brstm.js

BRSTM decoder.

Part of Nikku.

Usage example

import { Brstm } from 'brstm';

// BRSTM file should be read and passed as ArrayBuffer type
const brstm = new Brstm(arrayBuffer);

// Here you get an Object containing all the metadata extracted from BRSTM's file HEAD chunk
const metadata = brstm.metadata;

// You get per-channel PCM samples
const samples = brstm.getAllSamples();

// If you don't want the full samples, you can decode them partially
// getSamples(offset, size) will return the per-channel `offset`-th sample until `(offset + size - 1)`-th sample
const samplesPartial = brstm.getSamples(0, 100);

Members

• rawData: {Uint8Array}, representation of array buffer passed in at class constructor.
• metadata: {Object}, the metadata extracted from BRSTM's file HEAD chunk
  • fileSize: {number}
  • endianness: {number}, 0 - little endian, 1 - big endian
  • codec: {number}
    • 0 - 8-bit PCM
    • 1 - 16-bit PCM
    • 2 - 4-bit ADPCM
  • loopFlag: {number}
  • numberChannels: {number}, channel count of the whole file
  • sampleRate: {number}
  • loopStartSample: {number}, loop start, in terms of sample #
  • totalSamples: {number}
  • totalBlocks: {number}, total number of blocks, per channel, including final block
  • blockSize: {number}
  • samplesPerBlock: {number}
  • finalBlockSize: {number}, Final block size, without padding, in bytes
  • finalBlockSizeWithPadding: {number}, Final block size, with padding, in bytes
  • totalSamplesInFinalBlock: {number}, Total samples in final block
  • adpcTableSamplesPerEntry: {number}, Samples per entry in ADPC table
  • adpcTableBytesPerEntry: {number}, Bytes per entry in ADPC table
  • numberTracks: {number}, Number of tracks
  • trackDescriptionType: {number}, Track description type (0 or 1)
  • trackDescriptions: {Array<TrackDescription>}, Basic description of each track
    • TrackDescription: {Object},
      • numberChannels: {number}, this particular track's channel count
      • type: {number}, this particular track's description type (0 or 1)

Methods

• getAllSamples(): {Array<Int16Array>}, per-channel PCM samples
• getSamples(offset, size): {Array<Int16Array>}, per-channel samples from offset-th sample until (offset + size - 1)-th sample