VLC fails to convert DVD with 2 layers

I am using the current version of VLC (3.0.16) and found that it would fail when it converts the DVD to files (I tried mp4 / mkv) and when the DVD needs to switch from layer 1 to layer 2.

The convert would be successful if:

• The DVD is single layer;
• If I stop the convert when the DVD needs to switch layer;
• If I begin the convert from the 2nd layer, e.g. if I know that chapter 14 is the 1st chapter of the 2nd layer, and I begin to convert from 14th chapter.

The convert would fail if:

• The DVD is dual layer, and I try to convert the DVD starting from the 1st layer and continue to the 2nd layer.

When the DVD switches to 2nd layer, the VLC will only be able to display black screen, but the audio part seems to be working fine. After couple mins the VLC app will fail too.

If I use the same computer to play the DVD using VLC, not convert to file, the whole disc can be played correctly and the DVD changes layer without causing problem to VLC.

Thus, it seems to me that the VLC fails to handle DVD layer changes - when it is used to convert the dual layer DVDs into files.

Further findings:

• If a single layer DVD is long (e.g. > 80 mins), it has higher chance of failing towards the end of the DVD. The VLC app will crash, leaving a .mkv file usually not usable. If the file could be open by VLC (not other apps) some times, the file usually have the final bits with out of sync video / audio, or there is no video at all just sound.
• All the DVDs I tested on VLC and failed, can be extracted without issue with MakeMKV for both 1 & 2 layer(s) DVDs.

(The same problem happens to my MacBook Air too on VLC Mac version with external LG DVD drive. It plays the DVD fine, but fails at layer change when convert DVD to files.)

Link to VLC forum: https://forum.videolan.org/viewtopic.php?f=14&t=158573