System Information
Widows 8.0 Intel HD 4600
Blender Version
Broken: 2.72b
Short description of error
This may be a windows or windows 8x problem
Exact steps for others to reproduce the error
In the video sequencer the video plays at the correct frame frame rate however when the window is opened the frame rate drops to about 2 fps
My .blend for testing
Think this is normal and can be expected. If the window is open, the whole UI has to be drawn and the usual handling is done. I'd consider this as the root of the issue... @Campbell Barton (campbellbarton), @Bastien Montagne (mont29), do you agree here?
Assuming the window means the sequencer preview window?
In this case, then yes, this is to be expected - if the video editor is having to calculate effects, it will slow down playback until its cached.
Note that we're aware this sequencer could be optimized, but it doesn't really have an active maintainer,
Even so - this may be a TODO for gooseberry since its one of the requests from the team.
@Campbell Barton (campbellbarton) Yes the widow is the sequencer window. But it is never cached it will play through multiple times without caching. Also it will play at normal frame rate for about 2 seconds before returning to its 3 fps
it does not cache even if i plays through but if a play it at 1/4 the resolution it is cached and plays smooth.
I think it is a bug with the caching system.
yeah, but I'm afraid 1080p is too much for our poor sequencer :/ That would mean it is cached, but our Blender is not able to render the frames fast enough to display at full frame rate.
If you want us to double check or if you don't believe me in this you can upload the video somewhere and I'll test it ;)