# Stt-align-node
See [The alignment problem](./docs/the-alignment-problem.md) in the docs for more background of the problem this module set out to address.
Originally developed as a node version of python's [stt-align](https://github.com/bbc/stt-align) by Chris Baume - BBC R&D.
## Setup - development
```
git clone git@github.com:pietrop/stt-align-node.git
```
```
cd stt-align-node
```
```
npm install
```
## Setup - in production
```
npm install stt-align-node
```
---
## Usage
Other then to realign STT results with accurate text, this modules can also be used to perform related oprations in the same domain, such as benchmarking STT.
| Function | Description | type |
| :--------------------------- | ------------------------------------------------------------------------------------------------- | -------- |
| `alignSTT` | Realign STT json with accurate text. by transposing words from accurate text to timecodes of STT. | `json` |
| `diffsList` | return a diff json of STT vs accurate text | `json` |
| `diffsListAsHtml` | return a diff of STT vs accurate text as HTML | `html` |
| `diffsListAsHtmlContentOnly` | return a diff of STT vs accurate text as HTML content | `html` |
| `diffsCount` | return a diff of STT vs accurate text as HTML | `json` |
| `calculateWordDuration` | return a diff of STT vs accurate text as HTML | `Number` |
See [See `README` in `example-usage` folder](./example-usage/README.md) as well as [code examples](./example-usage) for more.
alignSTT
```js
const { alignSTT } = require('stt-align-node');
const result = alignSTT(transcriptStt, transcriptText);
// Do something with the result
```
diffsList
```js
const { diffsList } = require('stt-align-node');
const result = diffsList(trainscriptSttText, transcriptText);
// Do something with the result
```
diffsListAsHtml
```js
const { diffsListAsHtml } = require('stt-align-node');
const result = diffsListAsHtml(trainscriptSttText, transcriptText, url);
// // Do something with the result
```
diffsListAsHtmlContentOnly
```js
const { diffsListAsHtmlContentOnly } = require('stt-align-node');
const result = diffsListAsHtmlContentOnly(trainscriptSttText, transcriptText);
// // Do something with the result
```
diffsCount
```js
const { diffsCount } = require('stt-align-node');
const result = diffsCount(trainscriptSttText, transcriptText);
```
example output
```json
{ "equal": 1415, "insert": 8, "replace": 307, "delete": 62, "baseTextTotalWordCount": 1784, "wer": 0.21132286995515695 }
```
## System Architecture
Node version of stt-align by Chris Baume - R&D.
In _pseudo code_ overview of `alignSTT`:
- input, output as described in the example usage.
- Accurate base text transcription, string.
- Array of word objects transcription from STT service.
- Align words
- normalize words, by removing capitalization and punctuation and converting numbers to letters
- generate array list of words from base text, and array list of words from stt transcript.
- get [opcodes](https://docs.python.org/2/library/difflib.html#difflib.SequenceMatcher.get_opcodes) using `difflib` comparing two arrays
- for equal matches, add matched STT word objects segment to results array base text index position.
- Then iterate to result array to replace STT word objects text with words from base text
- interpolate missing words
- calculates missing timecodes
- first optimization
- using neighboring words to do a first pass at setting missing start and end time when present
- Then Missing word timings are interpolated using interpolation library [`'everpolate`](http://borischumichev.github.io/everpolate/#linear).
## Development env
- node `10`
- npm `6.1.0`
## Build
```
npm run build
```
bundles the code with react, into a `./build` folder.
## build demo
```
npm run build:demo
```
Demo is in docs folder
Publish demo to github pages
```
npm run deploy:ghpages
```
## Tests
```
npm run test:watch
```
- [ ] add more tests
## Deployment
Deploy to npm
```
npm run publish:public
```