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Intel VAAPI howto with Leia v18 nightly based on Ubuntu 18.04 server
pretty simple:
passthrough audio ON: sync playback to display: OFF
passthrough audio OFF: sync playback to display: ON
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(2015-09-16, 17:38)wsnipex Wrote: pretty simple:
passthrough audio ON: sync playback to display: OFF
passthrough audio OFF: sync playback to display: ON

I think what is confusing to most people is that with both settings:
"adjust refresh rate to match video" & "sync playback to display" enabled it would appear that they would work against each other.
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(2015-09-16, 17:28)ggp759 Wrote:
(2015-09-16, 15:16)FernetMenta Wrote: the point is that you can't adjust refresh rate to match video to a 100% match.

Ok. Saw you are saying that i should have both options enabled?

No. Sync Playback syncs perfectly the fps to the videoclock. Simplified, whenever we change the front with the backbuffer one fps is displayed. This happens fps count a second. Fully in vsync -> perfect video. Problem here is: If video and audio don't match exactly.

Use case a) The VSync Clock runs at 23.99 fps and not at 23.976 fps -> no problem for video as it is just displayed "a bit" faster -> you won't notice. Cause in perfect vsync 23.99 fps are displayed per second - perfectly matching your screen, just like a clock - always doing: tick, tick, tick e.g. frame, frame, frame - the clock just runs faster as a 23.976 clock would run - no one cares. Problem comes into play, when you have audio. Cause audio and video would go ahead of each other. Therefore one needs to do something when this is happening.

With passthrough audio: we only have two choices drop or dupe and that you can hear very loud if you have bad luck, it makes a famous psssst noise to correct this offset.
Without passthrough audio: We resample a bit and video stays perfectly in sync and you won't even notice anything

=> Reason why you should disable it when you passthrough.

In a perfect world where videos are really exactly 23.976 fps and your refreshrate is really 23.976 hz -> Sync Playback does not harm (even if you passthrough), but it won't be able to help you - as everything is perfect already. And: world is not perfect.

Use case b) You play 59.94 fps content at 60 hz -> vclock "speeds it up" automatically, cause swapBuffers every 1000 / 60.0 ms vs. 1000 / 59.94 ms -> audio needs to be speed up too.
With passthrough: drop samples (ugly, bad experience)
Without passthrough: resample with a factor > 1 - audio will get a little bit higher in tone -> but you won't realize.

Adjust Refreshrate to match video is something else - it tries to find a refreshrate, so that Refreshrate % (modulo) fps == some even non fractional value. 25 fps at 50 hz is fine, 23.976 fps at 23.976 hz is fine. 23.976 at 24.0 hz -> not fine. But with RefClock -> no issue video wise.

So to summarize:
- Use Adjust Refreshrate to match video: good precondition to have the Sync Playback do a nice job afterwards
- Use Adjust Refreshrate to match video: also if you are a passthrough audio user - cause 23.976 fps content + passthrough audio played at 60 hz - won't work without either visual stutter or audio drops.
- Passthrough audio sucks for "perfect playback" as video clock might not match fps exactly, we need to drop / dupe or resync after 200 ms off
- Enable Sync Playback to Display _if_ you don't use passthrough audio as it cares for perfect video while maintaining your audio in sync without you noticing.

Edit: Not covered in here: What happens if you play 24.0 fps content at 60 hz? How would you play 23.976 fps at 60 hz? -> Some wikipedia for the dear user able to read: https://en.wikipedia.org/wiki/Three-two_pull_down

Personally: I don't use passthrough audio at all - I have a 5.1 capable LPCM receiver which I feed directly. Since we have dcadec support - I even can decode DTS-HDMA and have perfect audio also in combination with perfect video.
First decide what functions / features you expect from a system. Then decide for the hardware. Don't waste your money on crap.
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(2015-09-16, 17:38)wsnipex Wrote: pretty simple:
passthrough audio ON: sync playback to display: OFF
passthrough audio OFF: sync playback to display: ON

So in my case that the setup is:

Mediaplayer>AVR>TV

I use Audio Profiles switch http://forum.kodi.tv/showthread.php?tid=200081 to swich between AVR Profile and TV

So is better if i use TV from Audio also to have sync playback to display or my avr (as referred pages ago) auto sync ?

Thank You
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Just disable passthrough and enable Sync Playback to Display always.
First decide what functions / features you expect from a system. Then decide for the hardware. Don't waste your money on crap.
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My 3 cents to "Sync Playback to Display" - I've noticed that with this option enabled my audio floats in really bad way - it speeds up and slows down making sound really bad (worst moments are with soundtrack playng in the background - on music you can hear very well this effect). With "Sync Playback to Display" disabled everything seems to be ok.

My audio setup: Beebox-->USB DAC-->Amplifier.
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No Debug Log - no problem.
First decide what functions / features you expect from a system. Then decide for the hardware. Don't waste your money on crap.
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So essentially with passthrough disabled LPCM will be sent with all 5.1 channels just won't see the useless lights on receiver "DTS, DTS-HDMA, etc."
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(2015-09-16, 18:55)oshan Wrote: So essentially with passthrough disabled LPCM will be sent with all 5.1 channels just won't see the useless lights on receiver "DTS, DTS-HDMA, etc."

Hehe - exactly :-). Also note: Some AVRs do special things when they receive DTS / DTS-HD - e.g. boosting something, a sound some people like. But it's most likely the light that people love.

It's the same insane thing like buying a DAC - that only does 16 bit and max 48 khz - as I needed to teach someone that had a 3000 dollar DAC running on android and everything was downsampled to audiotrack's system samplerate.
First decide what functions / features you expect from a system. Then decide for the hardware. Don't waste your money on crap.
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(2015-09-16, 18:52)fritsch Wrote: No Debug Log - no problem.

What else do you need fritsch? There is no special message in any logs, I just hear it. Should I enable additional logging on Kodi?

BTW I've also small issue with next option - "pause playback during refresh rate change" (or similar - I try to translate into english). when I start playback there is no video signal but audio starts for about 0.5 sec and then resumes after refresh rate change. So it seems to be little bit unusual.
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No - Debug Log is sufficient. You are aware that you run an alpha build with rough edges, right?
First decide what functions / features you expect from a system. Then decide for the hardware. Don't waste your money on crap.
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(2015-09-16, 18:59)fritsch Wrote:
(2015-09-16, 18:55)oshan Wrote: So essentially with passthrough disabled LPCM will be sent with all 5.1 channels just won't see the useless lights on receiver "DTS, DTS-HDMA, etc."

Hehe - exactly :-). Also note: Some AVRs do special things when they receive DTS / DTS-HD - e.g. boosting something, a sound some people like. But it's most likely the light that people love.

It's the same insane thing like buying a DAC - that only does 16 bit and max 48 khz - as I needed to teach someone that had a 3000 dollar DAC running on android and everything was downsampled to audiotrack's system samplerate.

With recorded PVR stuff, I get audio skips, which are worst with sync on and passthrough off, and best with sync off and passthrough on Rolleyes

also, as long as those DACS are branded as NOS or "analog in sound" and is expensive enough, people will be idiots and buy them.

Love my 32bit 384kHz DACLove
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@Ney: Afaik you run the non supported OE build ... which has a complete different mechanism to sync. - might be possible. But as said before: no Debug Log no issue. If you run the ppa - post it here - if not - send me an email.
First decide what functions / features you expect from a system. Then decide for the hardware. Don't waste your money on crap.
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Yeah fritch, i know no issue. Just wondered out loud, I will try Jarvis when I get time and/or get you logs Smile
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@Ney: makes me wonder anyways. As this runs in my living room - cannot afford that some of the addons, the wife is using, won't work anymore :-) without any issues.
First decide what functions / features you expect from a system. Then decide for the hardware. Don't waste your money on crap.
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