[popcornmix]

So what are the options for people that want or need "Sync Playback to Display" for proper 24p and want their AVR to handle the audio (except for running dev builds)?

You don't need "sync playback to display" for proper 24p on Pi. Pi handles 24Hz and 23.976Hz correctly with separate HDMI modes.
You may want "sync playback to display" for, say, playing 24p content on a 50Hz display (with 4% speedup through resampling).

OMX seems to still allow for PLL adjustment, will it stay that way?

omxplayer has always used pll adjustment as part of its A/V sync scheme. That won't change.

[meccs]

So what are the options for people that want or need "Sync Playback to Display" for proper 24p and want their AVR to handle the audio (except for running dev builds)?

You don't need "sync playback to display" for proper 24p on Pi. Pi handles 24Hz and 23.976Hz correctly with separate HDMI modes.

But the RPi2 just switches the TV to 24Hz and throws the 23.976 at it which can't work without the 41 second stutter. That's what "Sync Playback to Display" was used for as far as I understand it.

Edit: I've found this topic here were it was already discussed and you replied there too. Very interesting stuff. I just post it here because it was a bit harder to find since there are a lot of topics about the 24p "issues" some people have: http://forum.kodi.tv/showthread.php?tid=252252
FernetMenta's reply with "you can always use something different than Kodi" says it all though.

[popcornmix]

But the RPi2 just switches the TV to 24Hz and throws the 23.976 at it which can't work without the 41 second stutter. That's what "Sync Playback to Display" was used for as far as I understand it.

No it doesn't. Play a 23.976Hz video and run

Code:

vcgencmd measure_clock pixel

(that is the actually pixel clock output through the HDMI cable)
Then play a 24Hz video and run the same command. You'll find the clock is slightly (1001/1000) higher in the 24Hz case.

Most TV's will just display 24Hz in both cases in their status (some will distinguish them) but they are different modes with different clocks.

A number of other Kodi playforms only support 24Hz, and they will have a drop every 41 seconds without sync playback to display, but that doesn't apply to Pi.

[meccs]

That the "Sync Setting" doesn't do anything for 23.976 @ 24Hz was news to me. Every other discussion said you need to enable it if your TV only supports 24Hz.

24 returned: frequency(29)=74250000
23.976 returned: frequency(29)=74176000

Curious question though: if I don't need "sync playback" on a RPi why does it still adjust the PLL (according to CodecInfo) if I enable it? What is it correcting if there is nothing to correct?
Does it change the HDMI clock to the 24Hz equivalent if I enable "sync playback" and adjusts the PLL to correct it (acts basically if the RPi does only support 24Hz)? I have to test this, anything else wouldn't make sense.

Edit: Clock is the same with and without "Sync Playback". So the question is still: why does it still adjust the PLL if the HDMI clock is correct? (23.976 played at TV with 24Hz)

[popcornmix]

"sync playback to display" enables resampling to keep audio/video in sync.
When display and video exactly match this doesn't do much, although there is a little adjustment done at start of playback to get audio/video offsets down to zero and presentation times at mid-point of vsyncs (may be heard as an audio warble).

This assumes a perfect file. Some files that have been through a few conversion steps or have had adverts cut out may have glitches in the timestamps which the resampling can correct for.

It also can handle the 24fps video on 50Hz display (by speeding audio up by 4%), and other minor speed adjustments to get video and display synced.

If "adjust display refresh rate" is enabled, then the correct 23.976Hz or 24Hz will be chosen regardless of other settings. It makes no sense to use 24Hz when the video is known to be 23.976Hz.

[meccs]

Whatever I do, I can not get 100% smooth playback. It is driving me nuts. My old Samsung TV with integrated media player can play everything smooth (If it's not a file problem) yet I can't not achieve the same thing on my RPi2. My SO doesn't notice the small hitches, but I do. It seems to be random and appears to be a double frame or a slowdown for a fraction of a second. No dropped frames or anything in CodecInfo.
Tried all settings, tried playback from NAS and USB.

No sure if I should open a new topic but here is a log file: http://pastebin.com/v1TV9MqU

RPi2, Philips TV (supports 24p), latest LibreELEC Alpha

Edit: Is there something that lets me check a file if the "time stamps" are correct. In other words, if the file is at fault. Even though it plays good on other devices. (Kodi seems very sensitive when it comes to this stuff imho)

[Mikubo]

Kodi now defaults to MMAL on the RPi but I cannot get smooth playback with that setting. I'd almost abandoned using the RPi for any serious video viewing due to the stuttering thinking it was a hardware limitation. Then I switched to using OMXPLAYER and no stuttering anymore. Yes I tried "Sync playback to display" with Adjust PLL and Resample using MMAL but I shouldn't have to use that and I still experienced stuttering. Using OMXPLAYER and switching off "Sync playback to display" the playback is perfect, i.e. no dropped frames in the stats and visually.

I'm experiencing the same issue on a Panasonic projector and an LG TV using NFS, both mounted and Kodi NFS. I know the Panasonic has perfect 23.976 playback as I've used dedicated Intel & AMD PC HTPCs with it, so no need for "Sync playback to display".

The problem shows itself with 23.976, 1080i50 and most other video material. This is on both an RPi2 and RPi3 running Openelec 6 and OSMC with Kodi 16 - exactly the same issue on both versions and devices.

I'm confused why no one else is reporting this issue, I'm very sensitive to skipped frames but it's pretty obvious when you see it.

Same here using a RPI2 with an Grundig TV and LibreElec 8.0.1. Switching to OMXPLAYER and disabling "Sync playback to Display" works perfectly. No micro stuttering anymore. Thanks!!!

[Arkanon]

I've just come across this problem with an old pi 2 I've set up as a media center with a 5.1 HT system. To get dolby 5.1 I need to enable transcoding, which can only be done using MMAL/Videoplayer and not OMXplayer. On the latest Libreelec MMAL still exhibits this frame skipping everyone's described. no longer an issue.