Keynote intermittently fails to play media files on some HDMI connections

And I join you again, dear reader, after having entirely reinstalled OSX on my MacBook Pro, assuming that it would fix the issue. It took about four hours.

It doesn't fix the issue.

So, here's where we are:

• HDMI with sound fed through HDMI: video/audio occasionally fails to fire
• HDMI without sound (ie sound fed through internal speakers): all works well
• VGA: all works well

I have also bought a $15 VGA-to-HDMI adaptor. It's plastic, it's rubbish, it makes the picture look a bit gray, but it stops the issues.

So, here's the plan. After this exhaustive testing, I now intend to make a new thread with a bit more of a focused report.

...later...

Under "System Preferences > Energy Saver > Power Adapter", I've unselected "enable power nap", and shoved it up from 5 minutes to 1 hour. I've also removed the screen saver ("System Preferences > Desktop and screensaver > Screen Saver") which was set to go off after five or ten minutes. The screen wasn't going off, but it *could* have been the case that some energy saving was occurring.

In Keynote>Preferences, I've turned off TouchID; and disabled remotes.

I've attempted to recreate the error on my HDMI monitor, without success. This is either good news or bad; good news that I've fixed the error, or bad news that I've just failed to recreate the issue.

...later...

I was able to visit a venue where it hasn't worked before, and attempted, with the same slide deck, to reproduce the issue. One of the university's techs was also present.

I couldn't reproduce the issue.

The only difference, as far as I could work out afterwards, was that the AUDIO was not routed through the HDMI connection, and instead was playing from my machine's speakers. And perhaps this is something to do with the issue - the Mac's audio times out after a while after there's no audio (you can hear a very soft click if you listen to the output of the headphone socket); and perhaps Keynote is spotting that there's no longer any valid audio connection and hanging when it sees the audio. Hitting 'escape', to come out of a presentation, does I think make a 'doink' noise, and that might assist the audio circuitry to wake up again.

This might also explain why my HDMI monitor doesn't exhibit this issue (it doesn't have any audio); and why it seems to not always be an issue with some systems - perhaps those are the ones I'm not feeding audio via the HDMI cable.

I intend to carry on testing this - but the audio output might be part of the issue here.

As an addendum to the above: the above tests appear to point to an issue with the audio. If you don't feed audio through HDMI, things appear to work just fine.

Since I installed Soundflower a while ago, and someone else who's commented here has also installed Soundflower, I'm wishing to test whether Soundflower has any issues. While I uninstalled it a long while ago, it's still appearing in my sound preferences as a valid input/output. I also have Audio Hijack installed by Rogue Amoeba, and it strikes me that this is also something to do with the sound output, and thus I am quite keen to remove this from the audio chain as well.

Accordingly, I'm currently rebuilding the computer entirely from scratch, reinstalling OSX and the few actual programs I use. This should enable me to see if there's an incompatibility.

The good news: I've managed to replicate the issue on my own television, so I think I may be able to know categorically whether it's an issue with these pieces of software. This might also explain why this bug is seemingly quite rarely reported on the internet, since I can't imagine Soundflower, or AudioHijack, being used by many OSX users.

Thank you, Nicholas, for at least making me feel I'm not talking to myself! 🙂

Today, I removed any vestiges of Soundflower from my system (I'd uninstalled it a long time ago, but it still appeared as a valid audio output for some reason). I was considering a complete reinstall of the system, too.

Might I ask you what type of Mac you have? (Touchbar?)

Hi, Nicholas,

I use a Macbook Pro with USB-C connections. I've used the official Apple HDMI connector and an Anker one. Both exhibit the same issue.

The audio I play is not protected by any form of DRM, and I have ruled out copy protection as an issue; it is DEFINITELY an issue with HDMI connections, as you have highlighted.

I do not have this issue with VGA; perhaps the right thing for me to do is to source a VGA -> HDMI adaptor, slightly unintuitively.

Thanks for the response. I think I've now had this issue with enough wildly different connections and dongles that I believe it is a software issue, and not a hardware one.

I'm wondering if it's something to do with the TouchBar component, and that device's generation of thumbnails somehow.

Hi, Nicholas, and thanks for your suggestion.

Permissions aren't required to play - for example - WAV audio files; and they intermittently don't play either. Even videos that don't play WILL play quite happily if you hit 'escape' then 'play' again. I can fairly conclusively state therefore it isn't an issue with the HDMI cable.

I'd love to suggest to venues that they only use VGA and separate audio. Perhaps it's as simple as not bringing an HDMI cable! Sadly, that's not always an option available to me.

I notice that Keynote has had another update; so we'll see if that might have fixed the issue. I doubt it, though.

This has left me with a very sour taste in my mouth about investing a fair amount in a top-of-the-range model. It is simply useless for the one requirement that I have of it. If I understood what the issue was, I'd be happier.

Good news - of sorts. I managed to reproduce the issue - once - on my television when feeding it with audio.

Bad news: I've no idea what made it stop. But at least we know that audio is, in some way, involved. This is progress! And even if I am just talking to myself here, at least this is helping me.

Additionally...

When testing it on my HDMI television, it appears to work fine. But one theory I now have is that the video only doesn't work if you leave the presentation alone - there seems to be a timeout after which media files fail to play (unless you exit out of presentation mode and go back in). (It also works just fine on my HDMI monitor - but, again, it might be a timeout, since when I test it I'm running through the slides one after another).