Catchin’ Sync

Catchin’ Sync is an invaluable tool for anyone in the film industry. It’s a genius iPhone APP that is, in my opinion, imperative for any editor to have to properly correct an audio visual delay.

Harrison Meyle, Dialogue Supervisor | Emmy Recipient
Warner Bros

One and only Sync Checking app.

Catchin' SYNC allows you to capture and manually determine audio SYNC issues of your video playback device. In almost all cases, where audio and video playback passes through separate devices (i.e Audio through receiver, video through LCD TV or Projector etc.) there will be advancement or delay on the audio signal, making the viewing experience unpleasant. Catchin' SYNC will help you determine if your system is in SYNC or has a lag and by how much in milliseconds or frames. With that information you can add appropriate amounts of delay to your signal, and get everything play along properly in SYNC. You can use the offset information in your editing software (AVID Media Composer, Adobe Premiere, Pro Tools, Nuendo, Final Cut X etc.) and compensate. Most video hardware interfaces like Blackmagic and AJA will also have settings to do this. For home users, most Receivers and TVs, Apple TV and even VLC will let you enter this information. So, if your audio and video are out of sync, Catchin' Sync will help you synchronize them!

Catchin' SYNC let's you visually observe the sync points of the video and audio, and let's you move the audio back in sync by touching the screen to get a reading. With up to 240fps recording capability, its accuracy is unquestionable. No need to spend wads of cash on hardware devices!

Show and tell video from Mike from Pro Tools Expert:


***Please note, -when prompted- you need to “allow location services” for Catchin SYNC to be able take videos or use videos from your library (after in app purchase)******If you have said no initially and can’t get the app working, you need to go to your device’s Settings. Under General, Reset, please “reset location services and privacy” and relaunch the app.***
Catchin’ SYNC operation notes

Catchin’ Sync is a utility that helps you determine the amount of synchronization error between video and audio signals in your playback system. A sample video is included with this app for you to see how the technique works. Purchasing the full access allows you to record or use your own videos.

About the “Measurement Frame Rate” parameter: This setting has no effect on the frame rate of the test recording. Catchin’ Sync will always record at the highest frame rate available (240fps on iphone 6, 6s, 7)

“Measurement Frame Rate” refers to the frame rate of the material you are testing. To enable this option, change “Offset measurement unit” from the default “milliseconds” to “frames per second”.

How to use:
    1- Select a video file to play on your system that has clear sync points. Best examples would be frame-long countdowns, or pips (pops). Anything with a clear visual reference and a sharp sound should work fine. Make sure that the visual reference exists somewhere in the middle of the screen. (visit our Downloads page for videos you can use)
    2- Play this portion of the video on your screen for about 5-10 seconds and record it with Catchin’ Sync (only if you have purchased full access). Do this with the sound turned up higher than usual and no other noise interference.
    3- Find an appropriate visual sync moment on the recorded video by using the thumbnail strip above the video, and then frame by frame by swiping the main video window gently. You can do frame by frame adjustments with on screen buttons as well.
    4-While the video is parked at the desired frame, touch the lock button to unlock the audio layer so you can move the waveform back and forth independently of the visuals. Slide the waveform with your fingertip to line up the audio event with the red line.

At this point, the offset amount will be displayed in milliseconds by default. Make sure to compensate for your device’s offset amount as well as other settings in the settings tab. Find listed device offsets in Device Info section on the right.

    ♦ Sample recording that is supplied with the demo is of a 25fps video playback off a TV screen.
    ♦ If possible, perform the above steps on multiple points on the video to achieve better accuracy.
    ♦ Positive offset value means audio is advancing the video on your system.
    ♦ Negative offset value means audio is delayed.
    ♦ Shake your device to reset the calculation.
    ♦ Compensate for distance if you’re far from the sound source.
    ♦ You can also measure approximate distance of distant events like lightning, fireworks, flare gun etc.

Device Info

Here’s a list of known average device offsets. Enter this offset amount in Catchin’ Sync settings to compensate. If your device is not listed here please check back at a later time.

WARNING: When Apple updated IOS to version 9 it presented a bug that affects iPhone 6 and 6+. This bug makes the audio latency go between 30ms and 60ms. The correct offset is 30ms, so do your measurements with that setting. And do 2 or 3 readings, don't use the 30ms higher reading. This bug remains in IOS 10+.

This bug does not affect Iphone 6S and 6S+ devices.

 iPhone X (IOS 11)  +23ms (audio delayed) 240fps
 iPhone 7, 8, 7+, 8+ (IOS 10,11)  +25ms (audio delayed) 240fps
 iPhone 6S (IOS 9,10,11)  +25ms (audio delayed) 240fps
iPhone 6 & 6+ (IOS 9,10,11) +30ms (audio delayed) 240fps See Warning above
iPhone 6 & 6+ (IOS 8) +20ms (audio delayed) 240fps
iPhone 5 & 5s (IOS 6&7): 0 ms 60/120fps
iPhone 5 & 5s (IOS 8&9): +20ms (audio delayed) 60/120fps
iPod Touch 5 (IOS 6&7): 0 ms 60fps
iPod Touch 5 (IOS 8&9): 0 ms 60fps
iPhone 4s: -40ms (audio advanced) -/+ 8 ms
iPhone 4: +53 ms (audio delayed) -/+ 8 ms
iPod Touch 4: +53 ms (audio delayed) -/+ 8 ms
iPad Mini Retina (IOS 8&9): +30 ms (audio delayed) 60fps
iPad 5 (Air): +20 ms (audio delayed) 60fps
iPad 3 (Retina): -29 ms (audio advanced) -/+ 8 ms
iPad 2: -32ms (audio advanced) -/+ 8 ms
Test files

Following are test videos in standard frame rates and popular codecs. Please download and use in your measurements. Right click or control+click to download them to your computer.

23.976 fps
H264 | PhotoJpeg | ProRes | DNxHD |
24 fps
H264 | PhotoJpeg | ProRes | DNxHD |
25 fps
DV PAL | H264 | PhotoJpeg | ProRes | DNxHD |
29.97 fps
DV NTSC | H264 | PhotoJpeg | ProRes | DNxHD |
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