BPCM2: Entropy encoded ADPCM audio codec version 2.0.0.0 "Feline"

QuickLinks

• Usage
  • Encoding options
  • Player options
• Tewaks
• Stream Stucture
• Stream VERSION 2

Usage

• Encode: bpcm input.wav output.bpcm
• Decode: bpcm input.bpcm output.wav
• Playback: bpcm input.bpcm

You can place your option parameters anywhere you like!

Encoding options

1. -c string Use specific compression method
   • ► none
   • ► ac (Arithmetic order0)
   • ► BZIP2
   • ► LZMA
   • ► fast (use best result of LZMA and ac [DEFAULT] [RECOMMENDED!]),
   • ► brute (use best result of all)
2. -bs number Sets the block size in milliseconds, default is 100 ms

Player options

• -vol decimal Sets the initial playback volume from 0 ... 1 (float). Default is 0.12.
• -r decimal Sets the initial playback speed as a factor value (float). Default is 1.
• -od number Audio output device (0 = system default) ► 0: Lautsprecher (USB Sound Blaster ► 1: Headphones (Realtek High Defini ► 2: SPDIF-Out (USB Sound Blaster HD

Tewaks

= Encoding =

• -sltrh number Sets the silence threshold from 0 ... 32747 (integer). Default is 4 = Decoding / Playback =
• -nodither Disables random dithering on decoding, makes decoding faster

Stream structure

Stream VERSION 2

This version range supports only 16 bit sampling input in INTEL little endian (in VLC called s16l)!

• SYNC BYTE

0xB1 //Implies Version 2

• FRAME STRUCTURE Two zeros = one byte, so 00 | 00 = word (16 bit) and 00 | 00 | 00 24 bit word so 3 bytes:

SYNC | INFO | nSamples *1  | DATA-LEN     | DATA*2 ----------------------->
B1   | 00   | 00 | 00      | 00 | ?? | ?? | [BINARY COMPRESSED AUDIO DATA]

*1 only when we need to set a block size
*2: only when data available, the datatype varies between 1 and 3 bytes
   On a silent frame it contains a double value after the info byte!
   (BZIP2 = 8, LZMA = 16 and arithmetic = 24 bit) with the sample count.
   In case compression is none, this frame is rejected!

• INFO BYTE

  • BIT 12 = data available? (see table)
  • BIT 34 = compression type (see table)
  • BIT 5 = channel config: 0=mono, 1=stereo
  • BIT 6 = use last blocksize: 0=use given (*1 is written) 1=use last
  • BIT 78 = sampling clock (see table)

• Data address table

  • 00 0 = No data / silence
  • 01 1 = 8 bit data length addressing
  • 10 2 = 16 bit data length addressing
  • 11 3 = 24 bit data length addressing

• Compression type table

  • 00 0 = none
  • 01 1 = BZIP2
  • 10 2 = LZMA
  • 11 3 = arithmetic order0

• Sampling clock table:

  • 00 0 = 44100 Hz
  • 01 1 = 48000 Hz
  • 10 2 = 32000 Hz
  • 11 3 = 24000 Hz