Class: FLV::Edit::Processor::MetaDataMaker

Inherits:
Base
  • Object
show all
Includes:
Dispatcher
Defined in:
lib/flvedit/processor/meta_data_maker.rb

Overview

MetaDataMaker is a Processor class (see Base) that computes the metadata for its sources. The metadata for the current source is accessible with #meta_data It is used by Update.

Defined Under Namespace

Classes: Info

Constant Summary collapse

CHUNK_LENGTH_SIZE =

todo: calc instead?

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TAG_HEADER_SIZE =

todo: calc instead?

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TOTAL_EXTRA_SIZE_PER_TAG = 
CHUNK_LENGTH_SIZE + TAG_HEADER_SIZE

Constants included from Dispatcher

Dispatcher::ALL_EVENTS, Dispatcher::EVENT_TRIGGER, Dispatcher::EVENT_TRIGGER_LIST, Dispatcher::MAIN_EVENTS

Instance Attribute Summary

Attributes inherited from Base

#options

Instance Method Summary collapse

Methods included from Dispatcher

#absorb, #dispatch_instead, #each, included, #initialize, #stop

Methods inherited from Base

#clone, #each, #each_source, #initialize, #process_all

Instance Method Details

#meta_data ⇒ Object 



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# File 'lib/flvedit/processor/meta_data_maker.rb', line 57

def meta_data
  frame_sequence_in_ms = @video_interval_stats.index(@video_interval_stats.values.max)
  last_ts = @info.values.map{|h| h.last}.compact.map(&:timestamp).map(&:in_seconds).max
  duration = last_ts + frame_sequence_in_ms/1000.0

  meta = @info[Video].last.body.dimensions if @info[Video].last
  meta ||= {:width => @previous_meta[:width], :height => @previous_meta[:height]} if @previous_meta
  meta ||= {}
  [Video, Audio].each do |k|
    h = @info[k]
    type = k.name.gsub!("FLV::","").downcase

    meta[:"#{type}size"] = h.bytes + h.tag_count * TAG_HEADER_SIZE
    meta[:"#{type}datarate"] = h.bytes / duration * 8 / 1000 #kbits/s
    if meta[:"has#{type.capitalize}"] = h.first != nil
      meta[:"#{type}codecid"] = h.first.codec_id
    end
  end
        
  meta.merge!(
    :filesize               => total_size,
    :datasize               => total_size - @info[Header].bytes - CHUNK_LENGTH_SIZE*(1 + @info.values.sum(&:tag_count)),
    :lasttimestamp          => last_ts,
    :framerate              => frame_sequence_in_ms ? 1000.0/frame_sequence_in_ms : 0,
    :duration               => duration,

    :hasCuePoints           => !@cue_points.empty?,
    :cuePoints              => @cue_points.map(&:body),
    :hasKeyframes           => !@key_frames.empty?,
    :keyframes              => time_positions_to_hash(@key_frames),

    :hasMetadata            => true, #duh! Left for compatibility with FLVTool2, but I can't believe anyone would actually check on this...
    :metadatadate           => Time.now,
    :metadatacreator        => 'flvedit........................................................'
  )

  meta.merge!(
    :audiodelay             => @info[Video].first.timestamp.in_seconds,
    :canSeekToEnd           => @info[Video].last.frame_type == :keyframe,
    :lastkeyframetimestamp  => @key_frames.last.first || 0
  ) if meta[:hasVideo]
  
  meta.merge!(
    :stereo                 => @info[Audio].first.channel == :stereo,
    :audiosamplerate        => @info[Audio].first.rate,
    :audiosamplesize        => @info[Audio].first.sample_size
  ) if meta[:hasAudio]

  # Adjust all sizes for this new meta tag
  meta_size = Tag.new(0, meta).size
  # p "Size of meta: #{meta_size}"
  # p "Info: #{@info.values.map(&:bytes).inspect} #{@info.values.map(&:tag_count).inspect}"
  meta[:filesize] += meta_size
  meta[:datasize] += meta_size
  meta[:keyframes][:filepositions].map! {|ts| ts + meta_size} if meta[:hasKeyframes]
  meta[:cuePoints][:filepositions].map! {|ts| ts + meta_size} if meta[:hasCuePoints]

  meta.merge!(YAML.load_file(options[:update]).symbolize_keys!) if options[:update]

  meta
end

#on_cue_point(t) ⇒ Object 



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# File 'lib/flvedit/processor/meta_data_maker.rb', line 48

def on_cue_point(t)
  @cue_points << t
end

#on_header(header) ⇒ Object 



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# File 'lib/flvedit/processor/meta_data_maker.rb', line 18

def on_header(header)
  @cue_points = []
  @key_frames = []
  @video_interval_stats = Hash.new(0)
  @info = Hash.new{|h, key| h[key] = Info.new(0,0,nil,nil)}
  @info[Header].bytes = header.size
  # Header is not a tag, so leave tag_count at 0
end

#on_keyframe(t) ⇒ Object 



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# File 'lib/flvedit/processor/meta_data_maker.rb', line 44

def on_keyframe(t)
  @key_frames << [t.timestamp.in_seconds, self.total_size]
end

#on_meta_data(t) ⇒ Object 



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# File 'lib/flvedit/processor/meta_data_maker.rb', line 35

def on_meta_data(t)
  @previous_meta = t
  absorb
end

#on_tag(tag) ⇒ Object 



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# File 'lib/flvedit/processor/meta_data_maker.rb', line 27

def on_tag(tag)
  h = @info[tag.body.class]
  h.first ||= tag
  h.last = tag
  h.bytes += tag.body.size
  h.tag_count += 1
end

#on_video(t) ⇒ Object 



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# File 'lib/flvedit/processor/meta_data_maker.rb', line 40

def on_video(t)
  @video_interval_stats[t.timestamp.in_milliseconds - @info[Video].last.timestamp.in_milliseconds] += 1   if @info[Video].last
end

#time_positions_to_hash(time_position_pairs) ⇒ Object 



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# File 'lib/flvedit/processor/meta_data_maker.rb', line 52

def time_positions_to_hash(time_position_pairs)
  times, filepositions = time_position_pairs.transpose
  {:times => times || [], :filepositions => filepositions || []}
end

#total_size ⇒ Object 



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# File 'lib/flvedit/processor/meta_data_maker.rb', line 14

def total_size
  @info.values.sum{|h| h.bytes + h.tag_count * TOTAL_EXTRA_SIZE_PER_TAG}
end