JpegDec.decodeArray() always sets all the values to 0 on esp8266

[emilekm2142]

Serial.println(("===============")); Serial.println(("JPEG image info")); Serial.println(("===============")); Serial.print(("Width :")); Serial.println(JpegDec.width); Serial.print(("Height :")); Serial.println(JpegDec.height); Serial.print(("Components :")); Serial.println(JpegDec.comps); Serial.print(("MCU / row :")); Serial.println(JpegDec.MCUSPerRow); Serial.print(("MCU / col :")); Serial.println(JpegDec.MCUSPerCol); Serial.print(("Scan type :")); Serial.println(JpegDec.scanType); Serial.print(("MCU width :")); Serial.println(JpegDec.MCUWidth); Serial.print(("MCU height :")); Serial.println(JpegDec.MCUHeight); Serial.println(("==============="));

always show only zeros. I am sure that the array is a correct image. I use ESP8266 on Arduino 2.3.0 and can't update to 2.4.1 due to visualMicro plugin for visual studio and using Templates that work only with ms compiler. I read that it is a bug in Arduino Core, also there is a function drawRaw() that works, but I could not find it.

[Bodmer]

Does your array definition look like this: https://github.com/Bodmer/JPEGDecoder/blob/master/examples/MCUFRIEND_kbv/jpeg_kbv/jpeg1.h#L6

[emilekm2142]

The array you posted works :// Also, excuse me, I forgot to mention that the array is first decoded from base64.

std::vector<unsigned char> decodedData = base64_decode(img);
JpegDec.decodeArray(decodedData.data(), decodedData.size()); //decodedData.data() equivalent to &decodedData[0]

I am sure that base64_decode function gives a proper jpg. base64_decode -> https://pastebin.com/4S9rbNUB memchr.h -> https://pastebin.com/PBAM8NtP You will need a standardCplusPlus by Legacy library from the manager to run that. It works on a PC though.

[Bodmer]

I suspect this is an array format problem. The array is just a copy of the Jpeg file in a simple c coded byte array that is stored in program memory.

[Bodmer]

The function here is an example of how to create the array in c code format.

[opticron]

@emilekm2142 Something I encountered recently produced this kind of output as well. Make sure that when you export the JPEG that you disable progressive JPEGs since this library does not support it. It's a realtively easy setting to find in GIMP on the export dialog under advanced settings, so you can export it that way at the very least.

[Bodmer]

Thanks for the tip.