istore

istore is to fill the space between storage, database, application and image recognition. This component is

• an object storage similar to S3
• an image proxy that caches contents as well as processes pixels
• a name service that provides uniform access to different data sources
• a hierarchical database system that maintains metadata associated with each image data, and provides prefix-key iteration
• a backend storage system to applications as well as various database products

Dependency

At the time of wrting, istore depends on ffmpeg installed on the system with pkg-config. In the latest Ubuntu, there is no official package for ffmpeg anymore, so you should build it. Refer to https://gist.github.com/xdamman/e4f713c8cd1a389a5917

User Guide

Currently there is no special client module. You can interact with istore using curl.

Simple Operation

POST

You can POST or PUT any URL object under a path. metadata parameter can register a json associated with the path key.

$ curl -XPOST $HOST/path/sample/http://video.webmfiles.org/elephants-dream.webm -d metadata='{"name": "my video"}'

PUT overwrites the metadata entirely with the input json, whereas POST method merges the input with the existing json.

GET

After you register an object, you can query it.

$ curl -XGET $HOST/path/sample/http://video.webmfiles.org/elephants-dream.webm

This will return the object at the original URL. istore caches the object.

LIST

If you GET at the directory, istore returns the list of json under the directory.

$ curl -XGET $HOST/path/sample/

[{"_id":493,"_filepath":"/path/sample/http://video.webmfiles.org/elephants-dream.webm","metadata":{"name":"my video"}}]

Image Processing

istore implements most of the image processing from the imaging package. To call each function, simply add ?apply={function}&{param}={value}... to GET request.

• adjustBrightness(percentage)
• adjustContrast(percentage)
• adjustGamma(gamma)
• adjustSigmoid(midpoint, factor)
• blur(sigma)
• crop(x1, y1, x2, y2)
• drawRect(rects=[(x1, y1, x2, y2, r, g, b)...])
• fit(w, h)
• flipH()
• flipV()
• grayscale()
• invert()
• sharpen(sigmoid)
• transpose()
• transverse()
• resize(w, h)

For video objects, the below function is available.

• frame(sec)

See also https://godoc.org/github.com/disintegration/imaging

Video Slicing

You can slice video into frames by

$ curl -XPOST $HOST/path/slice/_expand -d '{"video": "/path/to/video"}'

It registers as many objects as duration of the video.

URL Scheme

Currently the following URL schemes is handled.

• http, https Retrieves object from remote http(s)
• file Retrieves object from the local disk of istore
• self Retrieves object from the istore path. This makes it possible to nested image processing.