PNG compression

[Rturo]

Hi,

i'm using the NUCLEO U575ZI-Q board I want to compress some data I collect from analog sensors via png encoding in order to take advantage of compression, how can I do it? Are there special libraries for that?

I don't need to have the .png file but just encode the data with png encoding.

Thanks You.

[Tesla DeLorean]

I'm sure there a graphics library, commercially, or whatever, that provide PNG format support. Find something and port it to the platform.

[Pavel A.]

EmWin has .png support as extension (available from Segger, IIRC free). It should work for the ST emWin branch too. IIRC quite complicated, and pulls in some [de]compression code under unclear license. Of course, the decompression needs extra RAM and execution time.

[Rturo]

Thanks. It seems that STemWin is used when displays are present, I just need to encode the data in PNG format and then transmit it via LTE and I don't have a display. Also reading here https://www.st.com/en/embedded-software/stemwin.html it does not appear that the NUCLEO U575ZI-Q is supported. Can you confirm this for me? Are there any alternatives to encode data in PNG ?

[giustiziere_della_notte]

Eh grazie ar cazzo

 

[Pavel A.]

@Rturo So you need to create .png images on stm32?  On a rich host (PC, cloud) there are various libraries for converting images, even OpenCV

[Rturo]

Yes, I want to encode a png image on stm32, how can I do it?

[Pavel A.]

Hmm... port any existing tool to bare metal ARM32? This will take a bit of research.

[Pavel A.]

Actually the research here is very simple, can be summarized in one sentence. Segger can sell you everything you need, right now - but it will cost you (obviously).