XMP-tiff:ImageDescription>A tiff image description</XMP-tiff:ImageDescription>
+ <XMP-tiff:Copyright>Copyright 2026 Example Org</XMP-tiff:Copyright>
+</rdf:Description>
+</rdf:RDF>

internal/meta/testdata/xmp/synthetic/tiff-fields.xmp

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<x:xmpmeta xmlns:x="adobe:ns:meta/" x:xmptk="PhotoPrism Synthetic Fixture">
+ <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
+  <rdf:Description rdf:about=""
+    xmlns:tiff="http://ns.adobe.com/tiff/1.0/">
+   <tiff:Software>TiffSoftware 1.0</tiff:Software>
+   <tiff:ImageDescription>
+    <rdf:Alt>
+     <rdf:li xml:lang="x-default">A tiff image description</rdf:li>
+    </rdf:Alt>
+   </tiff:ImageDescription>
+   <tiff:Copyright>
+    <rdf:Alt>
+     <rdf:li xml:lang="x-default">Copyright 2026 Example Org</rdf:li>
+    </rdf:Alt>
+   </tiff:Copyright>
+  </rdf:Description>
+ </rdf:RDF>
+</x:xmpmeta>

internal/meta/xmp_document.go

@@ -120,20 +120,29 @@ var (
 		mustCompile("//photoshop:Headline"),
 	}
 
-	// xmpDescriptionChain: dc:description Alt-language fallback.
+	// xmpDescriptionChain: dc:description → tiff:ImageDescription, each with
+	// the lang-alt fallback. tiff:ImageDescription is the deprecated TIFF-schema
+	// equivalent still emitted by some writers.
 	xmpDescriptionChain = chainXPath{
 		mustCompile("//dc:description/rdf:Alt/rdf:li[@xml:lang='x-default']"),
 		mustCompile("(//dc:description/rdf:Alt/rdf:li)[1]"),
 		mustCompile("//dc:description[not(rdf:Alt)]"),
+		mustCompile("//tiff:ImageDescription/rdf:Alt/rdf:li[@xml:lang='x-default']"),
+		mustCompile("(//tiff:ImageDescription/rdf:Alt/rdf:li)[1]"),
+		mustCompile("//tiff:ImageDescription[not(rdf:Alt)]"),
 	}
 
-	// xmpRightsChain: dc:rights Alt-language → xmpRights:WebStatement.
-	// WebStatement is a URL, not free text, but the embedded path uses
-	// the same fallback.
+	// xmpRightsChain: dc:rights Alt-language → tiff:Copyright Alt-language →
+	// xmpRights:WebStatement. tiff:Copyright is the deprecated TIFF-schema
+	// copyright text; WebStatement is a URL, not free text, but the embedded
+	// path uses the same fallback.
 	xmpRightsChain = chainXPath{
 		mustCompile("//dc:rights/rdf:Alt/rdf:li[@xml:lang='x-default']"),
 		mustCompile("(//dc:rights/rdf:Alt/rdf:li)[1]"),
 		mustCompile("//dc:rights[not(rdf:Alt)]"),
+		mustCompile("//tiff:Copyright/rdf:Alt/rdf:li[@xml:lang='x-default']"),
+		mustCompile("(//tiff:Copyright/rdf:Alt/rdf:li)[1]"),
+		mustCompile("//tiff:Copyright[not(rdf:Alt)]"),
 		mustCompile("//xmpRights:WebStatement"),
 	}
 
@@ -144,8 +153,12 @@ var (
 		mustCompile("//xmpRights:UsageTerms[not(rdf:Alt)]"),
 	}
 
-	// xmpSoftwareChain: xmp:CreatorTool.
-	xmpSoftwareChain = chainXPath{elemOrAttr("xmp:CreatorTool")}
+	// xmpSoftwareChain: xmp:CreatorTool → tiff:Software (deprecated TIFF-schema
+	// equivalent still emitted by some writers).
+	xmpSoftwareChain = chainXPath{
+		elemOrAttr("xmp:CreatorTool"),
+		elemOrAttr("tiff:Software"),
+	}
 
 	// xmpDocumentIDChain: xmpMM:OriginalDocumentID (asset-stable) →
 	// xmpMM:DocumentID (per-derivative) → dc:identifier (legacy).
@@ -203,10 +216,10 @@ var (
 		elemOrAttr("xmpDM:CreationDate"),
 	}
 
-	// xmpCameraSerialChain: exifEX:SerialNumber (= EXIF
-	// BodySerialNumber) → aux:SerialNumber.
+	// xmpCameraSerialChain: exifEX:BodySerialNumber (EXIF 0xA431, the property
+	// ExifTool and Adobe emit) → aux:SerialNumber (legacy Adobe).
 	xmpCameraSerialChain = chainXPath{
-		elemOrAttr("exifEX:SerialNumber"),
+		elemOrAttr("exifEX:BodySerialNumber"),
 		elemOrAttr("aux:SerialNumber"),
 	}
 
@@ -366,13 +379,13 @@ func (doc *XmpDocument) Title() string {
 }
 
 // Description returns the caption / image description.
-// Priority: dc:description (Alt/x-default → first rdf:Alt entry → bare text).
+// Priority: dc:description (Alt/x-default → first rdf:Alt entry → bare text) → tiff:ImageDescription.
 func (doc *XmpDocument) Description() string {
 	return SanitizeCaption(xmpDescriptionChain.firstNonEmpty(doc.doc))
 }
 
 // Copyright returns the rights statement.
-// Priority: dc:rights (Alt/x-default → first rdf:Alt entry → bare text) → xmpRights:WebStatement.
+// Priority: dc:rights (Alt/x-default → first rdf:Alt entry → bare text) → tiff:Copyright → xmpRights:WebStatement.
 // WebStatement is a URL approximation of the rights text but matches the embedded path's behavior.
 func (doc *XmpDocument) Copyright() string {
 	return SanitizeString(xmpRightsChain.firstNonEmpty(doc.doc))
@@ -456,7 +469,7 @@ func (doc *XmpDocument) TimeOffset() string {
 }
 
 // CameraSerial returns the camera body serial number.
-// Priority: exifEX:SerialNumber (= EXIF BodySerialNumber 0xA431) →
+// Priority: exifEX:BodySerialNumber (EXIF 0xA431) →
 // aux:SerialNumber (legacy Adobe, still emitted by Lightroom).
 func (doc *XmpDocument) CameraSerial() string {
 	return SanitizeString(xmpCameraSerialChain.firstNonEmpty(doc.doc))
@@ -597,7 +610,7 @@ func (doc *XmpDocument) License() string {
 }
 
 // Software returns the application that wrote the file.
-// Priority: xmp:CreatorTool (single-link).
+// Priority: xmp:CreatorTool → tiff:Software.
 func (doc *XmpDocument) Software() string {
 	return SanitizeString(xmpSoftwareChain.firstNonEmpty(doc.doc))
 }

internal/meta/xmp_document_test.go

@@ -363,12 +363,41 @@ func TestXmpDocument_Software(t *testing.T) {
 		doc := loadXmp(t, "testdata/xmp/synthetic/software-only.xmp")
 		assert.Equal(t, "PhotoPrism Synthetic Fixture 1.0.0", doc.Software())
 	})
+	t.Run("FallsBackToTiffSoftware", func(t *testing.T) {
+		// tiff-fields.xmp carries only tiff:Software (no xmp:CreatorTool).
+		doc := loadXmp(t, "testdata/xmp/synthetic/tiff-fields.xmp")
+		assert.Equal(t, "TiffSoftware 1.0", doc.Software())
+	})
 	t.Run("EmptyWhenAbsent", func(t *testing.T) {
 		doc := loadXmp(t, "testdata/fstop-favorite.xmp")
 		assert.Equal(t, "", doc.Software())
 	})
 }
 
+func TestXmpDocument_Description(t *testing.T) {
+	t.Run("FallsBackToTiffImageDescription", func(t *testing.T) {
+		// tiff-fields.xmp carries only tiff:ImageDescription (no dc:description).
+		doc := loadXmp(t, "testdata/xmp/synthetic/tiff-fields.xmp")
+		assert.Equal(t, "A tiff image description", doc.Description())
+	})
+	t.Run("EmptyWhenAbsent", func(t *testing.T) {
+		doc := loadXmp(t, "testdata/xmp/synthetic/software-only.xmp")
+		assert.Equal(t, "", doc.Description())
+	})
+}
+
+func TestXmpDocument_Copyright(t *testing.T) {
+	t.Run("FallsBackToTiffCopyright", func(t *testing.T) {
+		// tiff-fields.xmp carries only tiff:Copyright (no dc:rights).
+		doc := loadXmp(t, "testdata/xmp/synthetic/tiff-fields.xmp")
+		assert.Equal(t, "Copyright 2026 Example Org", doc.Copyright())
+	})
+	t.Run("EmptyWhenAbsent", func(t *testing.T) {
+		doc := loadXmp(t, "testdata/xmp/synthetic/software-only.xmp")
+		assert.Equal(t, "", doc.Copyright())
+	})
+}
+
 func TestXmpDocument_DocumentID(t *testing.T) {
 	t.Run("DigikamPrefersOriginalDocumentID", func(t *testing.T) {
 		// digiKam writes all three IDs; the chain must pick
@@ -592,14 +621,20 @@ func TestApexToSeconds(t *testing.T) {
 }
 
 func TestXmpDocument_CameraSerial(t *testing.T) {
-	t.Run("PrefersExifEXSerialNumber", func(t *testing.T) {
-		// Synthetic exifEX fixture writes both exifEX:SerialNumber and
-		// (no aux:SerialNumber). Modern fallback wins.
+	t.Run("PrefersExifEXBodySerialNumber", func(t *testing.T) {
+		// Synthetic exifEX fixture writes exifEX:BodySerialNumber and no
+		// aux:SerialNumber. Modern property wins.
 		doc := loadXmp(t, "testdata/xmp/synthetic/exifex-camera-lens.xmp")
 		assert.Equal(t, "SC1-BODY-123456", doc.CameraSerial())
 	})
+	t.Run("ReadsRealExifToolBodySerialNumber", func(t *testing.T) {
+		// canon_eos_6d.xmp is an ExifTool-written sidecar carrying the
+		// standard exifEX:BodySerialNumber property.
+		doc := loadXmp(t, "testdata/canon_eos_6d.xmp")
+		assert.Equal(t, "033024001432", doc.CameraSerial())
+	})
 	t.Run("FallsBackToAuxSerialNumber", func(t *testing.T) {
-		// canon_eos_6d has aux:SerialNumber but no exifEX:SerialNumber.
+		// aux-only.xmp has aux:SerialNumber but no exifEX:BodySerialNumber.
 		doc := loadXmp(t, "testdata/xmp/synthetic/aux-only.xmp")
 		assert.Equal(t, "BODY-SN-123456", doc.CameraSerial())
 	})