Runtime variables scope and lifetime

[StainlessS]

As linked in #post 16 by Gavino

Originally Posted by Gavino

Yes, the string table does accumulate entries for each frame rendered by a run-time filter.
I can think of a number of ways this could be improved/fixed, including changes to ScriptClip itself, but normally there is a simple workaround - use functions to cut down the size of the run-time script. Taking this approach to its limit, you can even replace the entire run-time script by a function call. Instead of writing

ScriptClip("""
  ... # very long script
""")

do this

function f(clip c, int current_frame) {
  c
  ... # code from run-time script
}
...
ScriptClip("f(current_frame)")

See here for an example which fixed a previously mysterious memory leak in SRestore.
(BTW The current_frame parameter is not needed if using GRunT, since it makes current_frame global).

In your case, the recursive use of ScriptClip adds a further complication, but I think you could restructure your code to call ScriptClip once and do the recursion inside it. In fact, you said in post #4 that you were able to do this with your earlier code.

So would not need to be, it is Grunt that does the clever stuff there.
In your other thread I think I passed current_frame in at least one snippet that did not need an explicit current_frame (If Grunt is installed).

[fvisagie]

I was confusing GScript and GRunT, thanks!

[StainlessS]

Yep, I do that myself all of the time, perhaps a single plug called eg GruntScript() is called for.

[fvisagie]

Originally Posted by Gavino

As StainlessS says, the string argument to ScriptClip() is instantiated once only, when the outer script is parsed.

However, at run-time, that string is itself parsed afresh by ScriptClip() for every frame, each time using up space in Avisynth's string table for variable names, etc.

Somewhat naïve testing seems to indicate that this applies equally much to FrameEvaluate() as might be expected; does the theory agree?

scriptclip.avs

fps = 25.0
BlankClip(length=Int(3600*fps), fps=fps)
evens = 0
ScriptClip("""
    evens = current_frame / 2 * 2 == current_frame \
        ? evens + 1 \
        : evens
    last
""", show=false, after_frame=false)

scriptclip2.avs

fps = 25.0
BlankClip(length=2*Int(3600*fps), fps=fps)
evens = 0
ScriptClip("""
    evens = current_frame / 2 * 2 == current_frame \
        ? evens + 1 \
        : evens
    last
""", show=false, after_frame=false)

frameevaluate.avs

fps = 25.0
BlankClip(length=Int(3600*fps), fps=fps)
evens = 0
FrameEvaluate("""
    evens = current_frame / 2 * 2 == current_frame \
        ? evens + 1 \
        : evens
#   last
""", show=false, after_frame=false)

frameevaluate2.avs

fps = 25.0
BlankClip(length=2*Int(3600*fps), fps=fps)
evens = 0
FrameEvaluate("""
    evens = current_frame / 2 * 2 == current_frame \
        ? evens + 1 \
        : evens
#   last
""", show=false, after_frame=false)

>avsmeter scriptclip.avs

AVSMeter 1.7.9 (AVS 2.6, x86) by Groucho2004
AviSynth 2.60, build:Jan 14 2013 [16:50:35]

Number of frames: 90000
Length (hhh:mm:ss.ms): 001:00:00.000
Frame width: 640
Frame height: 480
Framerate: 25.000 (25/1)
Colorspace: RGB32

Frames processed: 90000 (0 - 89999)
FPS (min | max | average): 66717 | 97485 | 91832
CPU usage (average): 23%
Thread count: 1
Physical Memory usage (peak): 15 MB
Virtual Memory usage (peak): 12 MB
Time (elapsed): 000:00:00.980

>avsmeter scriptclip2.avs

AVSMeter 1.7.9 (AVS 2.6, x86) by Groucho2004
AviSynth 2.60, build:Jan 14 2013 [16:50:35]

Number of frames: 180000
Length (hhh:mm:ss.ms): 002:00:00.000
Frame width: 640
Frame height: 480
Framerate: 25.000 (25/1)
Colorspace: RGB32

Frames processed: 180000 (0 - 179999)
FPS (min | max | average): 69540 | 97453 | 92068
CPU usage (average): 24%
Thread count: 1
Physical Memory usage (peak): 20 MB
Virtual Memory usage (peak): 18 MB
Time (elapsed): 000:00:01.955

>avsmeter frameevaluate.avs

AVSMeter 1.7.9 (AVS 2.6, x86) by Groucho2004
AviSynth 2.60, build:Jan 14 2013 [16:50:35]

Number of frames: 90000
Length (hhh:mm:ss.ms): 001:00:00.000
Frame width: 640
Frame height: 480
Framerate: 25.000 (25/1)
Colorspace: RGB32

Frames processed: 90000 (0 - 89999)
FPS (min | max | average): 94501 | 115677 | 110254
CPU usage (average): 22%
Thread count: 1
Physical Memory usage (peak): 14 MB
Virtual Memory usage (peak): 12 MB
Time (elapsed): 000:00:00.816

>avsmeter frameevaluate2.avs

AVSMeter 1.7.9 (AVS 2.6, x86) by Groucho2004
AviSynth 2.60, build:Jan 14 2013 [16:50:35]

Number of frames: 180000
Length (hhh:mm:ss.ms): 002:00:00.000
Frame width: 640
Frame height: 480
Framerate: 25.000 (25/1)
Colorspace: RGB32

Frames processed: 180000 (0 - 179999)
FPS (min | max | average): 96123 | 114681 | 110382
CPU usage (average): 23%
Thread count: 1
Physical Memory usage (peak): 19 MB
Virtual Memory usage (peak): 17 MB
Time (elapsed): 000:00:01.631

[Gavino]

Originally Posted by fvisagie

Somewhat naïve testing seems to indicate that this applies equally much to FrameEvaluate() as might be expected; does the theory agree?

Yes. All the run-time filters (ScriptClip(), FrameEvaluate(), ConditionalFilter(), WriteFile[If]()) basically work the same way as far as string parsing is concerned.

[fvisagie]

Thanks.