SG-40625 - Play Forward/Pause button stops responding when playing media files (Linux)

[cedrik-fuoco-adsk]

SG-40625 - Play Forward/Pause button stops responding when playing media files (Linux)

Linked issues

n/a

Summarize your change.

Describe the reason for the change.

There was a stability problem where calling stop() or reset() on the QAudioOutput object would cause audio playback to break after multiple play/stop cycles. To work around this, suspend() was used instead, which solved the instability. However, this introduced a second problem: suspend() does not clear the audio device's internal buffer. This resulted in an audio bleed issue, where sound from the previously played media could be heard for a fraction of a second when starting a new one.

Describe what you have tested and on which operating system.

This change introduces a new flushing mechanism that resolves the audio bleed on Linux while avoiding the unstable stop() and reset() calls.

When playback is stopped, instead of immediately suspending the audio device, a new flushing process is initiated. The audio device is kept active momentarily while it is fed with silent audio data, completely overwriting the contents of its internal buffer. Once the buffer is flushed, the device is safely suspended.

This ensures that the audio buffer is clear before the next playback begins, eliminating audio bleed. Because this approach continues to use suspend() to halt the device, it maintains the stability of the audio system.

This logic is confined to the Linux platform and does not affect the behavior on MacOS or Windows.

Add a list of changes, and note any that might need special attention during the review.

If possible, provide screenshots.

[bernie-laberge]

LGTM
Please make sure to ask QA to do lots of audio testing on Linux (since it is the only affected platform in this commit)

[pbergeron-adsk]

LGTM, and whoa nice find.