FEL - Amlogic NO support

Portisch · 6 July 2026 07:33

Ejz · 6 July 2026 10:33

Why don’t you just stop the video and then start it again? Seems easier than having to rewind multiple times. That’s what I do when it goes out of sync.

I didn’t realize it might be because of pause/rewind that triggers it.

Portisch · 6 July 2026 10:57

github.com/xbmc/xbmc

[VideoPlayer][AudioEngine] Add opt-in LAV Audio passthrough A/V sync

master ← SamuriHL:lav-audio-passthrough-sync

opened 03:20PM - 05 Jul 26 UTC

SamuriHL

+1042 -48

## Description Adds an **opt-in** passthrough audio synchronisation mode — **"L…AV Audio"** (`audiooutput.lavsync`, default **off**) — for bitstreamed **TrueHD, DTS and Dolby Digital** output. It is available under *System → Audio* and enabled only when `audiooutput.passthrough` is on. ## Motivation / Problem For passthrough (bitstreamed) audio, Kodi forwards demuxer timestamps directly and **cannot resample** to correct timing. Two problems follow: - **TrueHD seamless branch points** (e.g. the clip joins in Blu-ray/UHD playlists, which restart the MAT frame timing) are only handled by the stock MAT packer's coarse *"padding overflow → wipe state → skip until next major sync"* path. That either **drops audio** or shifts the MAT audio-unit boundaries, which strict TrueHD decoders can lose lock on. - **Passthrough A/V timing jitter and drift** can't be corrected by resampling, so it accumulates or forces audible whole-frame skips/duplications. ## Solution / Design When enabled, the passthrough codec runs an **internal clock** synced to VideoPlayer's coordinated `GENERAL_RESYNC` timestamp, and **continuously corrects any timing jitter/drift** against the demuxer PTS whenever it exceeds a per-codec threshold. This runs **every frame** — it corrects ongoing drift as well as the large sudden jumps at seamless branch points, and is *not* limited to branch points. For TrueHD, the MAT packer additionally gains `outputTiming`-based discontinuity detection with **padding carry-forward**, so branch points no longer drop frames. Key properties for review: - **Entirely gated** behind `audiooutput.lavsync` (default off). With the setting off, every code path is identical to current behaviour — the MAT packer, the passthrough PTS handling and the player all take their existing stock paths. - The MAT packer's `outputTiming` substrate is re-added **additively and gated**, not by reverting the existing simplification — so there is **no baseline regression**. - **Scope is passthrough only.** Decoded/PCM audio is unchanged. - New jitter tracker `CFloatingAverage` (min-abs correction) is a small header-only utility. ### Files - `cores/AudioEngine/Utils/PackerMAT.{h,cpp}` — gated TrueHD seamless-branch handling. - `cores/VideoPlayer/DVDCodecs/Audio/DVDAudioCodecPassthrough.{h,cpp}` — internal-clock + jitter sync. - `cores/VideoPlayer/DVDCodecs/Audio/FloatingAverage.h` — new jitter tracker. - `cores/VideoPlayer/DVDCodecs/Audio/DVDAudioCodec.h` — two inert `DVDAudioFrame` discontinuity fields. - `cores/VideoPlayer/VideoPlayerAudio.{h,cpp}` — enable on the passthrough codec + rebase its clock on RESYNC. - `settings/Settings.h`, `system/settings/settings.xml`, `addons/resource.language.en_gb/.../strings.po` — the new setting + strings. ## Credit The passthrough A/V sync model (internal clock + `FloatingAverage` min-abs jitter correction) and the TrueHD MAT seamless-branch handling are **derived from [LAV Filters](https://github.com/Nevcairiel/LAVFilters) by Hendrik Leppkes (Nevcairiel)**. **Full credit for the LAV Audio design belongs to him** — this PR is an adaptation of that work to Kodi's passthrough pipeline. The derivation is attributed in the relevant file headers and the setting description. ## Testing - Builds and links cleanly against current `master` (x11 / GL, GCC 13, internal ffmpeg/fmt/spdlog/etc.); `clang-format` clean on the changed lines. - With the setting **off**, behaviour is byte-identical to stock (all LAV paths gated). - The underlying sync model has been in field use in downstream CoreELEC/Amlogic builds; on-device passthrough testing (TrueHD/DTS/DD, seamless-branch discs, seek-to-resume) on upstream builds is welcome from anyone able to bitstream. 🤖 Generated with [Claude Code](https://claude.com/claude-code)

The main problem I see is that stock Kodi does not support Dolby Vision, especially dual layer P7 FEL. This is CoreELEC fork only.

Also a fact is that most of TK does not even own a HDR screen…

I will try this PR if there are improvements or not and pick if it does.

SamuriHL · 6 July 2026 13:26

Thanks for looking. Just to clarify scope: this PR is audio-only — it changes the TrueHD MAT packer and the passthrough audio clock/jitter handling. It doesn’t touch the video pipeline or Dolby Vision in any way.

The trigger it addresses, TrueHD seamless branching, is a Blu-ray/UHD playlist structure (multi-clip titles restart the TrueHD outputTiming counter at clip joins), which is independent of DV. It occurs on standard Blu-rays, non-DV UHDs, and DV titles played as their HDR10 base layer — all of which stock Kodi plays via libbluray. So you don’t need DV (or the CoreELEC fork) to hit either the seamless-branch dropout or the passthrough A/V drift this fixes; DV support isn’t a prerequisite.

The whole feature is gated behind audiooutput.lavsync (default off), so there’s no change to existing behaviour unless a user opts in. Happy to expand on any specific case — were you thinking of a particular disc/demux path where DV would affect the audio timing?

bluesea · 6 July 2026 13:43

Portisch · 6 July 2026 13:44

All users report TrueHD audio sync issues when using unofficial forks/frankenstein builds by playing Dolby Vision (DV) content, and only the LAV Filters fix it for them.
It’s all about libbluray + ISO and illegal shared media content.

DV is the most popular format used with TrueHD and is also the most complex, especially Profile 7 (P7) FEL dual-layer content.

On official CoreELEC CE-NO 22 there are no such issues. I only know a issue when played a P7 FEL/TrueHD sample I need to reset the TV audio device to get back in sync. Maybe this change will fix this item.

SamuriHL · 6 July 2026 13:48

The Martian is another seamless branch title with no DV that drops audio for me in stock Kodi when using passthrough audio. The LAV Audio code I ported fixes it there, as well.

Ejz · 6 July 2026 15:06

I got a kernel panic after reboot, not a normal Kodi crash. pstore shows stack-protector: Kernel stack is corrupted in: Commit2DmKs+0xd10/0xd14 [dovi_gen_5_15_2026], followed by Kernel panic - not syncing: BRK handler: Fatal exception in interrupt. The call trace goes through Commit2DmKs -> commit_reg -> multi_control_path -> amdolby_vision_process, and boot also logs dovi_gen_5_15_2026: disagrees about version of symbol module_layout / __stack_chk_fail with please rebuild ko.

Using latest nightly on AM9 Pro with 5.15_2.6_dovi_patched_fix_fel.ko

kernel-panic-pstore:

dmesg

Kodi logs shows nothing. Last entry before the restart was 15 min before the crash.

2026-07-06 16:13:51.961 T:5821     info <general>: VideoInfoScanner: Finished scan. Scanning for video info took 8 ms
2026-07-06 16:13:52.008 T:1504     info <general>: JELLYFIN.jellyfin_kodi.monitor -> INFO::jellyfin_kodi/monitor.py:58 -->[ kodi scan/video ]
2026-07-06 16:13:52.017 T:1504     info <general>: JELLYFIN.jellyfin_kodi.monitor -> INFO::jellyfin_kodi/monitor.py:61 --<[ kodi scan/video ]
2026-07-06 16:14:36.848 T:5831  warning <general>: CPythonInvoker(17): Script invoked without an addon. Adding all addon modules installed to python path as fallback. This behaviour will be removed in future version.

and then

2026-07-06 16:30:41.159 T:1421     info <general>: Starting Kodi (22.0-BETA1 (21.90.801) Git:f37663947cb2440176697d5e496c9260a235947f). Platform: Linux ARM 64-bit
2026-07-06 16:30:41.159 T:1421     info <general>: Using Release Kodi x64
2026-07-06 16:30:41.159 T:1421     info <general>: Kodi compiled 2026-07-06 02:15:23 by GCC 16.1.0 for Linux ARM 64-bit version 5.15.196 (331716)
2026-07-06 16:30:41.159 T:1421     info <general>: Running on Ugoos AM9 Pro with CoreELEC (official): 22.0-Piers_nightly_20260706, kernel: Linux ARM 64-bit version 5.15.196
2026-07-06 16:30:41.159 T:1421     info <general>: FFmpeg version/source: 8.1.2
2026-07-06 16:30:41.159 T:1421     info <general>: 4 CPU cores available
2026-07-06 16:30:41.159 T:1421     info <general>: ARM Features: Neon enabled
2026-07-06 16:30:41.159 T:1421     info <general>: special://xbmc/ is mapped to: /usr/share/kodi/
2026-07-06 16:30:41.159 T:1421     info <general>: special://xbmcbin/ is mapped to: /usr/lib/kodi
2026-07-06 16:30:41.159 T:1421     info <general>: special://xbmcbinaddons/ is mapped to: /usr/lib/kodi/addons
2026-07-06 16:30:41.159 T:1421     info <general>: special://masterprofile/ is mapped to: /storage/.kodi/userdata
2026-07-06 16:30:41.159 T:1421     info <general>: special://envhome/ is mapped to: /storage
2026-07-06 16:30:41.159 T:1421     info <general>: special://home/ is mapped to: /storage/.kodi
2026-07-06 16:30:41.159 T:1421     info <general>: special://temp/ is mapped to: /storage/.kodi/temp
2026-07-06 16:30:41.159 T:1421     info <general>: special://logpath/ is mapped to: /storage/.kodi/temp
2026-07-06 16:30:41.159 T:1421     info <general>: Webserver extra whitelist paths: 
2026-07-06 16:30:41.159 T:1421     info <general>: The executable running is: /usr/lib/kodi/kodi.bin
2026-07-06 16:30:41.159 T:1421     info <general>: Local hostname: CoreELEC
2026-07-06 16:30:41.159 T:1421     info <general>: Log File is located: /storage/.kodi/temp/kodi.log
2026-07-06 16:30:41.159 T:1421     info <general>: -----------------------------------------------------------------------
2026-07-06 16:30:41.169 T:1421     info <general>: loading settings
2026-07-06 16:30:41.170 T:1421     info <general>: special://profile/ is mapped to: special://masterprofile/
2026-07-06 16:30:41.196 T:1421     info <general>: Loaded settings file from special://xbmc/system/advancedsettings.xml
2026-07-06 16:30:41.199 T:1421     info <general>: Contents of special://xbmc/system/advancedsettings.xml are...

Portisch · 6 July 2026 15:17

Not much we can do about it. Try again with every new nightly, maybe some latest commit will fix this item.

Ejz · 6 July 2026 15:23

Ok, should I post it in a different thread? maybe in Ugoos AM9 Pro - SoC S6 S905X5-J?

vpeter · 6 July 2026 15:25

Posting in different thread will not solve the issue

Ejz · 6 July 2026 15:28

Well ok, u didn’t say why you can’t do much about it. Who was posting the updated dovi.ko files (and where)? The one actually making them might be able to help?

Portisch · 6 July 2026 16:52

No, this PR does not fix the item of audio delay after played a FEL/TrueHD sample.
But this is maybe TV issue.

Bad live PVR PT with AC3 is broken with LAV enabled.

signde · 6 July 2026 17:09

It’s not limited to unofficial forks, it’s not tied to Dolby Vision, and it’s not even CoreELEC specific. It stems from seamless branching titles ripped from disc with MakeMKV. If your argument of “illegal” shared content is about ripped discs in general, than what are we all even doing here? I thought it was generally understood most of us are using these players for local content you paid for and have ripped from disc.

Team Kodi has made efforts around this before in Omega:

https://forum.kodi.tv/showthread.php?tid=377117

They were trying to solve the literal same problem and those changes shipped with v21.0. The problem with the approach that was merged is it treats the SB points as a seek which has varying impacts depending on your downstream audio chain and why some get dropouts. The proposed fix corrects the PTS timing rather than doing simulated seeks so it avoid the dropouts.

Given that MKV is ubiquitous, I find earlier suggestions that nothing should be done in Kodi about it because it works with BDMV to be rubbish. Good, bad, or indifferent, MKV is the hand we have been dealt. There are reasons many of us want to use that rather than BDMV.

Portisch · 6 July 2026 17:38

The feature doesn’t matter anyway as live PVR get complete broken, stutter and sound stop/break/starts if working at all.

So nothing need to be discussed anymore about it as it’s breaking change. End of this topic until PR is fixed.

Crunt · 6 July 2026 19:15

damn this is unfortunate to hear

neqwdtkukwjaanti · 6 July 2026 19:52

glad to hear it, you’re not the first to have an issue with the internal nfs

the files are broken, period
if you want better handling of broken mkv files then go way upstream and complain to ffmpeg
ffmpeg trips over an error and it ripples all the way down

SamuriHL · 7 July 2026 00:10

The setting is default-off and opt-in, so it’s not a breaking change — with it off, behaviour is identical to stock, PVR included.

That said, your live-PVR point is fair: the sync model targets file/disc passthrough, not realtime streams. I’ve pushed a change that excludes realtime/live streams from the LAV path entirely, so it’s a no-op for live PVR even when the setting is enabled. Thanks for flagging it.

CityCobra · 7 July 2026 15:28

Ok, stop and restart works, too.
Nevertheless, I would expect that after skipping back or pausing/playing, I should be able to continue watching in sync.

It’s not a Dolby Vision issue, as it occurs with other films as well.