Syncing/Merging A Video File 29.97fps and Two Audio files at 48000hz

Report · Nov 18, 2016

I'm recording for an online video series and am admittedly not very experienced. I have two rodelink wireless microphone kits that I used to record audio that I was hoping to match with a video interview that I conducted using an Ipad to capture the audio.

I did the clap test so that I could align my audio files and then hopefully ditch the audio from the ipad, and just used my high quality mic audio with the video.

As I began to sync/merge(please forgive me, as I don't know the proper terms for each) the files, I noticed that as the video went on, though everything appeared seamless in the beginning, as the video continued to run, the audio an video became out of sync.

I noticed that the video file is 29.97fps(not sure if it is drop frame on non-drop frame) and the audio files are 48000hz. Is there anyway to reconcile this problem using Premiere Pro? Also note, I own and am using a mac, just in case that is important.

I've tried to modify the timecode and have the fps switch to 24fps but it doesn't seem to have worked. I also tried, though it may sound silly to change the audio timecard to 29.97fps...again to no avail.

Thanks in advance for any help and/or advice.

P.S. If it happens that I'll just have to reshoot it all, are there suggestions for hz settings I could just switch my mics to so that I won't have this issue going forward?

Report · Nov 18, 2016

There is a good chance that your ipad recorded the video using variable frame rate, this might be the reason the audio has drifted, Try converting it to constant frame rate with a program like Handbrake.

Report · Nov 19, 2016

Thanks for the suggestion. I downloaded Handbrake and definitely see how it can be tremendously useful.

Unfortunately I've tried a few combinations of changes, all including constant frame rate, and yet still, I'm having problems syncing the separately recorded audio.

What happens is I've had no issues combining my two separately recorded microphone audio files using Rode Rec, in conjunction with my Rodelink wireless microphones. So the audio is set, but then when I align the audio with the video shot with my ipad, even after switched to constant frame rate...at first, they line up fine, but as the video continues to play the slowly begin to unsync, and by the end of the interview there is a very noticeable delay. I use the original audio on the ipad video, and then mute or remove it once I've aligned the higher quality audio files.

I don't have a lot of money, so I invested in the audio recording equipment first and figured I could just easily aline it with what I feel is usually good enough video from my iphone or ipad, all shot seperately.

Do you have any suggestions on what I might be able to do? Even if not to fix this particular interview video, should I maybe record at a different Hz? Or is there something else I'm missing here? Perhaps my problem is something else entirely.

Anyways, any help is appreciated, and thanks again for your thoughts already.

Report · Nov 18, 2016

Ipad record Variable frame rate

Convert it to constant frame rate using Handbrake from here

https://handbrake.fr/

then do the lip-sync

Muhannad,

Report · Nov 19, 2016

Thanks for the suggestion. I downloaded Handbrake and definitely see how it can be tremendously useful.

Unfortunately I've tried a few combinations of changes, all including constant frame rate, and yet still, I'm having problems syncing the separately recorded audio.

What happens is I've had no issues combining my two separately recorded microphone audio files using Rode Rec, in conjunction with my Rodelink wireless microphones. So the audio is set, but then when I align the audio with the video shot with my ipad, even after switched to constant frame rate...at first, they line up fine, but as the video continues to play the slowly begin to unsync, and by the end of the interview there is a very noticeable delay. I use the original audio on the ipad video, and then mute or remove it once I've aligned the higher quality audio files.

I don't have a lot of money, so I invested in the audio recording equipment first and figured I could just easily aline it with what I feel is usually good enough video from my iphone or ipad, all shot seperately.

Do you have any suggestions on what I might be able to do? Even if not to fix this particular interview video, should I maybe record at a different Hz? Or is there something else I'm missing here? Perhaps my problem is something else entirely.

Anyways, any help is appreciated, and thanks again for your thoughts already.

Report · Nov 19, 2016

Unless the recording devices are locked together they will always drift, the amount of drift depends mainly on the quality of the recorders, My Tascams drift about 5 frames/hr, my old Zoom is about 1 sec/hr. My two Sony cameras are within a frame/hr.

Report · Nov 18, 2016

not very experienced.
using an Ipad to capture the audio.

Correct that.

B&H Photo Video

Report · Nov 19, 2016

I was a bit rushed when I typed this out.

I meant to state that I'm using an ipad and sometimes an iphone for capturing the video and simply a crude audio file that I then use to sync my other two, separate audio files that are both recorded using Rodelink Wireless microphone systems as separate audio files.

I don't have a lot of money, but I figured I'd lean more towards investing in the audio equipment and some other accessories for now and pair that with video from my iphone and ipad since they both shoot, to my understanding, fairly nice video for what I'm trying to record, namely some demonstration videos and interviews.

My issue so far is that I wasn't anticipating that even after I align the audio files and then switch them out for the original crude file, that the video file, though aligned at the beginning of the video to sync perfect, as the video proceeds, it begins to stray. Leading me to assume that somehow the timeline or length of one is longer or otherwise modified.

It's been suggested by others commenting on this to use Handrake to change the files to constant frame rate, which I've attempted, but unfortunately the video and audio still diverge. Frustrating to say the least. Perhaps it's another issue altogether. Admittedly, as stated before I'm not very experienced, but there is only one way to gain experience and that is trough trying, to good old trial and error method and learning from others with experience such as yourself.

If you have any thoughts, I'd certainly appreciate them.