Saves mp4 file as DVD or blueray image with audio increasingly out of sync.

[Skyblue]

I tried to make a dvd and blueray image out of one large mp4 file. Both images had the video audio fall out of sync. Original video plays fine. Why is that?

[lata]

What are the properties of the original video files?
Videos using a variable frame rate are susceptible to causing problems, Video Studio generally works with a constant frame rate.
Burning DVD or Bluray also use specific settings to comply with the industries standards sizes and frame rates.
Generally 25fps for pal and 29.97fps for NTSC

If you are intending to burn a disc then you are best to convert your project to the discs standards, Share Mpeg2 SD option for DVD or Share _MyDVD (1920 x 1080, 60i, 11Mbps) for BluRay
These are options taken from 2023, what version are you working with.
Use the resultant video files to burn the disc Share - Disc - DVD or Bluray

[Skyblue]

What are the properties of the original video files?
Videos using a variable frame rate are susceptible to causing problems, Video Studio generally works with a constant frame rate.
Burning DVD or Bluray also use specific settings to comply with the industries standards sizes and frame rates.
Generally 25fps for pal and 29.97fps for NTSC

If you are intending to burn a disc then you are best to convert your project to the discs standards, Share Mpeg2 SD option for DVD or Share _MyDVD (1920 x 1080, 60i, 11Mbps) for BluRay
These are options taken from 2023, what version are you working with.
Use the resultant video files to burn the disc Share - Disc - DVD or Bluray

I am using the 2018 version of VS. The mp4 file properties doesn't show if it's constant or variable frame rate. How is that decided? Right before exporting as DVD or Bluray image?

[lata]

Hi
Right click your video clip for properties.
A frame rate of 29.97fps or 30 fps is standard for ntsc video, 25 for pal
If the frame rate is different, example 29.83, any number other than 29.97 then it will be a variable rate.

There is an app called MediaInfo that gives full details of video properties, can be useful.

If we render and change the frame rate then frames will be added/removed, where variable frames are involved this may affect the audio content.
As a thought, sometimes deselecting Smart Render may help in fixing the audio shift, a bit of trial and error, unfortunately.

Where we feel that the program is struggling with a particular file, using a video converter to create a more editable format, one that VS likes, maybe the way to go.

[Skyblue]

What exactly does smart render do? Is it checked by default? When creating a video in VS from a project how do you determine if it is variable or constant? Can a video be switched afterwards?

[lata]

Hi
Smart Render is a process that speeds up the rendering, it works when the project properties match the videos being used, applying Smart Render to the sections of project that have NO edits applied, Filters, transitions etc.
Clips that have been changed get the full treatment taking a little longer to render.
When we convert a clip, say from 60 fps to 30 fps, smart render will have little effect as each frame needs to be fully rendered.
We do know that variable frame rates can cause issues and deselecting Smart Render has been known to fix things, in particular audio problems.

Variable Frame rates, these are usually used by iPhones to manage video file sizes.
Using Video Studio Share Options will use a constant frame rate.
If you right click your clip from the timeline or library, choose properties, a frame rate of 29.97fps is the standard rate and is constant.
If you see other rates like 29.88fps then those will be variable.
Using the MediaInfo app will give more details regarding the video properties including a Max and Minimum rate.

Typical settings
MPEG-4 Files
24 bits, 1080 x 1920, 29.989 fps is variable
Frame-based
H.265 Main 10 Profile Video: 23869 Kbps
48000 Hz, 16 Bit, Stereo
MPEG AAC Audio: 192 Kbps

[Skyblue]

I made the video I was trying to make a bluray with using VS which was made from a project. What would cause it to have variable speed?

[lata]

Variable speed video is created by iPhones whilst recording.

Bluray video is quite specific as to the video properties it uses, they have to comply with the industries standards for BD
When we burn a Bluray disc the program will convert our project / clips to what we call a compliant video, using this file to burn the disc.
We can test the process by choosing to create a Bluray Folder
These are the default settings, select the icon lower left - Project Settings

MPEG files
24 bits, 1920 x 1080, 29.97 fps
Upper Field First
(HDMV-NTSC), 16:9
Video data rate: Variable (Max. 35000 kbps)
Audio data rate: 384 kbps
Dolby Digital Audio, 48 KHz, 2/0(L,R)

We can customise some of these attributes, mainly the data rate.

After hitting Burn the process starts with Convert Title, this is rendering our project to use the above settings
When complete open the BDMV folder to view the Stream folder which contains your movie 0000.m2ts, drag this to the main timelines to check its properties.

We can avoid the Convert Title by first converting our project to the above settings ( or similar ) from Share - AVC/H.264 --AVC (1920 x 1080, 60i, 20Mbps)
Then using the resultant file to burn a disc
Some more info here.....
http://lata.me.uk/corel/all.htm


To burn a Bluray disc we have to use specific settings and those use a constant frame rate 29.97, they also have to be interlaced typically using upper field first.