Avisynth 3.5 vs 3.6+

[chainikdn]

Right now we're building with the latest AVS 3.6 headers. This resulting in AVSF is not working with AVS 3.5 installed solely due to AVISYNTH_INTERFACE_VERSION was bumped from 6 to 8. The filter doesn't depend on anything specific to the updated interface.

We (SVP) now have a problem: ffdshow doesn't work with AVS 3.6+ (https://github.com/AviSynth/AviSynthPlus/issues/178) and AVSF doesn't work with AVS 3.5.

So, may I suggest building AVSF with headers from 3.5.0 release? Again, I don't see any difference for AVSF now.

[CrendKing]

I could. What's you guys' long term plan? Staying on 3.5 forever, since ffdshow is unlikely to update anymore, or only temporary?

[chainikdn]

Long term - forget about ffdshow, I hope. step 1: ffdshow is still the default "engine" with AVSF installed alongside step 2: AVSF is default, ffdshow remains for compatibility step 3: AVSF only

[CrendKing]

I'll build with 3.5 next version.

[chainikdn]

0.7.5 - "Only a single prefetcher..." on AVS 3.5 when switching an audio track (MPC-HC, PotPlayer)

[CrendKing]

I went to destroy the whole IScriptEnvironment and unload the dll, stop all worker threads, then reload them back. The crash is still there. I don't know what persisted through the process.

[CrendKing]

@chainikdn I think I know why there's problem with the new filter version and tracking switching.

As I understand, the C++ interface of AviSynthPlus basically assumes there will be only one IScriptEnvironment. I say this because AVS_linkage is a global variable, and it is linked to the avs environment. So naturally I initialize it at the beginning of all logic and never touches it again.

When the player first loads the filter, it put it into the filter graph and hold a reference. The filter graph lives until the player shuts down. Here is the problem: when you switch a track, it instructs the filter to flush and release everything, via Inactive(). However, it never release the filter itself. Then it creates another instance of the filter, add to filter graph, and use the new instance from then on. Both instances get released with the graph at player shutdown. At this time, we have inconsistency: all filter logic uses states from the new instance, but all AVS cache still references to the old instance.

Obviously, there are ways to workaround:

1. Make the filter a singleton. This should theocratically fix the problem, but the doc specifically says CreateInstance() should create new instance.
2. Release filter at Inactive(). It works but I don't know if this would create new problem, as the reference count are wrong now.
3. Delete avs environment at Inactive() and recreate new environment. Seems to be the cleanest solution, but because the old filter still need refers to the old AVS_linkage, when destroying the old filter undefined behavior could happen.

I don't know why does the filter graph not release filters when switching track. It could also be a bug in my code, like I forgot to release in a function.

[chainikdn]

... just wanted to mention that it starts to work after seeking. play -> switch tracks -> error -> seek -> ok

[CrendKing]

I fixed something in https://github.com/CrendKing/avisynth_filter/issues/18#issuecomment-719144423. Try it.

[chainikdn]

Ok, I just returned from a holiday trip... installed 0.8.0, and it now hangs when switching tracks regardless the Avisynth version used.

[CrendKing]

Oops, I miscounted this use case after fixing another bug. Sorry there were several issues at hand at the end of v.0.7.x line. It's like those "leaking bucket" rhetoric: filling up one hole opens another 😃.

Try AviSynthFilter.zip. Also try other cases, in case another hole is open.

[chainikdn]

thanks, looks much better