[BUG]: Video Playback from ISO has frame time spikes, but not from CHDs.

[JWatersMeet]

Describe the Bug

When running a game which streams video off the DVD image, using an ISO image results in frame time spikes. I have seen this in all of the Taiko games, and also Persona 4 and Lucky Star. I haven't tested others. Compressing the same game ISO to a CHD and running the CHD instead results in the video playing back normally, without frame time spikes.

These spikes are significant enough to disrupt smooth video playback, though it's hard to see in the screen captures below - look at the frame times in the top right.

Taiko 1, from an ISO: https://github.com/PCSX2/pcsx2/assets/136824455/5d2e9a6e-7954-4bca-a9fb-63abf943d8a9

Taiko 1, from a CHD: https://github.com/PCSX2/pcsx2/assets/136824455/6a09c845-dac4-40aa-a1af-54eb51996b3c

Reproduction Steps

1. Enable frame times OSD option.
2. Start game from ISO, wait for intro video to play, note janky playback / frametime spikes.
3. End Game
4. Compress same game to CHD (chdman.exe createcd -i game.iso -o game.chd)
5. Start game from CHD, wait for intro video to play, note smooth playback.

Expected Behavior

Video playback from ISO images should be smooth.

PCSX2 Revision

1.7.5793

Operating System

Windows 11

If Linux - Specify Distro

No response

Logs & Dumps

No response

[stenzek]

Give #11258 a try, it uses the threaded reader instead of AIO.

If you're running from a network path or something to begin with though, it could be problematic.

[JWatersMeet]

That fixes it, many thanks!