Mini Recorder A/V Sync

Hi,

We have been using the Mini Recorder with Thunderbolt on Mac OSX El Capitan (10.11). We are noticing that when recording in QuickTime Pro or any custom software we creating using AVFoundation, the audio is delayed and out of sync with the video. Audio meters on the computer confirm this even prior to hitting record. Final recording is thus out of sync.

Oddly, this sync issue does not occur in the BlackMagic Media Express software.

Using any other microphone input separate from the BlackMagic mini-recorder does not have an audio delay.

The latest device drivers have been downloaded and are being used. Computer is latest MacBook Pro with top of the line memory / hard drive / etc.

Our current only option is to split the mic source from the video and run it as a separate input on the mac instead of through mini recorder.

How can we solve the audio delay issue?

There are numerous posts about audio delay throughout here but could not find anything recent nor anything related to the mini recorder specifically.

Thanks,
James

Hi,

We have been using the Mini Recorder with Thunderbolt on Mac OSX El Capitan (10.11). We are noticing that when recording in QuickTime Pro or any custom software we creating using AVFoundation, the audio is delayed and out of sync with the video. Audio meters on the computer confirm this even prior to hitting record. Final recording is thus out of sync.

Oddly, this sync issue does not occur in the BlackMagic Media Express software.

Using any other microphone input separate from the BlackMagic mini-recorder does not have an audio delay.

The latest device drivers have been downloaded and are being used. Computer is latest MacBook Pro with top of the line memory / hard drive / etc.

Our current only option is to split the mic source from the video and run it as a separate input on the mac instead of through mini recorder.

How can we solve the audio delay issue?

There are numerous posts about audio delay throughout here but could not find anything recent nor anything related to the mini recorder specifically.

Thanks,
James

I think the easiest thing is to skip AVFoundation and use the Decklink API instead. Then you will also get better control of the capture device and less changes with different versions of Desktop Video . The drawbacks are that you need to write some C++ and perhaps do some more format conversions..


Have you tried different versions of Desktop Video?

Edit: Realised that you might not want to write any code.. have you looked at other apps to record from the device (which implement the Decklink API)?

I have the same issue. FYI. It's mysterious that it works for media express but not anything else. It's obviously not the device....

I have the same issue. FYI. It's mysterious that it works for media express but not anything else. It's obviously not the device....

You could try (just as a test and good information for me..) to record using LiveReplayer. You can only get a mp4 file and a choice of bitrate between 1 and 80Mbps. It's free but you need to create an account to login. See http://livereplayer.com. It's the button in the upper right called "Start recording" which records to a file, recording preferences can be found the the preferences window under the tab "Inputs".

If the audio is in sync, then it should be fine for all apps that don't use AVFoundation for capture.

Are you running any other audio routing programs? I've used a MacBookPro with 10.11 using the MiniRecorder via TB into Wirecast for 3 recordings this week and have not had one issue with AV sync. This is from input via the SDI connection.

Are you 100% positive that the audio that is attached to the video is in sync when it hits the MiniRecorder.

I just tried recording some 1080i50 using Apples sample code for recording, https://developer.apple.com/library/mac ... Intro.html.

The audio and video was synchronized, any other audio software installed?

I was wondering if you found a solution to this issue, Im using MAX/MSP/JITTER and Im experiencing the delay in the SDI audio feed. But the audio is totally in sync using Black Magic Software.