Hi !
I did a quick test with my Rock64 with Libreelec 8.90.015. I play a DivX without problem, no stutter/Jitter. I play it 5 minutes without any glitch. I previously played a lot of H264 and h265 contents without issue.
Just a little precision, my resolution is set to 720p. As soon I set it to 1080p suttering and jittering appear.
No stutter/jitter at 720p but that appear at 1080p with this video
Video
ID : 0
Format : MPEG-4 Visual
Codec ID : DIV3
Codec ID/Hint : DivX 3 Low
Duration : 1 h 57 min
Bit rate : 694 kb/s
Width : 576 pixels
Height : 432 pixels
Display aspect ratio : 4:3
Frame rate : 25.000 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.112
Stream size : 585 MiB (83%)
Samething for this one :
Video
ID : 0
Format : MPEG-4 Visual
Format profile : Advanced Simple@L5
Format settings : BVOP2
Format settings, BVOP : 2
Format settings, QPel : No
Format settings, GMC : No warppoints
Format settings, Matrix : Default (MPEG)
Muxing mode : Packed bitstream
Codec ID : XVID
Codec ID/Hint : XviD
Duration : 40 min 35 s
Bit rate : 1 060 kb/s
Width : 720 pixels
Height : 404 pixels
Display aspect ratio : 16:9
Frame rate : 25.000 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.146
Stream size : 308 MiB (88%)
Writing library : XviD 64
Personnaly I think it's more related to horsepower, I play the exact same contents in 1080p without glitch with my Rockpi4. Actually the Rock64 is clock at 1.2 Ghz, if we can clock it at 1.5 Ghz (like armbian do with the Rock64) maybe that can help to eliminate the stuttering.