Class: DTAS::Format

Inherits:
Object
  • Object
show all
Includes:
Process, Serialize
Defined in:
lib/dtas/format.rb

Overview

:nodoc:

Constant Summary collapse

NATIVE_ENDIAN = 
[1].pack("l") == [1].pack("l>") ? "big" : "little"
FORMAT_DEFAULTS = 
{
  "type" => "s32",
  "channels" => 2,
  "rate" => 44100,
  "bits" => nil,   # default: implied from type
  "endian" => nil, # unspecified
}
SIVS =

unspecified

FORMAT_DEFAULTS.keys

Constants included from Process

Process::PIDS

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Serialize

#ivars_to_hash

Methods included from Process

#dtas_spawn, #qx, reaper, #xs

Constructor Details

#initialize ⇒ Format

Returns a new instance of Format.



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# File 'lib/dtas/format.rb', line 38

def initialize
  FORMAT_DEFAULTS.each do |k,v|
    instance_variable_set("@#{k}", v)
  end
end

Instance Attribute Details

#bits ⇒ Object

only set for playback on 16-bit DACs



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# File 'lib/dtas/format.rb', line 17

def bits
  @bits
end

#channels ⇒ Object

1..666



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# File 'lib/dtas/format.rb', line 15

def channels
  @channels
end

#endian ⇒ Object

Returns the value of attribute endian.



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# File 'lib/dtas/format.rb', line 18

def endian
  @endian
end

#rate ⇒ Object

44100, 48000, 88200, 96000, 176400, 192000 …



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# File 'lib/dtas/format.rb', line 16

def rate
  @rate
end

#type ⇒ Object

s32, f32, f64 … any point in others?



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# File 'lib/dtas/format.rb', line 14

def type
  @type
end

Class Method Details

.load(hash) ⇒ Object 



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# File 'lib/dtas/format.rb', line 29

def self.load(hash)
  fmt = new
  return fmt unless hash
  (SIVS & hash.keys).each do |k|
    fmt.instance_variable_set("@#{k}", hash[k])
  end
  fmt
end

Instance Method Details

#bits_per_sample ⇒ Object

for the decoded output



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# File 'lib/dtas/format.rb', line 86

def bits_per_sample
  return @bits if @bits
  /\A[fst](8|16|24|32|64)\z/ =~ @type or
    raise TypeError, "invalid type=#@type (must be s32/f32/f64)"
  $1.to_i
end

#bytes_per_sample ⇒ Object 



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# File 'lib/dtas/format.rb', line 93

def bytes_per_sample
  bits_per_sample / 8
end

#bytes_to_samples(bytes) ⇒ Object 



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# File 'lib/dtas/format.rb', line 114

def bytes_to_samples(bytes)
  bytes / bytes_per_sample / @channels
end

#bytes_to_time(bytes) ⇒ Object 



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# File 'lib/dtas/format.rb', line 118

def bytes_to_time(bytes)
  Time.at(bytes_to_samples(bytes) / @rate.to_f)
end

#endian2 ⇒ Object

returns ‘be’ or ‘le’ depending on endianess



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# File 'lib/dtas/format.rb', line 51

def endian2
  case e = @endian || NATIVE_ENDIAN
  when "big"
    "be"
  when "little"
    "le"
  else
    raise"unsupported endian=#{e}"
  end
end

#from_file(path) ⇒ Object 



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# File 'lib/dtas/format.rb', line 78

def from_file(path)
  @channels = qx(%W(soxi -c #{path})).to_i
  @type = qx(%W(soxi -t #{path})).strip
  @rate = qx(%W(soxi -r #{path})).to_i
  # we don't need to care for bits, do we?
end

#hhmmss_to_samples(hhmmss) ⇒ Object

HH:MM:SS.frac (don’t bother with more complex times, too much code) part of me wants to drop this feature from playq, feels like bloat…

Raises:

  • (ArgumentError) 


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# File 'lib/dtas/format.rb', line 132

def hhmmss_to_samples(hhmmss)
  time = hhmmss.dup
  rv = 0
  if time.sub!(/\.(\d+)\z/, "")
    # convert fractional second to sample count:
    rv = ("0.#$1".to_f * @rate).to_i
  end

  # deal with HH:MM:SS
  t = time.split(/:/)
  raise ArgumentError, "Bad time format: #{hhmmss}" if t.size > 3

  mult = 1
  while part = t.pop
    rv += part.to_i * mult * @rate
    mult *= 60
  end
  rv
end

#inspect ⇒ Object 



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# File 'lib/dtas/format.rb', line 66

def inspect
  "<#{self.class}(#{xs(to_sox_arg)})>"
end

#to_eca_arg ⇒ Object 



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# File 'lib/dtas/format.rb', line 62

def to_eca_arg
  %W(-f #{@type}_#{endian2},#@channels,#@rate)
end

#to_env ⇒ Object 



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# File 'lib/dtas/format.rb', line 97

def to_env
  rv = {
    "SOX_FILETYPE" => @type,
    "CHANNELS" => @channels.to_s,
    "RATE" => @rate.to_s,
    "ENDIAN" => @endian || NATIVE_ENDIAN,
    "SOXFMT" => to_sox_arg.join(' '),
    "ECAFMT" => to_eca_arg.join(' '),
    "ENDIAN2" => endian2,
  }
  begin # don't set these if we can't get them, SOX_FILETYPE may be enough
    rv["BITS_PER_SAMPLE"] = bits_per_sample.to_s
  rescue TypeError
  end
  rv
end

#to_hash ⇒ Object 



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# File 'lib/dtas/format.rb', line 74

def to_hash
  ivars_to_hash(SIVS)
end

#to_hsh ⇒ Object 



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# File 'lib/dtas/format.rb', line 70

def to_hsh
  to_hash.delete_if { |k,v| v == FORMAT_DEFAULTS[k] }
end

#to_sox_arg ⇒ Object 



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# File 'lib/dtas/format.rb', line 44

def to_sox_arg
 rv = %W(-t#@type -c#@channels -r#@rate)
 rv.concat(%W(-b#@bits)) if @bits # needed for play(1) to 16-bit DACs
 rv
end

#valid_endian?(endian) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/dtas/format.rb', line 126

def valid_endian?(endian)
  !!(endian =~ %r{\A(?:big|little|swap)\z})
end

#valid_type?(type) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/dtas/format.rb', line 122

def valid_type?(type)
  !!(type =~ %r{\A[us](?:8|16|24|32)\z} || type =~ %r{\Af?:(32|64)})
end