[Bug] MPEG-4/DivX/Xvid videos stutter on Rock64

    Hello,

    I didn't find a thread about this problem, so I open one.

    Setup:

    • Rock64
    • LE nightly 20190506 for Rock64 (also tested on 8.90.014)
    • LE installed on eMMC

    Observation:

    • MPEG-4 (Layer 2) videos stutter
    • stutter is continuous throughout playback and multiple times per second (is it called jitter then?)
    • MPEG2/H264/H265 content plays flawlessly
    • resolution doesn't matter
    • whole kodi UI is sluggish with DivX content playing in the background (not otherwise)
    • video is a bit behind audio

    Tested:

    • CPU is around 50% (from 400% possible) for the usual SD content
    • PRIME on/off doesn't matter (probably not accelerated anyway)
    • deinterlacing on/off doesn't matter (material isn't interlaced anyway)
    • changed framerates (also to match source framerate) and the slower it gets the worse the stutter is even if it matches the source framerate

    Kind regards,

    ArchNMy

    Edited 5 times, last by ArchNMy (May 10, 2019 at 12:22 PM).

    had the same, also with h264 and h265. Did test different SD cards (which was suggested in here) und tested different buffering settings. None of it provided a solution. No matter if I play vom SD, USB, DLNA, SMB.


    I think buffering is the problem, because the grey buffering bar is jumping like a maniac, while it is very calm in other hardware/releases. Perhaps you can check that behavior on your device.

    flyingernst: The stutter is more of a consistent frame drop or jitter. On 25Hz it looks like I'm watching slow motion while not really being slower. Also H264 and H265 as well as MPEG2 content plays fine for me regardless of bitrate or resolution.

    LE is installed on eMMC and loads content from SMB, so it doesn't seem to be the same issue.

    Kwiboo: I suspected that it is software decoded, however the cpu usage doesn't exceed 70% (of 400%) so not even a single thread is completely used.

    The stutter is also continuous with no apparent spikes which leads me to think it has nothing to do with CPU performance limits. Also the stutter becomes way worse when setting the display refresh rate lower (for example 24Hz/25Hz which are the source frame rates for these cases).

    Deinterlacing turned off doesn't change the observed behavior.

    Do you have a Rock64 and if so do you see the same behavior on MPEG4/Xvid/DivX content?

    Edit: The jitter/framedrops/continuous stutter is also visible in the Kodi UI

    Edited once, last by ArchNMy (May 10, 2019 at 9:27 PM).

    Okay, I tested 720p H264 software decoding and it plays flawlessly while peaking at around 150% (while usually being around 110%). I think that should rule out a CPU bottleneck.

    Will traverse the logs if I see anything suspicious while playing back DivX/Xvid content.

    The log doesn't tell me much. I only found this:

    Code
    DEBUG: ActiveAE::SyncStream - average error of 16.908025, start adjusting
DEBUG: ActiveAE::SyncStream - average error 0.908025 below threshold of 30.000000
NOTICE: CDVDVideoCodecFFmpeg::CDropControl: calculated diff time: 40000
DEBUG: CDVDClock::ErrorAdjust - CVideoPlayerAudio::OutputPacket - error:-33362.743167, adjusted:-33362.743167

    However this also occurs in the smooth h264 playback test run.

    Regarding the logs, I removed video location and title from the log (with place holders) and removed spam from plugin.video.youtube and service.upnext as well as jsonrpc (from Kore app).

    It would even help if someone can replicate this observation on RK3328. Meaning: jittery playback on Xvid/DivX content and smooth playback on H264/AVC+H265/HEVC content

    It would also help if someone has smooth playback with Xvid/DivX content on RK3328 (Rock64 preferred of course :)).

    No you cannot disable gpu rendering (it is the only way to render sw decoded videos). Render sw decoded video using direct to plane is still work in progress.

    Possible due to a bug in Kodi, please test 8.90.015 and mainline image and see if problem is also present, they both have newer Kodi versions with important fixes.

    Nightly images is using the older 18.2rc1 version with some known bugs.

    LE master is still on that version because it is the latest taged version on kodi master branch.

    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.

    Quote from mike2002

    Just a little precision, my resolution is set to 720p. As soon I set it to 1080p suttering and jittering appear.

    Good point, any scaling will be done in GPU and the GPU in rk3328 is on the lower end. Changing scale mode in OSD -> Video settings may reduce stuttering and jittering.

    With the Direct-To-Plane renderer the video output processor (VOP) will do scaling and is not limited by the weaker GPU.

    This is the one of the reasons I want confirmation if this issue exists using mainline images.

    Quote from mike2002

    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.

    I do not think the CPU is the limiting factor, it is the GPU. I do not remember at what freq the GPU run on RK 4.4 images, it may be limited to 500 mhz. Previous testings showed that the GPU can be run at 600mhz without issues. Mainline images will run GPU at 500mhz.

    Kwiboo and mike2002: Thank you for clarification. Indeed changing resolution to 720p makes the playback of SD Xvid content smooth. I will test mainline build later on, just to see if it is there too or not.

    Also because of that explanation I tested SW decoding H264 SD content and indeed this stutters as well, so the scaling is the problem.

    I was really not aware that scaling is so computationally intensive. Also weird that changing to lower refresh rate really doesn't improve matters.

    Hi !

    I did a test with the mainline build. I confirm that the problem with the Divx and the Xvid are not present (1080p). And I test a HEVC video with success, the video is smooth and the quality is really good.

    Hello !

    after few more tests, forget this build for H265 HD but work well for H265 SD. Anyway, the future sound good for the Rock64 and other rockchips device under mainline kernel... But for the moment a lot more feature under kernel 4.4.