Python access to video frames (Carl Karsten)

[Marianna Smidth Buschle]

As suggested you can go some different ways:


- Make a python gst app:

filesrc ! decodebin ! appsink

opencv code

appsrc ! encode ! filesink

Passing the audio as well might be tricky...


- Make a python gst app:

filesrc ! demux name=demux1 ! decode ! identity ! encode ! mux name=mux1 
! filesink demux1. ! mux1

and use a probe to snatch frames at the identify element and do what you 
want there with opencv


- Make a filter element to do your stuff

filesrc ! demux name=demux1 ! decode ! filter ! encode ! mux name=mux1 ! 
filesink demux1. ! mux1


Best Regards

Marianna


On 13/10/2023 14.00, gstreamer-devel-request at lists.freedesktop.org wrote:
> I need to alter video frames, and Python is my happy place.
> my gst skills need some help.
>
> I think I need these 2 things:
>
> 1. pipeline:
> read a file,
> decode the video,
> hook? to read/write pixels,
> encode (keep the original audio)
> save to disk.
>
> 2. that hook code...
> I have done something before: use the wavelevel element to get audio
> data and generate static png images.
> https://github.com/CarlFK/veyepar/blob/master/dj/lib/gslevels.py#L72
>
> So I am assuming some element / message will give me a frame buffer
> thing of data, and somehow i can detect black pixels.
>
>
> End goal: fix some video;s I made of a live event where my setup
> introduced black squares - I want to replace the black with the pixels
> from the previous frame.
> example of what needs fixing:
> https://youtu.be/N5Anbq8vYNk?si=Gl89X3Uk5_2CrMu6&t=148
>
> The slide is mostly a static image, so the previous frame will be fine.
>
> -- Carl K

-- 
Best regards / Med venlig hilsen
“Marianna Smidth Buschle”