VLC playback mechanics

[Melanchall]

Hello,

I'm interested in how VLC plays data. From what I've read in the sources and Wiki my assumption is VLC uses kind of timer/clock or loop with sleep between frames. But what exactly drives playback?

For example, in C files regarding Windows I see call timeBeginPeriod(5) which means setting system timer interval to 5 ms. Can you please explain why? To have a timer to draw frames on each tick if needed? Or to change resolution of sleep during infinite loop which draws frames?

Thanks in advance

[Rémi Denis-Courmont]

Timing is specified by the source media.

[Melanchall]

Timing is specified by the source media.

Can you please explain this? Let's imagine a simple picture: a video that is a set of images with 24fps. How VLC will show this video? I mean, how VLC respects timing between frames (1/24 s)? It's driven by timer or VLC sends graphics buffers to videocard directly waiting for callbacks from it?

[unidan]

VLC 3.0 currently compare the media time against a media clock whose parameters are generated from the media timing information. When the clock says that the media time associated with a frame has been reached, it renders the frame. So in a sense, it's "like" timers yes, and not tickless or event-driven.

[Melanchall]

VLC 3.0 currently compare the media time against a media clock whose parameters are generated from the media timing information. When the clock says that the media time associated with a frame has been reached, it renders the frame. So in a sense, it's "like" timers yes, and not tickless or event-driven.

Thank you very much for reply!