AviSynth behaviour dependent on application

[vijays]

Dear all,
I wanted to know if Avisynth behaviour varies from application to application. To make it clear, let me explain you the scenario:

I have two applications, say X and Y that take a .avs file as input. Let us say the Avisynth script is supposed to convert .wmv file to frames of RGB32. Now if the same avs file input to both X and Y, is it possible (even remotely) that they receive different set of frames? Different frames could mean:
i. DIfferent total number of RGB32 frames produced for same wmv file (Ex: X receives 100, Y receives 101)
ii. Same number of RGB32 frames but wmv file was sampled at different points hence resulting in 2 slightly shifted versions

Thank you in advance.
Vijay

[Guest]

Yes, it is possible. For example, if the source filter in the script does not do random access fully correctly, then depending upon how the applications issue their requests for frames, the returned frames may differ.

[Gavino]

if the source filter in the script does not do random access fully correctly, then depending upon how the applications issue their requests for frames, the returned frames may differ.
Just to clarify, I assume you are you saying that such a source filter is broken?
In other words, this behaviour would be a bug, not a feature.
Or could it be acceptable for some formats?

[Guest]

It just means that the filter doesn't support frame accurate seeking. It's only a bug if the filter implements it and it doesn't work right. But if the filter doesn't even claim to support it, then formally, it's not a bug. :)

For DirectShowSource() it works right for some stream types and not for others. Is that a bug? You decide.

[stickboy]

I think different applications can report errors differently too.

[Comatose]

AvsP starts giving python errors endlessly (requiring you to kill the process) when ffmpegsource says it cannot do frame accurate seeking in this stream, while Virtualdub just reports an error :p

[TheFluff]

ffmpegsource says it cannot do frame accurate seeking in this stream

try seekmode=2, it may or may not be frameaccurate

[vijays]

Thank you for the responses! It was really helpful to interpret my results.