Silk SDK

This is node-gyp version of Silk SDK library (see https://developer.skype.com/silk for details.)

Installation

To install this package, please run:

npm install silk-sdk

or

yarn add silk-sdk

If you wish to use cli tool, try install globally using:

npm install silk-sdk --global

or

yarn global add silk-sdk

Command Usage

decode

To decode silk format audio, run:

silk-sdk decode [input] [output]

where input is the name of input file and output is the name of output file. You can pass further options after, availables are shown below:

• -q, --quiet Whether there is any output into console (default: false)
• --lossProb [lossProb] Simulated packet loss percentage (0-100) (default: 0)
• --fsHz [fs] Sampling rate of output signal in Hz (default: 24000)

encode

To encode audio to silk format, run:

silk-sdk encode [input] [output]

where input is the name of input file and output is the name of output file. You can pass further options after, availables are shown below:

• -q, --quiet Whether there is any output into console (default: false)
• --fsHz [fs] API sampling rate in Hz (default: 24000)
• --fxMaxInternal [fxMaxInternal] Maximum internal sampling rate in Hz (default: 0)
• --packetLength [packageLength] Packet interval in ms (default: 20)
• --rate Target bitrate (default: 25000)
• --loss Uplink loss estimate, in percent (0-100) (default: 0)
• --complexity Set complexity, 0: low, 1: medium, 2: high (default: 2)
• --inbandFEC Enable inband FEC usage (default: false)
• --dtx Enable DTX (default: false)
• --tencent Add Tencent (Wechat, QQ) header in exported file (default: false)
• --tencentAmr Add Tencent AMR header in exported file (default: false)

compare

To compare to silk format audio files, run:

silk-sdk compare [ref] [test]

where ref is the name of first file and test is the name of second file. You can pass further options after, availables are shown below:

• -q, --quiet Whether there is any output into console (default: false)
• --diff Only determine bit-exactness (default: false)
• --fs Sampling rate in Hz, max is 48000 (default: 24000)

API Usage

decode

This API will decode silk format audio. It's return value and behavior will change depends on the parameters provided.

Stream.Transform decode(options)

| Parameter | Type | Required | Description | | --------- | ------ | -------- | --------------------------------------- | | options | object | false | Optional options, see below for details |

This API will return a transform stream, which can be used to consume input stream and generate decode stream.

Exmaple usage:

fs.createReadStream('input-path-here')
  .pipe(silk.decode({ quiet: true }))
  .pipe(fs.createWriteStream('output-path-here'));

buffer decode(input, options)

| Parameter | Type | Required | Description | | --------- | ------------- | -------- | --------------------------------------- | | input | string/buffer | true | Bitstream input to decoder | | options | object | false | Optional options, see below for details |

For first parameter input, you can pass in either string or buffer. If string is provided, it will be used as path of file; if buffer is provided, it should be the buffer of input file.

This API will return a decoded buffer that can be either saved in file or used by other APIs.

Example usage:

fs.writeFileSync(silk.decode('input-path-here', { quiet: true }));

void decode(input, output, options)

| Parameter | Type | Required | Description | | --------- | ------------- | -------- | --------------------------------------- | | input | string/buffer | true | Bitstream input to decoder | | output | string | true | Speech output (file path) from decoder | | options | object | false | Optional options, see below for details |

For first parameter input, you can pass in either string or buffer. If string is provided, it will be used as path of file; if buffer is provided, it should be the buffer of input file.

No return for this API, decode result will be saved to output path directly.

Example usage:

silk.decode('./input.silk', './output.pcm', { quiet: true });

Options

| Attribute | Type | Default | Description | | --------- | ------- | --------| ---------------------------------------- | | quiet | boolean | true | Whether there is any output into console | | lossProb | float | 0 | Simulated packet loss percentage (0-100) | | fsHz | int | 24000 | Sampling rate of output signal in Hz |

encode

This API will encode speech input to silk format. It's return value and behavior will change depends on the parameters provided.

Stream.Transform encode(options)

| Parameter | Type | Required | Description | | --------- | ------ | -------- | --------------------------------------- | | options | object | false | Optional options, see below for details |

This API will return a transform stream, which can be used to consume input stream and generate decode stream.

Exmaple usage:

fs.createReadStream('input-path-here')
  .pipe(silk.encode({ quiet: true }))
  .pipe(fs.createWriteStream('output-path-here'));

buffer encode(input, options)

| Parameter | Type | Required | Description | | --------- | ------------- | -------- | --------------------------------------- | | input | string/buffer | true | Speech input to encoder | | options | object | false | Optional options, see below for details |

For first parameter input, you can pass in either string or buffer. If string is provided, it will be used as path of file; if buffer is provided, it should be the buffer of input file.

This API will return a encoded buffer that can be either saved in file or used by other APIs.

Example usage:

fs.writeFileSync(silk.encode('input-path-here', { quiet: true }));

void decode(input, output, options)

| Parameter | Type | Required | Description | | --------- | ------------- | -------- | --------------------------------------- | | input | string/buffer | true | Speech input to encoder | | output | string | true | Bitstream output from encoder | | options | object | false | Optional options, see below for details |

For first parameter input, you can pass in either string or buffer. If string is provided, it will be used as path of file; if buffer is provided, it should be the buffer of input file.

No return for this API, encode result will be saved to output path directly.

Example usage:

silk.encode('./input.silk', './output.pcm', { quiet: true });

Options

| Attribute | Type | Default | Description | | ------------- | ------- | --------| ------------------------------------------------ | | quiet | boolean | true | Whether there is any output into console | | fsHz | int | 24000 | API sampling rate in Hz | | fxMaxInternal | int | 0 | Maximum internal sampling rate in Hz | | packetLength | int | 20 | Packet interval in ms | | rate | int | 25000 | Target bitrate | | loss | int | 0 | Uplink loss estimate, in percent (0-100) | | complexity | int | 2 | Set complexity, 0: low, 1: medium, 2: high | | inbandFEC | boolean | false | Enable inband FEC usage | | dtx | boolean | false | Enable DTX | | tencent | boolean | false | Add Tencent (Wechat, QQ) header in exported file | | tencentAmr | boolean | false | Add Tencent AMR header in exported file |

compare

bool compare(input, output, stream)

Compare two audio files.

| Parameter | Type | Required | Description | | --------- | ------------- | -------- | ----------------------------------------------------------- | | inputA | string/buffer | true | Reference file | | inputB | string/buffer | true | File to be tested, should be of same length as inputA (pcm) | | options | object | false | Optional options, see below for details |

For both inputA and inputB, you can pass in either string or buffer. If string is provided, it will be used as path of file; if buffer is provided, it should be the buffer of input file.

Below are possible options for compare.

| Attribute | Type | Default | Description | | ------------- | ------- | --------| ---------------------------------------- | | quiet | boolean | true | Whether there is any output into console | | diff | boolean | false | Only determine bit-exactness | | fs | int | 24000 | Sampling rate in Hz, max is 48000 |

Example usage:

const silk = require('silk-sdk');
silk.compare('./ref.pcm', './test.pcm', { quiet: true });

License

This wrap of original Silk SDK code is under MIT License. For Silk SDK itself, please check their license for details.