lib/scissor/sound_file.rb in scissor-0.4.0 vs lib/scissor/sound_file.rb in scissor-0.5.0

@@ -1,6 +1,7 @@
 require 'mp3info'
+require 'mp4info'
 require 'pathname'
 require 'riff/reader'
 
 module Scissor
   class SoundFile
@@ -42,13 +43,31 @@
       def fmt
         @fmt ||= riff.root_chunk['fmt ']
       end
     end
 
+    class M4a < SoundFile
+      def length
+        info.SECS_NOROUND
+      end
+
+      # FIXME
+      def mono?
+        false
+      end
+
+      private
+
+      def info
+        @info ||= MP4Info.open(@filename.to_s)
+      end
+    end
+
     SUPPORTED_FORMATS = {
       :mp3 => Mp3,
-      :wav => Wav
+      :wav => Wav,
+      :m4a => M4a
     }
 
     class Error < StandardError; end
     class UnknownFormat < Error; end
 
@@ -63,7 +82,40 @@
     end
 
     def initialize(filename)
       @filename = Pathname.new(filename)
     end
+  end
+end
+
+class MP4Info
+  private
+
+  def parse_mvhd(io_stream, level, size)
+    raise "Parse error" if size < 32
+    data = read_or_raise(io_stream, size, "Premature end of file")
+
+    version = data.unpack("C")[0] & 255
+    if (version == 0)
+      scale, duration = data[12..19].unpack("NN")
+    elsif (version == 1)
+      scale, hi, low = data[20..31].unpack("NNN")
+      duration = hi * (2**32) + low
+    else
+      return
+    end
+
+    printf " %sDur/Scl=#{duration}/#{scale}\n", ' ' * ( 2 * level ) if $DEBUG
+
+    secs = (duration * 1.0) / scale
+
+    # add
+    @info_atoms["SECS_NOROUND"] = secs
+
+    @info_atoms["SECS"] = (secs).round
+    @info_atoms["MM"] = (secs / 60).floor
+    @info_atoms["SS"] = (secs - @info_atoms["MM"] * 60).floor
+    @info_atoms["MS"] = (1000 * (secs - secs.floor)).round
+    @info_atoms["TIME"] = sprintf "%02d:%02d", @info_atoms["MM"],
+    @info_atoms["SECS"] - @info_atoms["MM"] * 60;
   end
 end