class WaveFile::Format

Represents information about the data format for a Wave file, such as number of channels, bits per sample, sample rate, and so forth. A Format instance is used by Reader to indicate what format to read samples out as, and by Writer to indicate what format to write samples as.

This class is immutable - once a new Format is constructed, it can't be modified.

Public

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Attributes

bits_per_sample[R]

Returns

Returns the number of bits per sample, such as 8, 16, 24, 32, or 64.

block_align[R]

Returns

Returns the number of bytes in each sample frame. For example, in a 16-bit stereo file, this will be 4 (2 bytes for each 16-bit sample, times 2 channels).

byte_rate[R]

Returns

Returns the number of bytes contained in 1 second of sample data. Is equivalent to #block_align * sample_rate.

channels[R]

Returns

Returns the number of channels, such as 1 or 2. This will always return a Integer, even if the number of channels is specified with a symbol (e.g. :mono) in the constructor.

sample_format[R]

Returns

Returns a symbol indicating the sample format, such as :pcm or :float

sample_rate[R]

Returns

Returns the number of samples per second, such as 44100.

Public Class Methods

new(channels, format_code, sample_rate) click to toggle source

Constructs a new immutable Format.

channels

The number of channels in the format. Can either be an Integer (e.g. 1, 2, 3) or the symbols :mono (equivalent to 1) or :stereo (equivalent to 2).

format_code

A symbol indicating the format of each sample. Consists of two parts: a format code, and the bits per sample. The valid values are :pcm_8, :pcm_16, :pcm_24, :pcm_32, :float_32, :float_64, and :float (equivalent to :float_32)

#sample_rate

The number of samples per second, such as 44100

Examples

format = Format.new(1, :pcm_16, 44100)
format = Format.new(:mono, :pcm_16, 44100)  # Equivalent to above

format = Format.new(:stereo, :float_32, 44100)
format = Format.new(:stereo, :float, 44100)  # Equivalent to above
# File lib/wavefile/format.rb, line 41
def initialize(channels, format_code, sample_rate)
  channels = normalize_channels(channels)
  sample_format, bits_per_sample = normalize_format_code(format_code)
  validate_channels(channels)
  validate_sample_format(sample_format)
  validate_bits_per_sample(sample_format, bits_per_sample)
  validate_sample_rate(sample_rate)

  @channels = channels
  @sample_format = sample_format
  @bits_per_sample = bits_per_sample
  @sample_rate = sample_rate
  @block_align = (@bits_per_sample / 8) * @channels
  @byte_rate = @block_align * @sample_rate
end

Public Instance Methods

mono?() click to toggle source

Returns

Returns true if the format has 1 channel, false otherwise.

# File lib/wavefile/format.rb, line 58
def mono?
  @channels == 1
end
stereo?() click to toggle source

Returns

Returns true if the format has 2 channels, false otherwise.

# File lib/wavefile/format.rb, line 63
def stereo?
  @channels == 2
end