.MTS file de-sync upon import (VP23 - 302)

Chris-Watson wrote on 11/12/2025, 4:59 PM

Long-time Vegas Pro user, but first-time forum user - please go easy!

Here's the issue: all of a sudden, using VP23 (Build 302) .MTS files, upon importing to the timeline suffer an audio and video slip by 17 frames (video is 17 frames ahead of audio). Occasionally, clips appears on the timeline with an overhang (the video visibly extends 17 frames beyond the audio), in which case the sync is correct.

Yes, I can correct this with time-consuming manual re-slipping, or Handbrake conversion using the Constant Framerate option, despite the footage already being CFR. Both solutions are not tenable for me due to volume of clips I deal with and time constraints. My 4K files are unaffected.

I've thoroughly experimented with enable/disable legacy AVC encoding but with no result.

My work is solely multicamera concert shoots and I rely on a number of older HD camcorders for those extra angles (with 4K prosumer cams doing the bulk of the work).

After 12+ years without problems, this is suddenly an issue. Has anyone encountered this before? - please help!

These are the specs of the problem files:

General
  Name: 00002.MTS
  Folder: E:\[........................]
  Type: Blu-Ray Transport Stream
  Size: 2.08 GB (2,125,627,392 bytes)
  Created: Wednesday, November 12, 2025, 1:33:41 PM
  Modified: Wednesday, January 1, 2014, 6:02:54 AM
  Accessed: Thursday, November 13, 2025, 11:41:30 AM
  Attributes: Archive

Media information
  Stream format: BDAV
  Video stream #1
    Video format: AVC
    Resolution: 1920 x 1080 px
    Aspect ratio: 16:9
    Color depth: 8 bit
    Frame rate: 25.000 fps
    Scan type: Interlaced
    Bit rate mode: Variable
    Bit rate: 21318375 bps
  Audio stream #1
    Audio format: AC-3
    Sampling rate: 48000 Hz
    Channels: 2 channels
    Bit rate mode: Constant
    Bit rate: 256000 bps

Streams
  Video: 00:12:36.600, 25.000 fps progressive, 1920x1080x32, AVC
  Audio: 00:12:36.576, 48000 Hz, 16 Bits, Stereo, AC-3

ACID information
  ACID chunk: no
  Stretch chunk: no
  Stretch list: no
  Stretch info2: no
  Beat markers: no
  Detected beats: no

Other metadata
  Regions/markers: no
  Command markers: no

Media manager
  Media tags: no

Plug-In
  Name: mxcompoundplug.dll
  Folder: C:\Program Files\VEGAS\VEGAS Pro 23.0\FileIO Plug-Ins\mxcompoundplug
  Format: MAGIX HEVC
  Version: Version 23.0 (Build 302)
  Company: MAGIX Computer Products Intl. Co.

 

COMPUTER SPECS - using Win 11:

Device name    DESKTOP-THRIB3O
Processor    Intel(R) Core(TM) i9-10980XE CPU @ 3.00GHz (3.00 GHz)
Installed RAM    128 GB (128 GB usable)
Device ID    8E94D27C-DA06-45D4-9340-8442D2BBF320
Product ID    00330-80014-41236-AA324
System type    64-bit operating system, x64-based processor
Pen and touch    No pen or touch input is available for this display
 

Comments

EricLNZ wrote on 11/12/2025, 5:29 PM

AC-3 audio. I wonder if that's the problem? Is your Win11 a fresh install? If so VP23 is presumably using its new decoder for AC-3 as Windows no longer provides one.

Another thought - do you have any codec packs installed?

Chris-Watson wrote on 11/12/2025, 7:39 PM

Thanks Eric (and greetings from Wgtn - I see your pohutukawa!).

My Win11 was a fresh install back in June (24H2) and I moved from VP22 to VP23 about a month back, with no problems until yesterday. The AC-3 audio is playing just fine in Vegas, the only problem being that it's 17 frames out of sync with the video.

Regardless, following your hunch, I have installed the K-Lite codec pack and restarted several times. But no improvement, sadly.

Are there any other things that occur to you?

Your help is greatly appreciated - thanks for taking the time!

EricLNZ wrote on 11/12/2025, 8:03 PM

Hi, Auckland here.

Installing K-Lite is usually not recommended as it can conflict with VP's codecs.

Can you shoot a short clip of something say a minute long. Check it still has the problem and then post somewhere like Google drive. Others can then download to see if they have the same problem and if so the file can be forwarded to Vegas developers. Thanks.