Issues With Audio Sync


#1

Essentially, I need Shotcut to do minor edits to footage from my Twitch streams to put on YouTube. When playing through media player directly from my folder, every file is synced. As soon as I load it into Shotcut, it is off by I’d estimated 0.25-0.5 seconds. It is super noticeable and is making my gameplay footage and facecam look like a badly synced martial arts film.

How do I go about sorting this out? This is really bugging me and is now delaying any more of my videos going up on YouTube.

Just want to add that it doesn’t appear to be the length of the video. My first episode of KH2 and all previous videos are in sync. It’s only been doing this since ep 2 of KH2, and every episode since has been shorter than ep 1.


#2

Are the files Variable Frame Rate? If so, convert them to edit-friendly format before editing.

In the Properties panel, click on the Hamburger Menu and then choose “Convert to Edit friendly”. Is the lipsync better after the conversion?


#3

Go to the properties panel, select the Audio tab and use the Sync slider to correct it.
But if your video is Variable Frame Rate Shotcut doesn’t support it.


#4

Does this actually create a constant framerate version?


#5

But do you have any idea why it is doing this in the first place? Every video up until KH2 episode 1, stays in sync. All of a sudden, it no longer loads mp4s that I have recorded in sync. In my mind, there is no reason why that should happen, so is there anything I am missing?


#6

I expect so. At least that is the intention.


#7

I don’t know. What software are you using for capture? OBS? Maybe you upgraded the software or changed a setting accidentally?


#8

I’m not sure. The more I look into it, the more confusing it gets. Eps 1 and 3 are both fine, but 2 and 4 are out of sync. 5 was out of sync, but with your help, I have sorted ep 5 out. So now I don’t know if it is Shotcut randomly messing up, or if it is OBS, but if it was OBS, you’d think it would be out of sync when playing back before loading into Shotcut, no?


#9

What you haven’t answered is the question of if your files are VBR??


#10

A, because I am a scrub and have no idea what you mean, and b, because I managed to fix the sync on my latest video so I presume they aren’t as you said they wouldn’t be supported if they were.


#11

Download and install a program called Media Info, the current version is 17.12.
Install Media info and once installed run it.
A window will come up - make sure that explorer shell integration is checked.
Close any windows that have now been subsequently opened by media info.
Browse to the folder where your media file is, then right click on it and select Mediainfo from the menu.
In media info select the view option and then tree.
As you scroll down you will find the video section, approximately 20 lines down in this section should be an entry that says “Frame Rate Mode” - this will say Variable or Constant if it says Variable it is unsupported by Shotcut and will need to be converted to a fixed frame rate.

Hope this helps.


#12

Shotcut has its own detection of Variable Frame Rate that can give different results than Media Info. All you need to do is open the file in Shotcut, click Properties, and view the frame rate. If there is “(variable)” after the numbers, then it is variable frame rate. See the screenshot on the v17.12 blog post.


#13

Using Shotcut v 18.03.06 ( 18.05.08 crashed when it started so i downgraded)

I just finished a 5 minute compilation that has 3 layers of video, 2 audio tracks, 78 video snippets.
The exported video audio sync problem was driving me crazy for over 6 hours.

The source vids are reported as 60 fps in VLC but 62.5 fps in ShotCut (Properties) ???
Not sure what to make of that difference so I experimented…
After trying all the suggestions here as well as coding the final output at 62.5, 60, 30 and 25fps(default), I found the fix.
I simply set frame rate to 25fps and the Codec and Audio to ConstantBitrate.
(NOTE: this rate does NOT match the native frame rate of the videos)

Here’s what finally worked for me:
BTW: I converted the MP3 file to .WAV for music track (not sure if it made a difference, but someone suggested it)

SETTINGS:
Video: 1920 x 1080 , 16:9 , 25 fps

Codec: libx264 , Rate Control: ConstantBitrate, bitrate 2Mb/s, BufferSize 224.00 Kb

Audio: 48000, aac, ConstantBitrate, bitrate 384K

As you can see in the final result, the timing was critical and a sync error of just a few frames would ruin the effect:
2018 Florida Gators Dance Hall Edition


#14

@Chasse_Court thank you, it will help other users that the tool is called “MediaInfo” (one word) and I found it here https://www.heise.de/download/product/mediainfo-57451 (a reliable programs list I use a lot) as mediainfo_gui_18.05_windows.exe (so is now Version 18.05).

Our team is having random-looking sync issues and having more data will help for sure.