Partial applying filter

[Jan Gruuthuse]

We now have a new feature in Avidemux 2.6.12 Filters: Partial
In this example we use the OpenGL Filter Shader Loader (also a recent addition) Lightning Effect example.
The Shader Loader is already loaded with Lightning Effect
- Right click in Active filters on the Shader Loader. (most used filters would be selectable)
- In dropdown popup select: Make Partial

[Jan Gruuthuse]

In Partial Filter edit the
- Start time (0:0:0,0)
- End time (0:0:0,960)
and press [OK]

[Jan Gruuthuse]

The filter will now show as Partial

small video demo: Partial Filter on our YouTube channel: Avidemux Demo

[Jan Gruuthuse]

Only with filters that :
* Dont change framerate
* Dont change size
* Dont need several frames (e.g. deinterlacer)

[p3trus]

Only with filters that :
* ..
* Dont need several frames (e.g. deinterlacer)

That's quite a bad change compared to the 2.5 branch - I process a lot of movies recorded on TV, and quite often those have 'sped up' end credits, having only those interlaced - now I have to deinterlace the whole video instead of only the last 1-2%.
Although it doesn't 'hurt' the non-interlaced part, it's unneccessary filter processing being applied to the huge main part of the video.

What's the technical difference between deinterlacing of the whole video from frame 0 to End (I don't have a frame -1 and End+1 there...) and processing only frame A (>0) to End?

[AQUAR]

Layman's explanation:

Avidemux doesn't know the order of the "virtual frames" in the video buffer.
And it doesn't know which other frames that "virtual frame A" depends on.

All that is handled internally by the video decoder used by Avidemux.
Avidemus operates on the next frame spit out by the video decoder (ie looks ahead by 1 frame only)

Hence why no smart copy and partial filers that need future frames or past frames decoding (ADM doesn't know how the fetch them).

The old ADM 2.5 branch kept track of all this frame ordering and frame referencing (hence why it was called a frame based video editor).
The new ADM branch 2.6 has given up this functionality in order to get along with current advanced codecs.
These advanced codecs have become very complex in this frame ordering and referencing.
I guess that's why ADM 2.6 is called a time based video editor and operates on sequentially/fully-decoded frames (relying on PTS and PAT to navigate).

Anyone:
This is just how I perceive the workings of ADM, based on the info gleaned in this forum
Feel free to provide a better/correct explanation.