Chris Sweet
April 23rd, 2008, 05:09 PM
Am I stuck either plugging audio into the camera direct, or syncing by hand in post?
Or is there any way to sync to an audio recorder without the timecode ports (external device? FW->BNC? exist?)
Thanks!
Bill Pryor
April 23rd, 2008, 05:45 PM
There's no way to get timecode out of the XH A1 for that purpose. You'd need to buy the XH G1, and that's one big reason it's $3K more. And you'd have to have a sound recorder with sync capability.
You could do it the way we shot sync sound for many years back in my 16mm film days: use a slate and clapboard. Actually, I still use the old clapboard when syncing a video camera with a sound recorder, so that's not as obsolete as people might think. You just have to be sure the camera mic is on, and to do the clapboard about equal distance from the soundman's mic and the camera mic, otherwise you could end up up to a frame out of sync if the room's big enough.
Chris Sweet
April 23rd, 2008, 07:23 PM
cool thanks for the help. I've been doing location sound work for the past year and a half, and have tc capabilities on my recorder. Been doing editing and post work for a few months now as well. So I'm too much of a noob to have worked in the days of analog slates. lol. On the last proj I worked on though, the onboard mic was turned off on the A1. I told him to so there'd be no chance of that crappy audio being used. I guess if it was left on, lining up the waveforms would be how to sync.. is this what you mean?
On this post work I'm doing there is no tc, and no audio on the camera. Is there a difference in time, from when the lens picks up the slate shutting in front of the camera, to the mic recording the clap about 7-8 feet away? Would this method of syncing be hard to get accurate?
thanks again for any help
chris
cheers
Steve House
April 24th, 2008, 04:18 AM
cool thanks for the help. I've been doing location sound work for the past year and a half, and have tc capabilities on my recorder. Been doing editing and post work for a few months now as well. So I'm too much of a noob to have worked in the days of analog slates. lol. On the last proj I worked on though, the onboard mic was turned off on the A1. I told him to so there'd be no chance of that crappy audio being used. I guess if it was left on, lining up the waveforms would be how to sync.. is this what you mean?
On this post work I'm doing there is no tc, and no audio on the camera. Is there a difference in time, from when the lens picks up the slate shutting in front of the camera, to the mic recording the clap about 7-8 feet away? Would this method of syncing be hard to get accurate?
thanks again for any help
chris
cheers
Sound travels at about 1 foot per millisecond, so the clap of a slate 8 feet away will be delayed about 8ms or between 1/3 and 1/4 frame.
In a film workflow where the audio is resolved to analog media or audio and video are mated in telecine, timecode controlled the speed of the process and provided not only lineup but maintained sync over the duration of the reel. But with a video workflow, all it does is provide a single lineup point to aid in establishing sync plus provides a system for logging and cataloging shots. It doesn't do anything to maintain sync as the shot plays out - for that you need to salve wordclock or blackburst so the samples clocks are locked together. While it would be convenient to have the camera and audio timecodes the same, you can achieve the same lineup point by using a smart slate that has been jammed from the timcode generator in the audio recorder, displaying the timecode values in the audio at the instant the slate is clapped. OF course that means the audio recorder has to generate and output timecode, not just read it ... the Sound Devices recorders do but the popular Tascam HD-P2 only reads external timecode and doesn't gene4rate any for output.
Chris Sweet
April 24th, 2008, 06:34 PM
great thanks for those details! I will convince the producer to rent a digital slate next time a camera like the A1 is being used.
cheers
Don Palomaki
April 25th, 2008, 06:12 AM
A clap board, or similar impulse noise maker, at the talent (sound source) is probably the simplest method and it preserves the relative lag between light and sound at the camcorder. You sync on the audio waveform. If the camcorder (viewers eye) is ~35 feet from the talent, you expect the sound to arrive about one frame after the video.