Canon 7d Audio sync with zoom H4 over long video clips

[artpimpjulz]

 I use the Q3hd to shoot live band vids - My only solution is to use Final Cut to slow the footage to 99.9042% - and even then it is still a frame or 2 out after 10 mins - making audio mixing impossible.

the other cameras i use are fine, from a £100 canon ixus to a £3k Sony V1 - all stay in perfect sync

[franciscanfriars]

Set H4 to wav44.1khz/16bit and rec. at 24fps on 7D and it'll always be in sync.

God Bless.

[kirikset]

It is not a problem at all) I just use a standalone dualeyes sound sync program and all you have to do is select "correct for drift" and it automatically corrects audio drift. DualEyes also syncs audio with audio sample accuracy and not just with video frame accuracy. Also you dont need a slate any more)

[skonatrix]

its out of sync because ur sample rate was diff on the ZOOM than on ur camera.

[SquickyPantsy]

is there any connection with the frame rate?

[onelonedork]

@SquickyPantsy No it appears the the older Zoom h4 doesn't have a very good internal clock. Audio can drift as much as 20 frames over the course of a long clip. If it were a frame rate issue you loose about 6 frames per second. The drift would be much more dramatic.

[galtyyy]

@onelonedork

Do you know how long ago the improved internal clocks started coming out with the zoom H4s? 

[jallsbrook100]

How did you connect the zoom to the camera?

[onelonedork]

@jallsbrook100 In this video the zoom is recording audio and the camera is using its on board mic, there is no connection between the camera and the zoom h4.

[JWD96]

where can I find this mount you used to put the H4 on to the 7D?

[onelonedork]

@JWD96 Its a flash bracket i bought used on ebay.

[papikache]

Onelonedork could it be that you did not sit them right in the timeline? I see that during your clip at 1:18m you had them almost lined up but not entirely. did you try putting the marker(red line) as the canons audio started instead of putting it in the middle of the H4n's audio? try to do that and see if it fixes the frame drops.

[onelonedork]

@papikache Its actually not an H4n its the older H4, and there is a known problem with the h4 holding sync. The audio is sync'd at the beginning and slowly drifts out of sync as the clip goes on.

[sherwood1138]

Was that shot with 44.1 as opposed to 48K? What frame rate was the camera going?

[onelonedork]

@sherwood1138 48k 16bit was what the zoom h4 was set at. The 7d was running at 1080p. I've actually had the chance to test more then one z00m h4 and it turns out that the the original zoom h4's timing can very from unit to unit, Mine happened to be off by 100.047% however another was at 99.085%. The zoom h4n has a little better quality control every one i've tested has been dead on with the canon 7d.

[revup67]

@onelonedork - wow this is great news as I have both and with latest firmware updates on both as well. Were both at 29.97 FPS ? Too bad you cannot do a line out form the H4N directly into the Stereo mic input on the 7D. So another words the two built in H4N mikes would override the mono mic on the 7D via the stereo line input so no syncing would be necessary - many thanks!

[starfedrogue]

Thanks, very useful. I'm thinking of picking up a 7D with out board recording solution later this year.

[onelonedork]

@starfedrogue there are rumors that canon will release a new firmware update for the 7d that will disable the AGC and allow you to set your own audio levels, but i'll believe it when i see it.

[revup67]

@onelonedork - if you want a firmware update passed through quicker call their tech support line and make that request @ 866.261.9362 - they've sent two of my requests already to HQ

[onelonedork]

@revup67 I've been spamming them with requests for this update as have many others i know. Canon often movies very slow in that regard. I'll start calling there support line, thats a good idea.

[editorfree]

what frame rate were you shooting at for this test?

[wildaboutimages]

Thanks!

[DooWatchaLike]

I did the same test with the Canon EOS 7D shooting with 25 fps and the Zoom H4N recording with 48 kHz 24 Bit. Over a 11 minute duration it was in perfect sync, not 1 frame was shifting! Lucky me! :o)

[onelonedork]

I think it might be poor quality control in H4 series. I tested out a friends H4 and the timing over 10 min was 100.02 off. I have an H4N on order. I'll post a video when ever it shows up.

[4thwalltvandfilm]

Will the h4 do 48 kHz recording?

[onelonedork]

Yes it'll do 44.1 48k and 96k

[4thwalltvandfilm]

Great to hear. Thanks very much! I am looking at getting the R16 for 8 tracks of live recording in the field so, hope it is the same as the h4 in that case.

[4thwalltvandfilm]

audio sync issue may be from the 44.1 khz sample rate vs 48 khz that most video uses to sync to 23.976 & 29.97 fps.

[onelonedork]

Could be i'll have to try it with a 48k sampling rate.

[BrandedChannels]

I just read about PluralEyes software that makes audio sync a breeze - if you're on mac and Final Cut Pro. Unfortunately I'm on PC and Premiere Pro (think you are too?), so I'll have to wait until they will start to support that...

[onelonedork]

I do use premiere, and its actually not to bad, The files are time and date stamped So a loud noise is really all you need to sync them up.

[onjoFilms]

It's interesting. I'm thinking of getting the 7D just because it records 29.97 and not 30fps like the 5D. But it appears there is still some synch issue darn it. Maybe the Zoom is recording at 30fps lol.

[onelonedork]

It probably is the zoom, i don't think it has any kind of stranded sync in it. But on a bright note, mine is always exactly 7 frames off at the 10 min mark. So it looses less then a frame a min which is better then 5d, and doesn't make much difference on pitch.

[onelonedork]

I tried both 60p and 29.97p both had the same result. I didn't try 24p or 25p. I also have yet to try my fostex out with it.

[b4uaskimagod]

What frame rate did you shoot? 25fps or 29frs? or even 24fps.

Have you tried a different frame rate on the camera?