[Requires QLab 4.1.2 or later]
This chapter deals with ways of importing markers from other programs, (including ProTools session markers), as slices in QLab and exporting slice markers from QLab for use with other programs.
Many of the examples use TwistedWave as the audio editor. It is beyond the resources of this article to test and provide solutions for every Mac audio editor. TwistedWave is a lightweight editor that is well suited for most audio editing tasks in conjunction with QLab, is reasonably priced and has a 30-day trial. Other editors may well provide similar capabilities with markers, but you will need to explore and test these yourself. Slice export from QLab methods described here produces standard .xml files that may work with other editors.
Example 1: Import markers in Twisted Wave as slices in QLab.
This is, to begin with, a straightforward process.
If you place markers in Twisted Wave and save the file they show up as slices in Qlab audio cues that target those files.
If you have markers that have been added in other programmes that Twisted Wave recognizes and displays as markers, those will work in exactly the same way.
For as long as the slices in the QLab cue and the audio file are the same, you can edit markers in the audio file and the QLab file will update immediately.
As soon as this is no longer the case the relationship breaks.
Things that will cause this to happen include;
• Any slice editing in the QLab cue
• Editing play counts in the QLab cue
• Editing the marker positions in the audio cue, when the workspace that has cues . that target the audio file is not open.
and there may well be others.
Once QLab decides the sync relationship is broken, then those slice marks will persist in that QLab cue forever unless deleted or moved. Retargeting an existing cue will not import any new markers as slices. And targeting a cue with no markers will not clear existing markers.
Example 2: Import markers from a ProTools session.
In ProTools markers are created in the session, on a ruler, rather than in individual audio files.
Bouncing down a workspace to an audio file does not include the session markers in the bounced audio file.
You can however through a slightly involved process get your session markers converted to audio markers that QLab will convert to slices when a cue is created that targets that audio.
Here’s the ProTools checklist
Ensure all markers are absolute (i.e not bar|beat)
Ensure your bounced or exported audio file starts at session time 0:00:00
Bounce or export your audio from ProTools to an audio file
Export session info as text (From the File menu) and deselect everything apart from Include Markers Time format should be Mins:Secs, Text Format should be TextEdit text.
The text file will look something like this:
You then need to open the audio file in an audio editor capable of recognising and parsing a ProTools session text file. (Twisted Wave will do nicely, and is used in this example).
In Twisted wave Import Markers…. from the Marker window, and select the session info text file from ProTools
Save the audio file, and you now have a markered file that QLab will convert to slices in the normal way.
Example 3: Import Chapters in a .mov file as slice markers to a QLab video cue
This opens the target video file of the selected cue in QuickTime Player, and sends the key combination to QuickTime player to step through the chapters until there are no more, gets each chapter time and puts a slice in the cue.
Here it is in action (Best viewed full screen):
How it works:
First we get the selected cue
We open it’s target (I am assuming it will open in the default for a video cue i.e QuickTime Player X)
We go to the next chapter mark (which will probably be chapter 2 as chapter 1 will start at the beginning of the file) by sending the right arrow keyed with command and shift keys down.
We get the current time of QuickTime Player.
Currently, there is no AppleScript to add a marker in QLab, but there is an OSC message that will do this. We use a shell script to send a plain text OSC message to localhost port 53535. (Port 53535 is a special QLab port which allows plain text to be used as an OSC message instead of properly formatted OSC messages which would be received on port 53000).
We then repeat this until the current time returned from QuickTime Player is the same as the previous iteration of the repeat loop, indicating there are no more chapters in the .mov file.
You can download the workspace here
Example 4; Export slice marker times from QLab to .xml file
This opens the targeted audio file of the selected cue in an audio editor, and if there are slice markers in the cue exports the slice number and it’s location both as samples and time to an .xml file, on the desktop, that can be read by Twisted Wave
How it works:
The script gets the selected cue from the QLab workspace
It opens the cue in the audio editor set at the top of the script
If there are slice markers in the cue then it counts them
It then gets the sample rate of the file. This is quite tricky as a lot of the AppleScript methods to do this don’t work as expected.
set sampleRate to do shell script “mdls ” & quoted form of POSIX path of thefile & ” | grep \”kMDItemAudioSampleRate\” | awk ‘{print $3}'” works and can also be applied to other multimedia file types
We need the sample rate so we can include the sample number for the position of the marker in the .xml file
We then construct the contents and formatting of the .xml file which looks like this
and output it to an .xml file, on the desktop, named so as to identify which file it refers to e,g
PNO Finale PNOSHORT.wavMarkers.xml
This can then be imported into Twisted Wave. In Twisted wave Import Markers…. from the Marker window, and select the .xml file. When the file is saved in TwistedWave the markers are then embedded for use in future cues. TwistedWave can also split a file by markers so you can easily create a file for each section between slices.
You can download the workspace here
Chapter Author: Mic Pool
Chapter Graphic: based on a photo by Kkdu101 sourced from commons wikipedia.org licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.
Modified image redistributed under the same license
All Trade Marks Acknowledged
TwistedWave is a registered trade mark of TwistedWave Software LTD. 398 – 2416 Main street Vancouver B.C. V5T 3E2 Canada
ProTools is a registered trade mark of Avid Technology, Inc