Newbie here - not a professional by any means, but I know my way around some terminology and settings. I created a 46 minute video shot in 4k 24fps on a Sony a6400 with additional 4k 24fps footage from Sony A7rII. Everything works just fine in the timeline - perfectly synced (and the audo was captured in-camera). Upon export, the audio creeps out of sync. It starts fine, but by the 46 minute mark it is almost 2 seconds out of sync.
I've tried a few different export settings, but it takes about 4 hours to export, so I can't really troubleshoot very efficiently. The footage info is below:
Type: MPEG Movie
File Size: 18.75 GB
Image Size: 3840 x 2160
Frame Rate: 23.976
Source Audio Format: 48000 Hz - 16-bit - Stereo
Project Audio Format: 48000 Hz - 32 bit floating point - Stereo
Total Duration: 00:46:13:12
Pixel Aspect Ratio: 1.0
Video Codec Type: MP4/MOV H.264 4:2:0
My export settings are:
Preset: Youtube 2160 4k (I also tried Match Source - High Bitrate - same result)
Bitrate Setting: I tried both VBR 2 Pass (Target & Maximum 40) and VBR 1 Pass. Have not tried CBR yet.
Audio Codec: AAC
Audio Sample Rate: 48000 Hz
Is the audio still out of sync when importing the export file into Premiere.
Ah ha! I imported the export file back into premiere and it is back in sync when played in the program. Obviously I'm still left with the issue, but you seem to have an idea of what this means.
What are your computer specs? Perhaps it is not robust enough to playback such a long file at its current bitrate. I would make sure the file is on a fast drive. You can also upload the file and check it online, you can test on a faster computer, or create a HD version to rule out any hardware issues.
Thank you! I didn't really expect that my computer would be the issue as it's a 2018 Macbook Pro. However, you were rght! I uploaded it and the audio is perfectly synced up!
I also have one of these computers, bennett. 4K is really a wolf in sheep's clothing. I may have to stick to my new M1 MacBook Pro for 4K playback. Thanks for your feedback! It will surely help others.
I was thinking it would be variable frame rate footage, but it looks like your footage is all from a camera, no phone footage, etc.
Can you export just say the last 5 or 10 minutes and check that, see if it's still out of sync like the full export.