# Ruby/GStreamer and querying file duration

**URL:** <https://www.ruby-forum.com/t/ruby-gstreamer-and-querying-file-duration/185869>\
**Category:** Ruby-Gnome 2\
**Created:** [March 27, 2010, 10:15pm UTC](https://www.ruby-forum.com/t/ruby-gstreamer-and-querying-file-duration/185869 "2010-03-27T22:15:56Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Marcin\_L](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/df788c/32.png) [@Marcin\_L](https://www.ruby-forum.com/u/Marcin_L)\
**Post date:** [March 27, 2010, 10:15pm UTC](https://www.ruby-forum.com/t/ruby-gstreamer-and-querying-file-duration/185869/1 "2010-03-27T22:15:56Z")

</div>

Hi,

can anyone provide working example for querying duration of an audio  
file  
using Ruby/GStreamer?

Code in gstreamer/src/samples/ is completely outdated and IMHO should be  
removed from the repository.

I attach my current code below, but I always got an error like  
“Gst::QueryType::Type isn’t supported”, doesn’t matter what kind of  
query I  
pass to pad.query. Even if I pass attributes taken from pad.query\_types!  
It  
seems that’s a bug?

–  
m.

CODE:

#!/usr/bin/ruby  
require ‘gst’

Gst.init

class DurationMeter  
def initialize  
@pipeline = Gst::Pipeline.new(“durationmeter”)

```
@source = Gst::ElementFactory.make("filesrc")
@source.location = ARGV[0]

@convertor = Gst::ElementFactory.make("audioconvert")

@sink = Gst::ElementFactory.make("fakesink")

@decoder = Gst::ElementFactory.make("decodebin")
@decoder.signal_connect("new-decoded-pad") do | dbin, pad, is_last |
  pad.link @convertor.get_pad("sink")
  @convertor >> @sink

  @sinkpad = @sink.get_pad("sink")
  @sinkpad.signal_connect("notify::caps") do |pad, args|
    if pad.negotiated_caps
      puts pad.query Gst::QueryType::DURATION

    end
  end
end

@pipeline.add @source, @decoder, @convertor, @sink
@source >> @decoder

@pipeline.bus.add_watch do | bus, message |
  case message.type
    when Gst::Message::Type::ERROR
      puts "Error"
      puts message.structure["debug"]

      @pipeline.stop

      exit 1

    when Gst::Message::Type::EOS
      puts "EOS"
      @pipeline.stop
      exit 0

    when Gst::Message::Type::ELEMENT
      puts "Message from #{message.source.name}"
  end
  true
end

```

end

def play  
@pipeline.play  
end

def stop  
@pipeline.stop  
end  
end

meter = DurationMeter.new  
meter.play

mainloop = GLib::MainLoop.new GLib::MainContext.default, true  
mainloop.run

---

<div class="post-metadata">

**Author:** ![Marcin\_L](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/df788c/32.png) [@Marcin\_L](https://www.ruby-forum.com/u/Marcin_L)\
**Post date:** [March 27, 2010, 11:08pm UTC](https://www.ruby-forum.com/t/ruby-gstreamer-and-querying-file-duration/185869/2 "2010-03-27T23:08:01Z")

</div>

OK, I found that.

Proof-of-concept app is submitted to the hiki:  
[http://ruby-gnome2.sourceforge.jp/hiki.cgi?gst-duration-seek-position](http://ruby-gnome2.sourceforge.jp/hiki.cgi?gst-duration-seek-position)

m.