Joining several AVI files with progressive audio delay + converting to MKV

[motorola8800]

I have a set of 8 AVI files - mediainfo details below.

I am using VSDC and encoding with the hardware accelerated NVIDIA H265 profile (Normal quality CRF 30 AAC 192) into a single MKV file

The individual AVI files all have a progressive audio delay ranging from 1-2 seconds. If I alter the frame rate with the AVI Frame Rate Adjust v1.00 tool from 30 to 29.8 this corrects the delay. But adding those corrected AVI files to the MKV workflow above still results in an out of sync MKV.

Is there a better solution to this problem? Should I change the framerate from within the VSDC encoder profile and not alter the AVI files beforehand, or is there a better way of pre treating the AVI files before I load them up into the VSDC timeline? Note the audio delay problem is not constant, it starts off at about 1 second and progressively drifts towards 2 seconds towards the end of each 5 min AVI file.


General
Complete name : MOV00000.AVI
Format : AVI
Format/Info : Audio Video Interleave
File size : 823 MiB
Duration : 5 min 2 s
Overall bit rate : 22.9 Mb/s


Video
ID : 0
Format : JPEG
Codec ID : MJPG
Duration : 5 min 2 s
Bit rate : 22.3 Mb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate : 30.000 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.360
Stream size : 802 MiB (97%)

Audio
ID : 1
Format : PCM
Format settings : Little / Signed
Codec ID : 1
Duration : 5 min 1 s
Bit rate mode : Constant
Bit rate : 512 kb/s
Channel(s) : 1 channel
Sampling rate : 32.0 kHz
Bit depth : 16 bits
Stream size : 18.4 MiB (2%)
Alignment : Aligned on interleaves
Interleave, duration : 1004 ms (29.91 video frames)

[ProWo]

Try to encode with 29.97fps

[motorola8800]

That didn’t help I’m afraid but thanks for the suggestion.

[pcspeak]

Hi.
With 'AVI Frame Rate Adjust' tool it looks like the change to the audio is only written in the header. Nothing is changed in the video/audio stream.
That info is not being honored by VSDC.
I wrote this batch file. You'll need ffmpeg.exe in the folder with the batch file and videos.
Might be worth experimenting with. If the video starts playing with a 1 second audio delay and then drifts out to 2 seconds then you may get a video out with matching start times.
I'm not saying the drift won't happen.
Drag and drop a video onto the batch file.

AUDIO Delay DROP v02.cmd

@echo off
if not exist NEW\*.* md NEW

echo.
echo  Output will be in the \NEW folder.
echo  Enter the figure in "seconds.milliseconds"
echo  with a plus or minus sign in front.
echo.
echo  The change can be negative or positive.
echo  e.g.
echo  -0.500  -^> half a second
echo  -0.250  -^> a quarter of a second
echo  +0.280  -^> two hundred and eighty milliseconds
echo  +1.500  -^> one and a half seconds
echo.
echo  If the audio is playing too late use negative.
echo  If the audio is playing too soon use positive.
set /p offset=Enter the change:

:Loop
ffmpeg.exe -i %1 -itsoffset %offset% -i %1 -vcodec copy -acodec copy -map 0:0 -map 1:1  -y "NEW\%~nx1"
shift
if not %1=="" goto :Loop

There are a number of converters here.
https://topalter.com/windows/46112/avi-frame-rate-changer/alternatives

Maybe one of them will do what you want.
Have fun.

Cheers