Class: RVideo::Inspector

Inherits:
Object
  • Object
show all
Defined in:
lib/rvideo/inspector.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Inspector

To inspect a video or audio file, initialize an Inspector object.

file = RVideo::Inspector.new(options_hash)

Inspector accepts three options: file, raw_response, and ffmpeg_binary. Either raw_response or file is required; ffmpeg binary is optional.

:file is a path to a file to be inspected.

:raw_response is the full output of “ffmpeg -i [file]”. If the :raw_response option is used, RVideo will not actually inspect a file; it will simply parse the provided response. This is useful if your application has already collected the ffmpeg -i response, and you don’t want to call it again.

:ffmpeg_binary is an optional argument that specifies the path to the ffmpeg binary to be used. If a path is not explicitly declared, RVideo will assume that ffmpeg exists in the Unix path. Type “which ffmpeg” to check if ffmpeg is installed and exists in your operating system’s path.



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# File 'lib/rvideo/inspector.rb', line 30

def initialize(options = {})
  if options[:raw_response]
    @raw_response = options[:raw_response]
  elsif options[:file]
    if options[:ffmpeg_binary]
      @ffmpeg_binary = options[:ffmpeg_binary]
      raise RuntimeError, "ffmpeg could not be found (trying #{@ffmpeg_binary})" unless FileTest.exist?(@ffmpeg_binary)
    else
      # assume it is in the unix path
      raise RuntimeError, 'ffmpeg could not be found (expected ffmpeg to be found in the Unix path)' unless FileTest.exist?(`which ffmpeg`.chomp)
      @ffmpeg_binary = "ffmpeg"
    end

    file = options[:file]
    @filename = File.basename(file)
    @path = File.dirname(file)
    @full_filename = file
    raise TranscoderError::InputFileNotFound, "File not found (#{file})" unless FileTest.exist?(file.gsub("\"",""))
    @raw_response = `#{@ffmpeg_binary} -i #{@full_filename} 2>&1`
  else
    raise ArgumentError, "Must supply either an input file or a pregenerated response" if options[:raw_response].nil? and file.nil?
  end

  metadata = metadata_regexp.match(@raw_response)
  
  if /Unknown format/i.match(@raw_response) || metadata.nil?
    @unknown_format = true
  elsif /Duration: N\/A/im.match(@raw_response)
#      elsif /Duration: N\/A|bitrate: N\/A/im.match(@raw_response)
    @unreadable_file = true
    @raw_metadata = metadata[1] # in this case, we can at least still get the container type
  else
    @raw_metadata = metadata[1]
  end
end

Instance Attribute Details

#ffmpeg_binary ⇒ Object

Returns the value of attribute ffmpeg_binary.



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# File 'lib/rvideo/inspector.rb', line 6

def ffmpeg_binary
  @ffmpeg_binary
end

#filename ⇒ Object (readonly)

Returns the value of attribute filename.



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# File 'lib/rvideo/inspector.rb', line 4

def filename
  @filename
end

#full_filename ⇒ Object (readonly)

Returns the value of attribute full_filename.



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# File 'lib/rvideo/inspector.rb', line 4

def full_filename
  @full_filename
end

#path ⇒ Object (readonly)

Returns the value of attribute path.



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# File 'lib/rvideo/inspector.rb', line 4

def path
  @path
end

#raw_metadata ⇒ Object (readonly)

Returns the value of attribute raw_metadata.



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# File 'lib/rvideo/inspector.rb', line 4

def raw_metadata
  @raw_metadata
end

#raw_response ⇒ Object (readonly)

Returns the value of attribute raw_response.



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# File 'lib/rvideo/inspector.rb', line 4

def raw_response
  @raw_response
end

Instance Method Details

#audio? ⇒ Boolean

Does the file have an audio stream?

Returns:

  • (Boolean) 


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# File 'lib/rvideo/inspector.rb', line 114

def audio?
  if audio_match.nil?
    false
  else
    true
  end
end

#audio_bit_rate ⇒ Object

:nodoc:



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# File 'lib/rvideo/inspector.rb', line 338

def audio_bit_rate # :nodoc:
  nil
end

#audio_channels ⇒ Object 



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# File 'lib/rvideo/inspector.rb', line 407

def audio_channels
  return nil unless audio?

  case audio_match[5]
  when "mono"
    1
  when "stereo"
    2
  else
    raise RuntimeError, "Unknown number of channels: #{audio_channels}"
  end
end

#audio_channels_string ⇒ Object

The channels used in the audio stream.

Examples:

"stereo"
"mono"
"5:1"



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# File 'lib/rvideo/inspector.rb', line 401

def audio_channels_string
  return nil unless audio?
  
  audio_match[5]
end

#audio_codec ⇒ Object

The audio codec used.

Example:

"aac"



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# File 'lib/rvideo/inspector.rb', line 358

def audio_codec
  return nil unless audio?
  
  audio_match[2]
end

#audio_sample_rate ⇒ Object

The sampling rate of the audio stream.

Example:

44100



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# File 'lib/rvideo/inspector.rb', line 372

def audio_sample_rate
  return nil unless audio?
  
  audio_match[3].to_i
end

#audio_sample_units ⇒ Object

The units used for the sampling rate. May always be Hz.

Example:

"Hz"



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# File 'lib/rvideo/inspector.rb', line 386

def audio_sample_units
  return nil unless audio?
  
  audio_match[4]
end

#audio_stream ⇒ Object 



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# File 'lib/rvideo/inspector.rb', line 342

def audio_stream
  return nil unless valid?
  
  #/\n\s*Stream.*Audio:.*\n/.match(@raw_response)[0].strip
  match = /\n\s*Stream.*Audio:.*\n/.match(@raw_response)
  return match[0].strip if match
end

#audio_stream_id ⇒ Object

The ID of the audio stream (useful for troubleshooting).

Example:

#0.1



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# File 'lib/rvideo/inspector.rb', line 427

def audio_stream_id
  return nil unless audio?
  
  audio_match[1]
end

#bitrate ⇒ Object

The bitrate of the movie.

Example:

3132



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# File 'lib/rvideo/inspector.rb', line 318

def bitrate
  return nil unless valid?
  
  bitrate_match[1].to_i
end

#bitrate_units ⇒ Object

The bitrate units used. In practice, this may always be kb/s.

Example:

"kb/s"



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# File 'lib/rvideo/inspector.rb', line 332

def bitrate_units
  return nil unless valid?
  
  bitrate_match[2]
end

#calculate_time(timecode) ⇒ Object 



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# File 'lib/rvideo/inspector.rb', line 181

def calculate_time(timecode)
  m = /\A([0-9\.\,]*)(s|f|%)?\Z/.match(timecode)
  if m.nil? or m[1].nil? or m[1].empty?
    raise TranscoderError::ParameterError, "Invalid timecode for frame capture: #{timecode}. Must be a number, optionally followed by s, f, or %."
  end
  
  case m[2]
  when "s", nil
    t = m[1].to_f
  when "f"
    t = m[1].to_f / fps.to_f
  when "%"
    # milliseconds / 1000 * percent / 100 
    t = (duration.to_i / 1000.0) * (m[1].to_f / 100.0)
  else
    raise TranscoderError::ParameterError, "Invalid timecode for frame capture: #{timecode}. Must be a number, optionally followed by s, f, or p."
  end
  
  if (t * 1000) > duration
    calculate_time("99%")
  else
    t
  end
end

#capture_frame(timecode, output_file = nil) ⇒ Object

Take a screengrab of a movie. Requires an input file and a time parameter, and optionally takes an output filename. If no output filename is specfied, constructs one.

Three types of time parameters are accepted - percentage (e.g. 3%), time in seconds (e.g. 60 seconds), and raw frame (e.g. 37). Will raise an exception if the time in seconds or the frame are out of the bounds of the input file.

Types:

37s (37 seconds)
37f (frame 37)
37% (37 percent)
37  (default to seconds)

If a time is outside of the duration of the file, it will choose a frame at the 99% mark.

Example:

t = RVideo::Transcoder.new('path/to/input_file.mp4')
t.capture_frame('10%') # => '/path/to/screenshot/input-10p.jpg'



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# File 'lib/rvideo/inspector.rb', line 166

def capture_frame(timecode, output_file = nil)
  t = calculate_time(timecode)
  unless output_file
    output_file = "#{TEMP_PATH}/#{File.basename(@full_filename, ".*")}-#{timecode.gsub("%","p")}.jpg"
  end
  # do the work
  # mplayer $input_file$ -ss $start_time$ -frames 1 -vo jpeg -o $output_file$
  # ffmpeg -i $input_file$ -v nopb -ss $start_time$ -b $bitrate$ -an -vframes 1 -y $output_file$
  command = "ffmpeg -i #{@full_filename} -ss #{t} -t 00:00:01 -r 1 -vframes 1 -f image2 #{output_file}"
  Transcoder.logger.info("\nCreating Screenshot: #{command}\n")
  frame_result = `#{command} 2>&1`
  Transcoder.logger.info("\nScreenshot results: #{frame_result}")
  output_file
end

#container ⇒ Object

Returns the container format for the file. Instead of returning a single format, this may return a string of related formats.

Examples:

"avi"

"mov,mp4,m4a,3gp,3g2,mj2"



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# File 'lib/rvideo/inspector.rb', line 272

def container
  return nil if @unknown_format
  
  /Input \#\d+\,\s*(\S+),\s*from/.match(@raw_metadata)[1]
end

#duration ⇒ Object

The duration of the movie in milliseconds, as an integer.

Example: 

24400         # 24.4 seconds

Note that the precision of the duration is in tenths of a second, not thousandths, but milliseconds are a more standard unit of time than deciseconds.



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# File 'lib/rvideo/inspector.rb', line 303

def duration
  return nil unless valid?
  
  units = raw_duration.split(":")
  (units[0].to_i * 60 * 60 * 1000) + (units[1].to_i * 60 * 1000) + (units[2].to_f * 1000).to_i
end

#ffmpeg_build ⇒ Object

Returns the build description for ffmpeg.

Example:

built on Apr 15 2006 04:58:19, gcc: 4.0.1 (Apple Computer, Inc. build
  5250)



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# File 'lib/rvideo/inspector.rb', line 257

def ffmpeg_build
  /(\n\s*)(built on.*)(\n)/.match(@raw_response)[2]
end

#ffmpeg_configuration ⇒ Object

Returns the configuration options used to build ffmpeg.

Example:

--enable-mp3lame --enable-gpl --disable-ffplay --disable-ffserver
  --enable-a52 --enable-xvid



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# File 'lib/rvideo/inspector.rb', line 229

def ffmpeg_configuration 
  /(\s*configuration:)(.*)\n/.match(@raw_response)[2].strip
end

#ffmpeg_libav ⇒ Object

Returns the versions of libavutil, libavcodec, and libavformat used by ffmpeg.

Example:

libavutil version: 49.0.0
libavcodec version: 51.9.0
libavformat version: 50.4.0



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# File 'lib/rvideo/inspector.rb', line 244

def ffmpeg_libav
  /^(\s*lib.*\n)+/.match(@raw_response)[0].split("\n").each {|l| l.strip! }
end

#ffmpeg_version ⇒ Object

Returns the version of ffmpeg used, In practice, this may or may not be useful.

Examples:

SVN-r6399
CVS



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# File 'lib/rvideo/inspector.rb', line 216

def ffmpeg_version
  @ffmpeg_version = @raw_response.split("\n").first.split("version").last.split(",").first.strip
end

#fps ⇒ Object

The frame rate of the video in frames per second

Example:

"29.97"



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# File 'lib/rvideo/inspector.rb', line 524

def fps
  return nil unless video?
  
  /([0-9\.]+) (fps|tb)/.match(video_stream)[1]
end

#height ⇒ Object

The height of the video in pixels.



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# File 'lib/rvideo/inspector.rb', line 496

def height
  return nil unless video?
  
  video_match[5].to_i
end

#invalid? ⇒ Boolean

Returns false if the file can be read successfully. Returns false otherwise.

Returns:

  • (Boolean) 


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# File 'lib/rvideo/inspector.rb', line 82

def invalid?
  !valid?
end

#metadata_regexp ⇒ Object

Returns a match regexp appropriate to the version of ffmpeg in use



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# File 'lib/rvideo/inspector.rb', line 138

def metadata_regexp
  case ffmpeg_version
  when "SVN-r18077"
    /(Input \#.*)\nAt/m
  else
    /(Input \#.*)\nMust/m
  end
end

#raw_duration ⇒ Object

The duration of the movie, as a string.

Example:

"00:00:24.4"  # 24.4 seconds



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# File 'lib/rvideo/inspector.rb', line 285

def raw_duration
  return nil unless valid?
  
  /Duration:\s*([0-9\:\.]+),/.match(@raw_metadata)[1]
end

#resolution ⇒ Object

width x height, as a string.

Examples:

320x240
1280x720



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# File 'lib/rvideo/inspector.rb', line 510

def resolution
  return nil unless video?
  
  "#{width}x#{height}"
end

#unknown_format? ⇒ Boolean

True if the format is not understood (“Unknown Format”)

Returns:

  • (Boolean) 


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# File 'lib/rvideo/inspector.rb', line 90

def unknown_format?
  if @unknown_format
    true
  else
    false
  end
end

#unreadable_file? ⇒ Boolean

True if the file is not readable (“Duration: N/A, bitrate: N/A”)

Returns:

  • (Boolean) 


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# File 'lib/rvideo/inspector.rb', line 102

def unreadable_file?
  if @unreadable_file
    true
  else
    false
  end
end

#valid? ⇒ Boolean

Returns true if the file can be read successfully. Returns false otherwise.

Returns:

  • (Boolean) 


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# File 'lib/rvideo/inspector.rb', line 70

def valid?
  if @unknown_format or @unreadable_file
    false
  else
    true
  end
end

#video? ⇒ Boolean

Does the file have a video stream?

Returns:

  • (Boolean) 


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# File 'lib/rvideo/inspector.rb', line 126

def video?
  if video_match.nil?
    false
  else
    true
  end
end

#video_codec ⇒ Object

The video codec used.

Example:

"mpeg4"



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# File 'lib/rvideo/inspector.rb', line 462

def video_codec
  return nil unless video?
  
  video_match[2]
end

#video_colorspace ⇒ Object

The colorspace of the video stream.

Example:

"yuv420p"



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# File 'lib/rvideo/inspector.rb', line 476

def video_colorspace
  return nil unless video?
  
  video_match[3]
end

#video_stream ⇒ Object 



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# File 'lib/rvideo/inspector.rb', line 433

def video_stream
  return nil unless valid?
  
  match = /\n\s*Stream.*Video:.*\n/.match(@raw_response)
  return match[0].strip unless match.nil?
  nil
end

#video_stream_id ⇒ Object

The ID of the video stream (useful for troubleshooting).

Example:

#0.0



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# File 'lib/rvideo/inspector.rb', line 448

def video_stream_id
  return nil unless video?
  
  video_match[1]
end

#width ⇒ Object

The width of the video in pixels.



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# File 'lib/rvideo/inspector.rb', line 486

def width
  return nil unless video?
  
  video_match[4].to_i
end