memory allocation failed

[simonchen007]

hello,

I'm using esp32 + lvgl + lv_lib_lodepng,
but when I use a png more 20K , it would shows "memory allocation failed", where can I change for making the memory allocation bigger ?

[embeddedt]

You probably have to increase LV_MEM_SIZE (or the size of whatever heap you use).

[simonchen007]

I change it as (64U * 1024U),still the same. however, I change it as 128U * 1024U , I would goes to compile error.

[kisvegabor]

lodepng uses normal malloc. So you are simply out of heap on ESP.

[simonchen007]

so, are you meaning the problem is because the esp32 having not enough money ?
I tested over 50 times last night, if the PNG is over 5kb, I would get this error.
however, if I use the normal way(make the png as c-array first), and do not use lodepng, 100kb png file is also works.

[kisvegabor]

so, are you meaning the problem is because the esp32 having not enough money ?

I don't know how much money ESP has but it might be out of memory. 🙂 :

The resolution of the PNG matters. During decoding the PNG image a hor. res x ver.res. x color size array is allocated into RAM. E.g. for 200 px x 200 px x 2 bytes = ~80kB

[simonchen007]

esp32 having 320K memory.
And I read the code of lodepng, "memory allocation failed" is because case 83 . if esp32 out of memory, I would not send any error, it would just go reboot.

[kisvegabor]

What is the resolution of the image?

[simonchen007]

320*480

[kisvegabor]

It means the decompressed image is 3202402 = 300kB. If it uses 32-bit color format internally (I'm not sure now) than its 600 kB. Anyway, 320kB is not enough in either case.

[simonchen007]

but why if I use the normal way(make the png as c-array first), and do not use lodepng, even 100kb png file is works ?

[embeddedt]

The PNG doesn't need to be decoded into RAM first with that method. It can be drawn directly from flash to the display.

[rambo-panda]

I also encountered the problem under lvgl 8.3. But I found two ways to solve it

1. #LV_MEM_CUSTOM 1 use the malloc and free realloc
2. convert to *.bin file

waiting for the real solution 😄

[kisvegabor]

You can increase LV_MEM_SIZE to add more memory for LVGL.

[rambo-panda]

Yes I tried, but it still reports an error。 So I personally think it's possible that lvgl's heap management may not be able to allocate large chunks of memory due to memory fragmentation in some cases