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Contents
module FLV
# The body of a video tag.
# The data is quite complex stuff. We make no attempt to understand it all
# or to be able to modify any of it. We simply consider it a complex string
# and read the interesting bits to give more info.
class Video < String
include Body
CODECS = Hash.new(:unknown).merge!(
1 => :JPEG,
2 => :h263,
3 => :screen,
4 => :on2_vp6,
5 => :on2_vp6_alpha,
6 => :screen_v2,
7 => :AVC
).freeze
FRAMES = Hash.new(:unknown).merge!(
1 => :keyframe ,
2 => :interframe,
3 => :disposable_interframe
).freeze
def frame_type
FRAMES[read_bits(0...4)]
end
def codec_id
read_bits(4...8)
end
def codec
CODECS[codec_id]
end
# Dimensions for h263 encoding; either as a bit range or the final value
H263_DIMENSIONS = {
0 => [41...49, 49...57],
1 => [41...57, 57...73],
2 => [352, 288],
3 => [176, 144],
4 => [128, 96] ,
5 => [320, 240],
6 => [160, 120]
}.freeze
# Returns dimensions as {:width => w, :height => h}, for Sorensen H.263 and screen video codecs only (otherwise returns nil)
def dimensions
w, h = case codec
when :h263
H263_DIMENSIONS[read_bits(38...41)]
when :screen
[12...24, 24...32]
end
return nil unless w
w, h = [w, h].map{ |r| read_bits(r) } if w.is_a?(Range)
{:width => w, :height => h}
end
def is?(what)
frame_type.to_s.downcase == what.to_s.downcase || super
end
def getters
super - [:frame_type, :frame_type.to_s] # Let's exclude the frame_type from the normal attributes... (string vs symbol: ruby 1.8 vs 1.9)
end
def title
super + " (#{frame_type})" # ...and include it in the title instead.
end
end
end
Version data entries
16 entries across 16 versions & 2 rubygems