Mac OS X - MP4: Sound stutters and/or is out of sync

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Sirius26 Offline
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Post: #1
Hardware: Mac Mini Server 2010, Core 2 Duo 2,66 GHz, 8 GB RAM, 128 GB SSD + 500 GB HDD, NVIDIA GeForce 320M
OS: Mac OS X Yosemite 10.10.1
Kodi 14 Beta 3

Hi,

I have a problem with MP4 videos. Video is okay but the sound is stuttering and/or out of sync. The video files are on my NAS but the problem persists if I copy them to the local SSD or HDD.

My Mac is connected to an LG TV via HDMI.

Video settings/Playback:

Adjust display refresh rate to match video: on start/stop
Pause during refresh rate change: 5.0 seconds
Sync playback to display
A/V sync method: Video clock (Resample audio)

Video settings/Acceleration:

Render method: Auto detect
Decoding method: Hardware accelerated
Allow hardware acceleration (VDADecoder): enabled

System settings/Audio:

Audio output device: HDMI
Output configuration: Optimized
Resample quality: Medium
Passthrough: disabled

When I play the affected video files with VLC, Quicktime or Movist everything is okay.

How can I solve this sound problem?

Thanks in advance
(This post was last modified: 2014-11-22 14:50 by Sirius26.)
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wrxtasy Offline
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Location: Perth, Oz
Post: #2
Download this OSX program and run the problem video files through it.

http://www.emmgunn.com/mp4tools/mp4toolshome.html

Settings for MP4 tools:

- Both Video and Audio - Passthrough
- Settings - Extract Tracks
- Track Selection - All Tracks
- Device - General
- Media Type - Movie

NOTE: anyone else reading this and having issues with video files is advised to follow the above procedure.

It works for both my Mac and my RPi with problem video files.
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Sirius26 Offline
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Post: #3
Thanks for your answer, wrxtasy. I'l try this out.

But I don't think that the video files are corrupt because every other player doesn't have a problem with them.
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wrxtasy Offline
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Post: #4
You may say that but i have video files that seem to have issues when playing in XBMC exclusively, yet are OK on every video player on my Mac.
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Sirius26 Offline
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Post: #5
I've extracted a few video files with this tool but the audio problems still persists.
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wrxtasy Offline
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Post: #6
Cannot help anymore.

Install a working stable version like Gotham 13.2 on the Mac and not a bleeding edge Kodi Beta3.
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Sirius26 Offline
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Post: #7
I've installed the stable version of XBMC 13 before: same sound problems. So I tried the beta of Kodi 14.
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wrxtasy Offline
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Post: #8
Only other suggestion would be to have the OSX app - Activity Monitor running in the background and see if any process is hogging system resources.
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Sirius26 Offline
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Post: #9
The only process what's taking resources is Kodi Smile

I've deleted Kodi 14 Beta 3 completely and installed Kodi 14 Beta 5. Now it's somewhat better but some videos are still out of sync. No problems with these videos on VLC, Movist or Quicktime.
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wrxtasy Offline
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Post: #10
Just had a detailed read again of your Playback Video Settings.

have you tried turnings this to Off: (Leave everything else the same)

Adjust display refresh rate to match video ?

You can also try:

Settings > System > Audio Output > Keep audio device alive - Always

Failing that:
I don't suppose these problem files have Subtitle tracks ?
If so run them through MP4tools again only this time select:

Track Selection - manual

then only tick the Video and Audio tracks in the main window before hitting Convert.

Another handy OSX app is Mediainfo from here:

http://mediaarea.net/download/binary/med...71_Mac.dmg

This will give you detailed info on containers and streams and more, contained within video files.
(This post was last modified: 2014-11-29 17:40 by wrxtasy.)
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