DirectShow filter to queue samples and pass them downstream when needed

Question

I am writing a custom filter that helps in buffering samples (the number of buffered samples can vary depending on the resolution of recorded video) then do some modifications on these samples, later pass these samples to downstream filters.

Is there any directshow filter that my custom filter can derive from, to achieve this?

Currently i have my custom filter derived from CTransformFilter, but i am not sure how to pass the buffered frames downstream only when an event occurs.

Answer 1

There is some directshow filter samples. As far as CTransformFilter concerned, If the filter should not deliver this sample (for example, to support quality control), the method should return S_FALSE.
Introduction to DirectShow Filter Development document attached.