hpr-knowledge-base/hpr_transcripts/hpr2303.txt

Episode: 2303
Title: HPR2303: Kdenlive Part 5 All About Audio
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr2303/hpr2303.mp3
Transcribed: 2025-10-19 01:03:10

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This is HPR episode 2,303 entitled K-Men Live Part 5 all about audio.
It is posted against and is about 15 minutes long and carries a clean flag.
The summary is recording audio in K-Men Live.
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Hello again HPR listeners this is Gettys with you again with K-Men Live Part 5 all about audio.
The topics included are a brief discussion about the changing role of the modern day video
editor.
Better recording and synchronization best practices for a basic mix and lastly exporting.
Traditionally the film editing process was regimented and compartmentalized.
The assistant editors helped organize footage, the editor cut the picture, the sound engineer
mixed the soundtracks and the music composer provided the score.
In today's quickly evolving landscape of film production these roles are becoming
less clearly defined and many of these tasks are falling upon the editor alone and in
the independent world it's been this way for a very long time.
The results are that the video editor is responsible more and more for the building of the final
film from its disparate pieces and consolidating the tasks in this way tends to quicken the
post-production process and of course bring down costs.
Unfortunately since video editors have mostly been trained on video editing applications
they tend to try to perform all of those different tasks, clip organisation, dialogue
editing, audio cleaning and soundtrack mixing in the one application they are familiar
with, the video editor.
On canoe Linux we have the principle of modularity and the well-known idea that a tool should
do one thing and do it well.
KDN Live hardly does just one thing and even if we were to broaden the idea of what one
thing can mean it would still be a difficult argument to make that you were ever meant
to edit audio in a video editing application, open source or otherwise.
In this article we will discuss the different sources of audio, how to prepare it for editing,
how to export it, optimise it and finally re-import it.
Audio recording and synchronisation.
Most cameras that you will use will have some ability to capture sound but very rarely
are the microphones embedded in the camera a very good quality or at a reasonable distance
from the actors to capture good sound.
There are three scenarios that have become prominent in how to deal with this.
One, ignore the on board mic and set up an external recording system.
Two, ignore the on board mic and use an external mic recording into the camera.
Three, use the on board mic.
In the first case you will end up with separate audio files that you will import from the
external recording device such as zoom H4 or similar.
In the second case you will end up with audio embedded into the video file that you import
from the camera.
And in the third case you will still have embedded sound in the video file and you will
either use it as your only sound or you will use it as a reference sound while you sync
your external audio file to your video.
If you did record to an external device then you will need to synchronise sound in your
video editor.
This is easier if you did get the reference sound via the on board camera mic and it is
even easier if you actually bothered to slate each shot.
Slating is one of those often overlooked parts of production that is probably the single
most helpful thing you can do on set to aid in post-production.
A slate can be simple.
I find that a legal notepad open brackets like a tablet computer but made of trees belief
of it or not close brackets and a sharpie pen is perfect for the non-audible indication
of what scene, shot and take the clip is about to contain.
To give something to sync sound too easily make sure that both the camera and the sound
recording are rolling and then firmly clap your hands in clear view of the camera.
This is a low budget version of a clapboard and frankly it has the exact same results.
The only reason not to slate is because the shot is complex and there is literally no way
to fit a slate in at the beginning of the shot.
In this event do a tail slate that is the same thing only at the end of the shot.
It's customary to hold the notepad or clapboard or whatever upside down.
Just as a visual clue for the assistant editor or editor that this slate isn't indicating
that the shot is just beginning but that it's just ending.
If you slate each shot then synchronizing sound in your video editor is as simple as making
sure that your audio files and video files have same names, open brackets.
What on naming conventions in the final article of this series closed brackets?
Drag in them both into the timeline and lining up the loud sound of a clap in the audio
track with the visual of that clap in the video track.
Once it's synchronized, group the video and audio tracks together by selecting them both
with your select tool.
Right clicking on one track and choosing group clips.
If your sound is starting out synchronized but is then falling out of sync or just won't
sync at all then check the sample rate.
If your KDIN life project setting is 44.1 kHz or 48 kHz but your sound files are recorded
at 32 kHz or 22050Hz or worse then you might find that the audio simply isn't playing
at the correct speed.
It will gradually fall out of sync consistently regardless of how you move it or slice it.
Best practice for a basic mix.
Even though you'll be taking your audio out to an external application for the final mix,
the first draft of an audio mix happens within the video editor.
The best way to make this happen is to stay organized with what tracks receive what kind
of sound file.
You should plan on having at least two audio tracks for dialogue.
The first will be your default landing track for audio and the second you can use for
overlapping dialogue which sometimes happens in your typical over-the-shoulder conversation
scene.
In addition to these, you'll probably realistically want a track or two for sound effects.
While I don't want to do too much mixing in my video editor, I have to admit that sometimes
when editing a cafe scene, it just helps to have a bed of cafe background noises to
provide a little environment.
FreeSound.org is an excellent source for these kinds of effects.
So I often download a few tracks and sound effects and drop them into my effects and folly
tracks.
Even if I end up not using those particular sound effects, at least they serve as good
reference during the actual audio mix as to when the real versions of those effects should
come in and when they should end, think of it as a click track 2.0.
And finally, you might want to designate a track for music or musical elements.
Again, strictly speaking, this isn't something you should really be doing in a video editor.
But then again, we're not editing for Cecil B. DeMilli either.
Modern editors frequently edit to music and if nothing else, as with the effects, it will
serve as a good indication of when the real music is supposed to come in and when it should
swell and when it should be soft and so on.
Be sure not to mix different types of sound into the same tracks.
Look must stay with dialogue tracks, effects with effects tracks and music in music tracks.
If you do need to add a track and designate it as a third or fourth dialogue track, then
do so.
They're free, I promise.
At some point during your edit, you should separate the audio from the video tracks if
you are using any of the embedded sound streams that belong to a video track.
By doing so, you ensure that all of your audio is consolidated into the correct tracks
and it enables you to safely insecurity mute all sound of the video tracks which you'll
want to do if you are ignoring most of the embedded audio streams.
Export in.
The audio tracks for your project will not be exported for the final audio mix until you
have declared picture lock meaning that you've resolved that no changes to the sequence
of images will be made or that if they are made, then those changes will in no way require
shortening of the audio tracks, open brackets i.e. if you are swapping out one establishing
shot for another for the same duration and will not require any change to audio close
brackets.
Once you are secure that your picture is locked, then you can do a simple export via the
Render menu in KDN Live.
Access this via the big red button in the main toolbar or via the project menu Render.
The project menu for destination, choose audio only.
Select the format and sample rate you wish to export to.
It's best to stay with your current sample rate.
Make sure your output file is going to a logical directory and has a sensible name.
I usually place my audio tracks into a directory called mix.
You'll want to export each track as an individual file so in your timeline mute all tracks
but the first dialog track.
And then add it to the render queue by clicking the render to file button on the lower left
of the render dialog box.
This starts processing in the background so next you can mute the dialog track and
unmute your next track.
Name the output file and add it to your render queue.
Then mute that track and unmute the next one and so on.
In the end you'll have six audio tracks, assuming two dialogs, two effects and two music
that are each the full length of your project file.
There will probably be a lot of dead space in each since you may only have a sound effect
every few minutes or so or only one instance of music and so on.
The important thing is that each track is self-contained independent of the others and
all of them are exactly the same length as one another and as the video project itself.
You or your sound mixer can then import the audio files into an audio mix in application.
I've used audacity, outdoor and queue tractor for the job, mostly depending on what the
system I'm using happens to have installed or what the complexity of the project demands.
There's a little bit of expectation now that an audio mix in application will have
the ability to import a video track so that audio can be mixed exactly along with the video.
This certainly does help with sound queues or subtle sonic touches like noticing a passing
aeroplane outside a window and dropping in a faint aeroplane sound effect and so on.
At the time of this article the defractor audio mixers for Linux do not yet feature
disability out of the box.
One solution is a click track.
This is the time on it convention of having a spare audio track with either literal clicks
or in my personal version of a click track temporary sound effects that indicate when and
where some significant event is supposed to occur.
This combined with a low res temporary render of the movie that I can have open in Dragon
or Emplayer allows me to easily maneuver my audio mix and to cross reference the video
as needed.
So far I've not missed an audio queue yet and I feel that the absence of a constant
video track helps me immerse myself in the sound design.
The application XJDO allows you to bind a video file to the jack transport which is sort
of a meta playhead that synchronises various sound sources on a system.
Jack is usually used by musicians so that for instance the drum machine playing in hydrogen
will come in at the right moment in a sequence being designed in our door or queue tractor.
XJDO uses FFMPEG to playback a video in time and accordingly stop or scrub.
With your audio in any jack aware audio mixer.
Reimport in the mix once your sound is mixed to your liking you should export the sound
as a complete mix down.
Obviously you will keep the audio project itself in the event that you need to remix or change
the language or the dialogue i.e. for a dub track.
But I see no reason to allow KDN live to do any of the mix in by keeping the tracks separate.
Before importing the final mix into my project I generally save a copy of the project as,
for instance, project name underscore mix dot KDN live.
This I open in KDN live and eliminate the unneeded audio tracks.
Mostly just avoid silly mistakes but sometimes auto to save system resources.
Using the final mix is as easy as adding a clip to the project tree and then dragging
the final mix to a new audio track in the timeline starting at 0000000.
You have now successfully made the round trip with your audio mix.
And that's the end of KDN live part 5 all about audio.
In your comments and feedback are welcome and this has been Gettys for Hacker Public Radio
and I'll speak to you again in the last part, part 6.
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