Can we check when an element's sink pad receives a buffer to add custom data to it
Hope someone can help me in the following :
1) How we can detect the arriving of buffers to an element's sink pad ?
If (1) is possible :
2) Can we add a callback to a function that indicating that sink pad has
received a buffer to do some modifications to this buffer or to add extra
custom data to it ?
If (1) isn't possible : when adding meta data to a buffer, is this extra
data will be processed by other elements or it will be transmitting from one
element to another without modifying ? (e.g. if i add a metadata to a buffer
pushed through my appsource, when an encoder element receives this buffers,
it will compress the metadata with the initial buffer ?)
Hope that I succeed to transmit what I need clearly !
You can change the data in the buffer as well, but someone else can probably
explain it better than I can;). W.r.t. metadata: AFAIK not all elements pass
metadata transparently (but that might have changed in 1.12/1.14).