Audio syncing question.....

[Nick Castronuova]

I'm looking to purchase the Panasonic GH-1, the only drawback is that it does not have a headphone jack or very much audio control (though you can attach an external mic).

 

I'm considering purchasing it along with a flash recorder/external mics. The camera shoots at 24p, should I have trouble syncing my audio? It's just like syncing film dailies, right? There shouldn't be any drop-offs in the 24p signal (like when shooting with older film cameras), right?

 

Now, for the basic film student audio question, does it matter if your camera is running at 24 fps or 30 fps when recording on a flash recorder?

[Adrian Sierkowski]

Same as with film, or any double system. Does the recorder not have a 24fps setting?

[Nick Castronuova]

No, it has htz settings.

[Ian Kirton]

You may be interested in ths software http://www.singularsoftware.com/pluraleyes.html. It's a plugin for most of the popular editing software and will automatically sync audio to picture.

[Matthew Freed]

Bit depth, sampling frequency, and frame rate are three completely different things. Bit depth (16 bit or 24 bit) gives you dynamic range of your audio. Think of it like how clear your blacks are on a video camera. The higher the bit depth the more dynamic range you can record (which is a good thing). The sampling rate is how many times per second the audio recorder snaps a "picture" of the analog sin wave. The higher the sampling rate the more accurate the audio recording. Music recording is standard at 44.1khz or 88.2khz. Audio for picture is at 48K or 96K, sometimes up to 192k. the Nyquist theory states that sampling rate must be twice that of the highest desired audio frequency to be captures. So, if you want to record an audio signal at 20Khz then you have to sample it at 40khz, minimum.

 

Frame rate on your audio recorder must be set to the same rate as your camera. So, if you're shooting 24 fps on film then set your audio recorder to 24 fps. If you're shooting 24p on video then set your audio recorder to 23.976 fps (it has to do with the digital conversion of the picture and I don't fully understand this). If you're shooting at 30 fps film, set your audio recorder to 30 fps (either drop or non drop depending on the camera settings). Same with video. 29.97 for video.

 

There are no prosumer cameras on the market that adequately record audio. The circuitry is very poor and is generally an after thought. After all, they are tools for recording pictures, not audio. An audio recorder will yield higher sound quality and more control over the audio signal.

[John Sprung]

Syncing 24 fps picture with 30 Hz sound is done all the time in the professional world. It's pretty much standard operating proceedure. With consumer equipment and editing systems, you need to test the actual setup you propose to use.

 

One thing to watch out for is that they may say 24, but actually deliver 23.976. Which is fine if the audio recorder also actually gives you 29.97. The test to do is to shoot a long take with both head and tail sticks. Getting the "point nine something" vs. "point zero zero" thing wrong will cause a sync error of one frame in about 42 seconds, so run the test for a few minutes to be sure of detecting it.

 

 

 

 

-- J.S.

[Martin Hong]

What I have been doing is sync the audio on the editing software, you can try to match the waveform from both audio files, it does not match perfectly because the video was recorded in 23.976 while the audio was recorded in 0:00:000 format, so you dont have a perfect match. However, I never had problem synchronizing them, they still match and theres no big difference.. at least from my experience. Because i never needed more accurate sync...