Auto-cropping of slides source

[fightling]

For example by using videocrop and videoanalyse gstreamer elements in combination voc2mix could easily detect 4:3 slides or centered pictures that could be enlarged by cropping and presenting them in a lecture composite.

[danimo]

Is there any way to detect 4:3 slides that have been stretched to 16:9 (e.g. by certain scalers)?

[fightling]

Is there any way to detect 4:3 slides that have been stretched to 16:9 (e.g. by certain scalers)?

don't think so