Camera High Speed Mode can't reach the target fps, and can't set auto focus only once

_Please read the [prerequisites] to run scrcpy._

[prerequisites]: https://github.com/Genymobile/scrcpy#prerequisites

_Also read the [FAQ] and check if your [issue][issues] already exists._

[FAQ]: https://github.com/Genymobile/scrcpy/blob/master/FAQ.md
[issues]: https://github.com/Genymobile/scrcpy/issues

## Environment

- **OS:** Windows
- **Scrcpy version:**scrcpy-win64-v3.3.3
- **Installation method:** just download release package, and unzip , then run scrcpy.exe in terminal
- **Device model:** OPPO A5 5G(Qualcom Snapdragon 685), Onplus 12(Qualcom Snapdragon8 Gen3)
- **Android version:** Android 16

## Describe the bug

I need use camera high speed to record another phone screen at max 120 fps

I run --list-camera-size

High speed capture (--camera-high-speed) (A5 5G):
--camera-id=0
- 1280x720 (fps=[120, 240])
- 720x480 (fps=[120, 240])
- 640x480 (fps=[120, 240])
- 1920x1080 (fps=[120, 240])

High speed capture (--camera-high-speed) (Oneplus 12):
--camera-id=0
- 1280x720 (fps=[120, 240, 480])
- 720x480 (fps=[120, 240, 480])
- 640x480 (fps=[120, 240, 480])
- 1920x1080 (fps=[120, 240, 480])

I have tried 1920x1080 , 1280x720, 720x480, 640x480 at 120fps by the following command:

scrcpy.exe --video-source=camera --camera-id=0 --camera-high-speed --camera-size= --camera-fps=120 -r output.mp4

by looking the attribute of video file, the result is the following:
the test result is following (OPPO A5 5G):
1920x180 at 95.98 fps
1280x720 at 104.11 fps
720x480 at 117.96 fps
640x480 at 116.92 fps

the test result is following (Oneplus 12):
1920x180 at 59.42 fps
1280x720 at 59.37 fps
720x480 at 58.93 fps
640x480 at 59.69 fps

It looks like scrcpy can't reach 120fps at high resolution, how do debug that?

Another question is , I want to record the screen of mobile phone, however the change of screen content will trigger the re-focusing, however I don't want trigger re-focusing ,that will affect my performance test based on the video. could you fix that? offer a only auto focus once option.

```
Please paste terminal output in a code block.
```

Please do not post screenshots of your terminal, just post the content as text instead.

Reproduce the reported commands using --video-source=camera, --camera-high-speed, --camera-size, and --camera-fps=120 on the listed devices, then inspect the recorded video metadata. Trace the camera high-speed and autofocus handling from those command-line entry points. Done means explaining or correcting the frame-rate discrepancy and providing a way to autofocus only once.

Written by the indexing model from the issue text.