I had guessed the output format can also simply be changed by writing to the ov2640 register. At least it says it on the main page, that the other settings would be available.

Anyways, I am fine with working with jpg, but unfortunately I cannot reproduce the jpeg yet in an RGBA8 texture with the given resolution from the provided buffer (~8000 bytes). The photo taken is just white/grey.

I am just sending the uint8_t buffer over Serial
for (uint32_t i = 0; i<frame.size; i++) { Serial.write( frame.buf[i] ); }, and read the bytes to a texture, while filtering for Jpeg Start ff d8 and Stops ff d9 (which I find).

The length / size of the buffer ~1000-3000 for the 160x140 resolution, seems suspiciously low though, compared to the relatively good image shown on the Core2 display. Hm.. I assume the buffer has to be uncompressed based on compression settings found in the Jpeg header bytes..

-- Got it working by decompressing jpeg

I've extended the Cam2Core example to show how to send commands to the camera. You can find it here.

The API allows to change many settings, including resolution and quality. However I don't think it includes a way to switch the encoding. JPEG seems to be hardcoded into the camera firmware.

Thanks
Felix

I just found the device control register list for the ov2640. But I have to figure out how to write to the registers via Core2/ESP32

The older esp_camera.h is getting camera addresses and configs from sensor.h (OV2640 is on 0x26 there)