Blackmagic Forum

Just run into a problem, rendering out a feature film.
Though on the timeline everything is perfectly in sync (one pre mixed stereo track), the moment I render it out I got a 2-3 sec. offset (tried uncompressed AVI and Cineform). After I restart Resolve, it usually works.

PC/Win10/Resolve 17/mostly BRAW

Hi Frank

Can you post a screenshot of your render settings?

A simple DRA with a before-after (e.g source clip and rendered clip) would also help us take a look.

Thanks
Shrinivas

Hi Shrinivas,

here is the link for the screenshots and a log file.

https://fromsmash.com/Screenshots-and-Log

Since the source clip doesn't have audio (we recorded externally, and I got a complete mixed down file from my audio guy, with atmo, dialog and all) - uploading the source file wouldn't make much sense.
The audio offset I get is about 1.5 seconds - but only in the exported file, in the timeline it's perfect.
After I restart Resolve and export again, it's usually fine.
It's hard to nail down, but I'm almost sure, that this only happens only after I swap the audio track for an updated version.

Frank Glencairn wrote:this only happens only after I swap the audio track for an updated version.

How exactly are you doing that?

I get a new audio file from my sound guy, import it in the media pool, delete the old track in the timeline and drop the new one in - nothing fancy. Also the new audio file always has a different name.

I am also getting this issue too, happens to about 1 in 10 exports that I am doing.
I can re-render the exact same job in the render queue and it fixes it, but its seemingly a random occurance?

This is on Mac rendering prores QuickTime, Linear PCM, 480000Khz, 16bit audio using the Main 1(Stereo) Output track

We've had this issue too. Its random. Rendering out to anything but quicktime does seem to work.
I think QT crashes or something. A reboot of the machine also fixes it for us.

For longer outputs we reboot before rendering when we can.

I also encountered this seemingly random out-of-sync issue on a recent project: audio/video sync on timeline was perfect, but the rendered video to MP4 (H265) showed several frames out of sync. I quit and restarted Resolve, verified timeline sync, and rendered again (same settings): the rendered file this time was in sync.

Any news on that Shrinivas?

Hi all,

Just wanted to add we have this issue at our facility too, every now and then a render will be out of sync with audio. This is with both ProRes renders AND IMF's that we are delivering. Very little pattern or reason for it but a restart or even just hitting render again tends to solve the problem.

Can someone from Blackmagic at least acknowledge it as a bug?

Thanks

James

We have repo'ed a number of issues so i expect the new update will have quite a few fixes.

Peter Chamberlain wrote:We have repo'ed a number of issues so i expect the new update will have quite a few fixes.

I just wanted to say thank you Peter for posting this. I wish Blackmagic had the ability / inclination to update more issues with just a simple acknowledgement that the issue was known. Too many threads just languish on the boards with a circular rotation of the comments and no idea if anyone at Blackmagic even reads it....or is working on it.

Again, thanks.

jallen0 wrote:

Peter Chamberlain wrote:We have repo'ed a number of issues so i expect the new update will have quite a few fixes.

I just wanted to say thank you Peter for posting this. I wish Blackmagic had the ability / inclination to update more issues with just a simple acknowledgement that the issue was known. Too many threads just languish on the boards with a circular rotation of the comments and no idea if anyone at Blackmagic even reads it....or is working on it.

Again, thanks.

exactly. BMD need a Bug Report and Feature Request system for users. Lots of wasted time on both sides.


I'm having this issue too. Audio rendered out of sync. Simple re-render didn't.

Peter Chamberlain wrote:We have repo'ed a number of issues so i expect the new update will have quite a few fixes.

Thanks for looking into it Peter.