I have an HP laptop that has MX350 graphics card and the screen is 60 hz. I used Aegisub 3.4.0 to fix the timing of the subtitle lines. I set the end time and I pressed d to listen to the last 500ms of the line and I pressed w to listen to 500ms after the end time. If I had set the end time to be too early then I will hear the ending of the last spoken word when I pressed w thus I have to advance the end time. After that I pressed ctrl and p to play the line. If I couldn’t tell if I line ended exactly when I heard it and I don’t know if it exactly ended when a person stopped speaking or a bit before then that means that the end time is too close so I added a .05ms delay to the end time so it became obvious that the line ended exactly when the person stopped speaking.
I am using MPC-HC with madVR on the HP laptop. I played the movie in MPC-HC to verify the timing of the lines. If there were any issues in the timing then I fixed them in Aegisub and I replayed that part again in MPC-HC. I had fixed the timing of 12 subtitle files. There were no issues when I played the movies on the HP laptop.
I bought a Lenovo laptop that has a RTX 4090 graphics card and the screen is 240 hz. I also used MPC-HC with madVR on the new laptop. The problem is that I when I played those movies on the Lenovo laptop in MPC-HC then for a lot of the lines it sounded as if they ended before the person stopped speaking but there is no problem when I pressed w in Aegisub on the Lenovo laptop. I tested the movies in SM Player and also by playing them in Aegisub by pressing ctrl p. The problem is there. Also, the problem is other movies that I had previously fixed their subtitle files.
In the beginning I thought that the problem happened because the Lenovo laptop is more powerful than the HP laptop and 240 hz is faster than 60 hz so it made the timing issues more obvious because the lines are played a bit faster on the Lenovo laptop. I had to again fix the timing of the lines on the new laptop and I again add a delay to the end time so the problem went away and it became obvious that the line ended exactly when the person stopped speaking.
I uninstalled FxSound on the Lenovo laptop and I switched to using SM player because it has better audio normalization. I tested a couple of movies that I know had the problem before and I saw that the problem went away and the subtitle lines went away exactly when the person stopped speaking. So then is FxSound the reason for the problem?
The video, audio and subtitles should immediately start when I play a movie. FxSound has to process the audio so I think it will add a small delay like 20ms so the audio won’t immediately start when I play a movie. It’s not enough to make the audio out of sync with the video but it can affect the subtitles. If the audio is 20ms late in starting then a person will speak for an extra 20ms because of that thus the subtitle line goes away before you actually hear the last word finish so it feels like the subtitle line ended too early even though it didn’t and the audio is just late.
That wasn’t noticeable on the HP laptop because it’s a weak laptop but it’s noticeable on the Lenovo laptop because it’s more powerful.
Is what I said correct?