The META
function in SQL provides a way to retrieve metadata information from multimedia data types, such as IMAGE
, AUDIO
, and VIDEO
.
Function Syntax
The META
function uses the following syntax:
META(col[, dirName[, tagName]])
Each parameter serves a distinct purpose:
-
col
: This mandatory parameter specifies the column containing the multimedia data from which you want to retrieve metadata. The column must be of a multimedia data type (IMAGE
,SOUND
, orVIDEO
). -
dirName
: This optional parameter narrows down the scope of the metadata retrieval to a specific directory within the multimedia file. IfdirName
is specified, theMETA
function will only return tags that belong to this directory. -
tagName
: This optional parameter further refines the metadata retrieval by specifying a particular tag. IftagName
is provided, theMETA
function will only return the value of this specific tag.
The metadata information returned by the META
function comprises metadata tags, which are grouped within directories.
Examples
Here are some examples of how the META
function might be used in practice:
To retrieve all metadata from a multimedia column:
SELECT META(ImageColumn) FROM MultimediaTable;
To retrieve all metadata tags from a specific directory:
SELECT META(ImageColumn, 'Directory') FROM MultimediaTable;
To retrieve a specific metadata tag:
SELECT META(ImageColumn, 'Directory', 'Tag') FROM MultimediaTable;
Use Cases
The META
function is particularly useful in various scenarios where it’s necessary to understand more about the characteristics of multimedia data. This may include:
- Image Analysis: Extracting metadata like resolution, color depth, or creation date from image files.
- Sound Processing: Retrieving information like sample rate, bit depth, or duration from sound files.
- Video Processing: Understanding attributes like resolution, frame rate, or encoding format from video files.
Directories and Tags
The following table gives an overview on the directories and tags.
Directory | Tag |
---|---|
Casio Makernote | Print Image Matching (PIM) Info Casio Preview Thumbnail Record Mode Self Timer Thumbnail Dimensions Quality Thumbnail Size Focus Mode Thumbnail Offset Time Zone BestShot Mode Quality Mode Image Size Focus Mode White Balance Bias White Balance ISO Sensitivity CCD ISO Sensitivity Colour Mode Enhancement Filter White Balance Focal Length Saturation Contrast Sharpness Object Distance Flash Distance |
EPS | DSC Version Author Bounding Box Copyright Creation Date Creator For Image Data Keywords Modify Date Pages Routing Subject Title Version Document Data Emulation Extensions Language Level Orientation Page Order Operator Intervention Operator Message Proof Mode Requirements VM Location VM Usage Image Width Image Height Color Type Ram Size TIFF Preview Size TIFF Preview Offset WMF Preview Size WMF Preview Offset Line Continuation |
GIF Control | Delay Disposal Method User Input Flag Transparent Color Flag Transparent Color Index |
MP4 Text | Creation Time Modification Time Duration ISO 639-2 Language Code |
WebP | Image Height Image Width Has Alpha Is Animation |
Sony Makernote | Print Image Matching (PIM) Info Multi Burst Mode Shot Info File Format Multi Burst Image Width Preview Image Sony Model ID Image Quality Multi Burst Image Height Rating Panorama Flash Exposure Compensation Contrast Teleconverter Model Saturation Sharpness Brightness Long Exposure Noise Reduction High ISO Noise Reduction HDR Multi Frame Noise Reduction Picture Effect Soft Skin Effect Camera Info Vignetting Correction White Balance Fine Tune Value Lateral Chromatic Aberration Distortion Correction Camera Settings WB Shift Amber/Magenta White Balance Extra Info Auto Portrait Framing Focus Mode AF Point Selected Focus Info Color Mode Setting Color Temperature Color Compensation Filter Scene Mode Zone Matching Dynamic Range Optimizer Image Stabilisation Lens ID Minolta Makernote Color Mode Lens Spec Full Image Size Preview Image Size Macro Exposure Mode Focus Mode AF Mode AF Illuminator Quality Flash Level Release Mode Sequence Number Anti Blur Long Exposure Noise Reduction Dynamic Range Optimizer High ISO Noise Reduction Intelligent Auto White Balance 2 No Print |
Panasonic Makernote | Print Image Matching (PIM) Info Makernote Version Quality Mode Scene Mode Version White Balance White Balance (Red) White Balance (Green) White Balance (Blue) Focus Mode Flash Fired Text Stamp 2 Text Stamp 3 AF Area Mode Baby Age 1 Transform 1 Image Stabilization Macro Mode Record Mode Audio Unknown Data Dump Easy Mode White Balance Bias Flash Bias Internal Serial Number Exif Version Color Effect Camera Uptime Burst Mode Sequence Number Contrast Mode Noise Reduction Self Timer Rotation AF Assist Lamp Color Mode Baby Age Optical Zoom Mode Conversion Lens Travel Day Contrast World Time Location Text Stamp Program ISO Advanced Scene Mode Text Stamp 1 Number of Detected Faces Saturation Sharpness Film Mode Color Temp Kelvin Bracket Settings White Balance Adjust (AB) White Balance Adjust (GM) Flash Curtain Long Exposure Noise Reduction Panasonic Image Width Panasonic Image Height Af Point Position Face Detection Info Lens Type Lens Serial Number Accessory Type Accessory Serial Number Transform Intelligent Exposure Lens Firmware Version Face Recognition Info Flash Warning Recognized Face Flags Title Baby Name Location Country State City Landmark Intelligent Resolution Burst Speed Intelligent D-Range Clear Retouch City 2 Photo Style Shading Compensation Accelerometer Z Accelerometer X Accelerometer Y Camera Orientation Roll Angle Pitch Angle Sweep Panorama Direction Sweep Panorama Field Of View Timer Recording Internal ND Filter HDR Shutter Type Clear Retouch Value Touch AE |
IPTC | Enveloped Record Version Application Record Version Image Type Object Type Reference Image Orientation Object Attribute Reference Destination Object Name Edit Status Language Identifier Editorial Update Urgency Subject Reference Category File Format Supplemental Category(s) File Version Fixture Identifier Audio Type Audio Sampling Rate Audio Sampling Resolution Keywords Audio Duration Content Location Code Audio Outcue Content Location Name Service Identifier Release Date Release Time Expiration Date Expiration Time Envelope Number Special Instructions Action Advised Reference Service Reference Date Product Identifier Reference Number Date Created Job Identifier Master Document Identifier Short Document Identifier Unique Document Identifier Envelope Priority Time Created Owner Identifier Digital Date Created Digital Time Created Originating Program Date Sent Program Version Object Data Preview File Format Object Data Preview File Format Version Object Data Preview Data Object Cycle Time Sent By-line By-line Title Coded Character Set City Sub-location Province/State Unique Object Name Country/Primary Location Code Country/Primary Location Name Original Transmission Reference Headline Credit Source Copyright Notice Contact ARM Identifier Caption/Abstract Local Caption ARM Version Caption Writer/Editor Rasterized Caption |
Nikon Makernote | Print IM Firmware Version Nikon Capture Data ISO Color Mode Unknown 51 Quality & File Format White Balance Unknown 52 Sharpening AF Type Flash Sync Mode Unknown 53 Auto Flash Mode Nikon Capture Version White Balance Fine White Balance RB Coefficients Program Shift Exposure Difference Nikon Capture Offsets ISO Mode Data Dump Nikon Scan Preview IFD Auto Flash Compensation ISO Image Boundary Flash Exposure Compensation Flash Bracket Compensation AE Bracket Compensation Unknown 54 Flash Mode Crop High Speed Exposure Tuning Camera Serial Number Color Space VR Info Image Authentication Unknown 35 Active D-Lighting NEF Bit Depth Picture Control Unknown 55 World Time ISO Info Unknown 36 Unknown 37 Unknown 38 Unknown 39 Vignette Control Unknown 40 Unknown 41 Unknown 42 Unknown 43 Unknown 44 Unknown 45 Unknown 46 Image Adjustment Tone Compensation Adapter Lens Type Lens Manual Focus Distance Digital Zoom Flash Used AF Focus Position Shooting Mode Unknown 20 Lens Stops Contrast Curve Colour Mode Unknown 47 Scene Mode Light source Shot Info Camera Hue Adjustment NEF Compression Saturation Noise Reduction Linearization Table Color Balance Lens Data NEF Thumbnail Size Sensor Pixel Size Unknown 10 Scene Assist Unknown 11 Retouch History Unknown 12 Camera Serial Number Image Data Size Unknown 27 Unknown 28 Image Count Deleted Image Count Exposure Sequence Number Flash Info Image Optimisation Saturation Digital Vari Program Image Stabilisation AF Response Unknown 29 Unknown 30 Multi Exposure High ISO Noise Reduction Unknown 31 Unknown 32 Unknown 33 Unknown 48 Power Up Time AF Info 2 File Info AF Tune Unknown 49 Unknown 50 |
Apple Run Time | Flags Epoch Scale Value |
Kyocera/Contax Makernote | Print Image Matching (PIM) Info Proprietary Thumbnail Format Data |
Exif SubIFD | Image Width JPEG Proc Related Image File Format Exif Version Temperature FlashPix Version File Source Gamma Components Configuration Interoperability Index Image Height Related Image Width Shutter Speed Value Humidity Color Space Scene Type Custom Rendered Compressed Bits Per Pixel Interoperability Version Bits Per Sample Related Image Height Aperture Value Pressure Exif Image Width CFA Pattern Exposure Mode Compression JPEG Restart Interval Date/Time Original Brightness Value Water Depth Exif Image Height White Balance Mode Date/Time Digitized Exposure Bias Value Acceleration Related Sound File Digital Zoom Ratio JPEG Lossless Predictors Max Aperture Value Camera Elevation Angle Focal Length 35 Photometric Interpretation JPEG Point Transforms Subject Distance Scene Capture Type Thresholding JPEGQ Tables Metering Mode Gain Control JPEGDC Tables White Balance Contrast JPEGAC Tables Flash Saturation Fill Order Focal Length Sharpness Flash Energy Flash Energy Device Setting Description Spatial Frequency Response Spatial Frequency Response Subject Distance Range Document Name Noise Image Description Focal Plane X Resolution Focal Plane X Resolution Make Focal Plane Y Resolution Focal Plane Y Resolution Model Time Zone Focal Plane Resolution Unit Strip Offsets YCbCr Coefficients Time Zone Original Image Number Orientation YCbCr Sub-Sampling Time Zone Digitized Security Classification YCbCr Positioning Image History Reference Black/White Subject Location Subject Location Samples Per Pixel Exposure Index Exposure Index Rows Per Strip TIFF/EP Standard ID Strip Byte Counts Sensing Method Minimum Sample Value Maximum Sample Value X Resolution Y Resolution Planar Configuration Padding Page Name Unique Image ID Exposure Program Spectral Sensitivity ISO Speed Ratings Resolution Unit Opto-electric Conversion Function (OECF) Page Number Interlace Time Zone Offset Self Timer Mode Transfer Function Strip Row Counts Sensitivity Type Camera Owner Name Software Standard Output Sensitivity Body Serial Number Date/Time Recommended Exposure Index Lens Specification ISO Speed Lens Make ISO Speed Latitude yyy Lens Model ISO Speed Latitude zzz Lens Serial Number Artist Host Computer Predictor White Point Primary Chromaticities Tile Width Tile Length Tile Offsets Tile Byte Counts Rating Photoshop Settings Sub IFD Pointer(s) Transfer Range JPEG Tables Inter Color Profile Makernote User Comment CFA Repeat Pattern Dim CFA Pattern Battery Level Sub-Sec Time Sub-Sec Time Original Sub-Sec Time Digitized Copyright Exposure Time Windows XP Title Windows XP Comment F-Number Windows XP Author Windows XP Keywords Windows XP Subject Print Image Matching (PIM) Info IPTC/NAA Application Notes Panasonic Title Panasonic Title (2) Lens New Subfile Type Subfile Type |
Kodak Makernote | Kodak Model White Balance Quality Burst Mode Image Width Image Height Year Created Month/Day Created Time Created Burst Mode 2 Shutter Speed Metering Mode Flash Mode Sequence Number Flash Fired F Number ISO Setting Exposure Time ISO Total Zoom Exposure Compensation Date/Time Stamp Color Mode Digital Zoom Sharpness Focus Mode |
Olympus Makernote | Pre Capture Frames Thumbnail Image Special Mode Makernote Version Print Image Matching (PIM) Info Data Dump Shutter Speed Value Raw Info Main Info Camera Settings Colour Mode JPEG Quality White Board Data Dump 2 ISO Value Image Quality Macro One Touch WB Aperture Value Exposure Mode Camera Settings Image Quality BW Mode White Balance Bracket Scene Mode Brightness Value Flash Mode Body Firmware Version Digital Zoom White Balance Bias Serial Number Flash Mode White Balance Focal Plane Diagonal Firmware Flash Device Image Size Lens Distortion Parameters Bracket Image Quality Camera Type Sensor Temperature Shooting Mode Pict Info Lens Temperature Metering Mode Camera Id Light Condition Apex Film Speed Value Focus Range Apex Shutter Speed Time Value Image Width Focus Mode Apex Aperture Value Image Height Focus Distance Macro Mode Original Manufacturer Model Zoom Digital Zoom Macro Focus Exposure Compensation Sharpness Bracket Step Flash Charge Level Equipment Colour Matrix Interval Length Black Level Interval Number Color Temperature BG Focal Length Color Temperature RG Focus Distance White Balance Mode Flash Fired Date Red Balance Time Blue Balance Max Aperture at Focal Length Color Matrix Number Serial Number External Flash AE1 0 File Number Memory External Flash AE2 0 Last File Number Internal Flash AE1 0 White Balance Red Internal Flash AE2 0 White Balance Green External Flash AE1 White Balance Blue External Flash AE2 Camera Settings Saturation Internal Flash AE1 Contrast Internal Flash AE2 Sharpness Flash Bias Subject Program Internal Flash Table Flash Compensation External Flash G Value ISO Setting External Flash Bounce Camera Model External Flash Zoom Interval Mode External Flash Mode Folder Name Contrast Color Mode Sharpness Factor Color Filter Colour Control Black and White Filter Valid Bits Internal Flash Coring Filter Apex Brightness Value Olympus Image Width Spot Focus Point X Coordinate Olympus Image Height Spot Focus Point Y Coordinate Scene Detect Raw Development Wide Focus Zone Scene Area Raw Development 2 Focus Mode Focus Area Scene Detect Data DEC Switch Position Compression Ratio Preview Image Valid Preview Image Start Preview Image Length AF Result CCD Scan Mode Noise Reduction Infinity Lens Step Near Lens Step Light Value Center Light Value Periphery Field Count Compressed Image Size Image Processing Focus Info Preview Image Thumbnail Offset Thumbnail Offset Thumbnail Length |
PrintIM | PrintIM Version |
PanasonicRaw DistortionInfo | Distortion Param 2 Distortion Param 4 Distortion Scale Distortion Correction Distortion Param 8 Distortion Param 9 Distortion Param 11 Distortion N |
Olympus Equipment | Equipment Version Camera Type 2 Flash Type Serial Number Lens Type Extender Flash Model Internal Serial Number Lens Serial Number Extender Serial Number Flash Firmware Version Focal Plane Diagonal Lens Model Extender Model Conversion Lens Flash Serial Number Body Firmware Version Lens Firmware Version Extender Firmware Version Max Aperture At Min Focal Max Aperture At Max Focal Min Focal Length Max Focal Length Max Aperture Lens Properties |
JPEG | Data Precision Image Height Compression Type Image Width Number of Components Component 1 Component 2 Component 3 Component 4 |
PanasonicRaw WbInfo2 | Num WB Entries WB Type 1 WB RGB Levels 1 WB Type 2 WB RGB Levels 2 WB Type 3 WB RGB Levels 3 WB Type 4 WB RGB Levels 4 WB Type 5 WB RGB Levels 5 WB Type 6 WB RGB Levels 6 WB Type 7 WB RGB Levels 7 |