there is no change
@Stef_Weicks so that is really the recording that fails. I still don’t get the half frame part. I need sometime to look at that.
At least now we know that it´s the recording part 
@Stef_Weicks hello I see that the size of your file savedata_5000.dat is 124.5Kb do you have the same ?
@Yves_BAZIN no?! mine is 31,3 MB !
i locked at my cloud… its also 31,3 MB
could you try again … downloading the file?
@Stef_Weicks the file should be more like 36MB
50008030*3/1024/1024=36.6 MB
It’s like indeed part of it has not be recorded.
ah … ok i understand…
do you have any idea of how this can happen?
@Stef_Weicks couple in my mind I will make couple of changes in my new artnet lib and send you a new version.
ok great!
… do you know, it must be possible to save *.dat files to the ESP without needing a SD-card? its not really important but good to know. so you could save a sdcard 
@Stef_Weicks yes to the spiff memory but you do not have more than couple MB.
oh yes you are right… i didnt think of the size! 
@Stef_Weicks
new Artnet
new save program
i have increased the size of the buffer to 10
look at the serial output to see if all the buffer have been created from 0 to 9
if not all of them can be created just reduce to 9
i testet it , but now the jerks make much bigger jumps… ?
i tried it with buffer 10 and 9 and also with
xTaskCreatePinnedToCore(FastLEDshowTask2, “FastLEDshowTask2”, 3000, NULL,3, &FastLEDshowTaskHandle2, FASTLED_SHOW_CORE);
and
xTaskCreatePinnedToCore(FastLEDshowTask2, “FastLEDshowTask2”, 1000, NULL,3, &FastLEDshowTaskHandle2, FASTLED_SHOW_CORE);
there is not much difference
@Stef_Weicks can you show me the video.
and sometimes all panels are white for a few milisec. often at the beginning if i switch on the controller
@Stef_Weicks what is the size of the file ? How many frames ? Did you record
7,32 Mb 1000 frames