Topic: synch sbd audio to dvd

[pepper]

Not sure if this is in the right section,but heres my question.


Im going to be seing a band next year and il be filming them.What i need to know is does anyone have the skill of synching audio from a sound board recording to a dvd.I was speaking to the guitarist of the band who's idea it was to do this,but i dont know what im doing with this kind of project.Anyone able to help??.

[stevetoney]

It's really simple.  The biggest thing needed is the right software. 

There are three software packages that I've used that would accomplish the video portion of the task; DVD Lab Pro, Sony Vegas, and Adobe Premier.  There are I'm sure many others out there, but these are the three that I know of...DVD Lab Pro is easiest to understand and use, followed by Vegas and then Premier.  I think it's probably safe to say that DVD Lab Pro gives really nice results, but maybe less 'professional grade' than the other two packages.

OK, next question is whether or not the video is a multiple camera video.  If it's just a single camera shot video, then this job is even simpler.  If you're doing a multi-cam, it's not all that much more difficult, but just requires more steps. 

(For a single cam video, I'd recommend using DVD Lab Pro since it's so dang easy to do.  This is the software that I use most, so I'm most familiar with it.  I'd have to beleive that the others are just about as easy to use as DVD Lab Pro for such a basic job.  If I have a multi-cam video to make, I do the video editing in Vegas....DVD Lab Pro really isn't made for that task.)

So, here's what you do with a single cam video. 

1)  Use DVDLab, Vegas or Premier to strip the audio from the video (called Demuxing or DEMUltipleXing).  After demuxing, you should have three files, the original mpeg video file, a .mpv video only file, and a .wav audio only file.

2)  Open the stripped audio in an audio mastering software program, such as Adobe Audition, Wavelab, or Soundforge. 

3)  Open the SBD file in the audio mastering software.

4)  Using the stripped audio as a basis, make the SBD file timing exactly the same as the stripped audio file.  Here's how I do this...

a)  First I go through both files and compare them to see if there are any major differences between the two files, such as drop-outs, early starts, late cuts, stoppages during the encore break, etc.

b)  Compare the timing of the two files to determine if the SBD needs to be stretched or shrunk to match.  I do this by choosing a continuous run of music that exists on both the SBD and the stripped audio.  I then select two distinct points in the music (usually a drum hit) at the beginning and end of the sample (the longer the sample the better).  Use the software to shrink or stretch the SBD audio to match the stripped audio.

c)  The goal is the match the SBD audio to exactly parallel the stripped audio, therefore, any dropouts (hopefully none) on the stripped audio need to be also made on the SBD audio. 

d)   I've had some instances where there was a drop-out in the video and I decided to leave the SBD audio intact and add space in the video rather than forcing the drop-out into the master video.   I do this by inserting either supplemental video (it might not match, but it's better than watching nothing while listening to the SBD audio) or I insert a slide show of some kind...either screenshots of the same video or stills of the band from either that show or another.

e)   Don't forget that after getting everything snynched up right, you also want to make sure that the end of the SBD file is also at the same spot as the end of the stripped audio...so that your master audio exactly matches the length of the master video.

4)   Once you get the two audio files to match exactly, you no longer need the audio file that was originally stripped, although I wouldn't trash it just yet.  Remux the SBD audio with the video file. 

5)   After the remuxing is completed, you will obviously want to check to make sure that the SBD audio synchs up with the video properly.  Check every several minutes throughout the video. 

6)   If the audio and video aren't properly synched, tweek the SBD audio file however necessary to fix the synching.  In my experience, the audio and video are usually well synched the first time, however I have had instances where I needed to tweek the master audio a little bit.  These include;

a)   shifting the start of the audio plus or minus a tenth or two to make the entire track synch properly (do this by adding or subtracting from the start of the SBD audio...usually all that's needed is a tenth or two.)
b)   doing another stretch/shrink if needed.

[tfs8271]

Tagging along for when this day comes....+t

[John Kary]

"b)  Compare the timing of the two files to determine if the SBD needs to be stretched or shrunk to match.  I do this by choosing a continuous run of music that exists on both the SBD and the stripped audio.  I then select two distinct points in the music (usually a drum hit) at the beginning and end of the sample (the longer the sample the better).  Use the software to shrink or stretch the SBD audio to match the stripped audio."

What process/application from above are you using to do this?  Could you walk us through how you're doing it?

[stantheman1976]

"b)  Compare the timing of the two files to determine if the SBD needs to be stretched or shrunk to match.  I do this by choosing a continuous run of music that exists on both the SBD and the stripped audio.  I then select two distinct points in the music (usually a drum hit) at the beginning and end of the sample (the longer the sample the better).  Use the software to shrink or stretch the SBD audio to match the stripped audio."

What process/application from above are you using to do this?  Could you walk us through how you're doing it?

This is EXTREMELY easy with Sony Vegas.  When you have the who tracks you need to find a spot at the beginning of the files to sync up at.  Drum hits are good or any distinct events where there is a quiet spot between events.  Zoom in and line your new SBD audio up with the beginning of the other audio and listen with headphones on.  When they are line up there should be no delay between the two sources.  It should sound like a single source playing.  Then go to the end of your SBD audio and see where it is in relation to your other track chances are it has drifted ahead or behind a bit.  Go to the very end of the SBD track and hold your mouse over the end.  Press the CTRL key and you'll see a "~" symbol appear.  The move your mouse left of right.  You are now shrinking or stretching teh whole track.  Adjust it accordingly until all points on both tracks are line up and sync.  For video don't freak out if your a frame off.  If you are deleting the original audio and using only the new source a frame or two won't be noticeable.  For mixing two audio only tracks they have to be lined up perfectly in all places.  Also, in Vegas go to Tools > Quantize to Frames.  Make sure that is unchecked.  If it is checked then when you stretch or shrink the track it will have to be a complete frame at a time.  If it's unchecked you can move the track any fraction you want.

[guitard]

For video don't freak out if your a frame off.  If you are deleting the original audio and using only the new source a frame or two won't be noticeable.

It all depends...

If it's a shot of someone strumming a guitar and singing...you might be able to get away with being off by two frames.  But other more precise things - like the drummer hitting the drums or a keyboard player hitting the keys - that'll noticeably be off.

[yousef]

I just upsample the separate audio recording to 48kHz, drop it into Vegas, line the start up with the audio that came from the camera and then time stretch it (click and drag the end of the file while holding ctrl) until everything syncs up. Sometimes I use Vegas's keyframing features to vary the level of the original camera audio from song to song or to give a bit of ambience between songs. Most of the time I just mute it completely.

This all works fine until the day you forget to turn the camera's external mic on... Fortunately, with 40dB of gain and some pretty severe EQ'ing there was just about enough audible to sync the SBD to. Eventually. Of course this was a multicam shoot where the two other cameras were only used intermittently or had completely overloaded the internal mic. 

The end result is looking quite acceptable. Not a mistake I ever intend to make again, though.

[stantheman1976]

For video don't freak out if your a frame off.  If you are deleting the original audio and using only the new source a frame or two won't be noticeable.

It all depends...

If it's a shot of someone strumming a guitar and singing...you might be able to get away with being off by two frames.  But other more precise things - like the drummer hitting the drums or a keyboard player hitting the keys - that'll noticeably be off.

I'm talking 1-2 frames.  When you're off by 1/30th of a second no person can tell.  I'm very precise on my projects but when you're starting out and trying it for the first time it's not going to hurt anything to be off by that tiny fraction.

[beatkilla]

When time stretching the clip in Vegas if you select the clip then press the 9 on numeric key pad you get a bracket or 7 for bracket at front end of clip.Then use your ctrl and mouse to get the squiggly line,use 1 and or 3 on numeric pad to stretch the clip 1 frame at a time.Press 5 to clear bracket.

[yousef]

When time stretching the clip in Vegas if you select the clip then press the 9 on numeric key pad you get a bracket or 7 for bracket at front end of clip.Then use your ctrl and mouse to get the squiggly line,use 1 and or 3 on numeric pad to stretch the clip 1 frame at a time.Press 5 to clear bracket.

Nice one - sounds like a useful tip...

One day I'll get round to reading the manual properly.

[willndmb]

i have never got the stretch/shrink method to work for me
it always distorts the sound, but maybe i am trying to big of a selection at once

at any rate
keep in mind, depending on how far away from the sound source you are that matching the audio from the board to the audio from the video doesn't always mean it will match the video picture
(usually if you are in the lawn or back of an arena)
the video will be ahead of the audio on the camera thus dubbing the sbd exactly to the audio of the camera will leave you with audio that doesn't match the mouth of the singer or drum hits or whatever

so before you start to dubb see if the audio is matched to the mouth or some other cue

[yousef]

i have never got the stretch/shrink method to work for me
it always distorts the sound, but maybe i am trying to big of a selection at once

I've done 1 hour+ without any noticable problems but I'm sure the amount you stretch by will also play a part in this...

That said, Vegas has an option hidden away on one of the menus that lets you select between high and low quality time-stretching options and I'm pretty sure that the default is 'low'.

[guitard]

For video don't freak out if your a frame off.  If you are deleting the original audio and using only the new source a frame or two won't be noticeable.

It all depends...

If it's a shot of someone strumming a guitar and singing...you might be able to get away with being off by two frames.  But other more precise things - like the drummer hitting the drums or a keyboard player hitting the keys - that'll noticeably be off.

I'm talking 1-2 frames.  When you're off by 1/30th of a second no person can tell.  I'm very precise on my projects but when you're starting out and trying it for the first time it's not going to hurt anything to be off by that tiny fraction.

I know you're talking about frames - and that's what I'm talking about.

Drop a clip into your NLE of a guy playing drums at normal speed and bump the audio over two frames.  It's very noticeable.

Going back to your previous post...I agree you can usually get away with something being off by one frame.  But as I stated in my previous post - if you're talking about two frames - that can be a different story.

Just my cent's worth...

[joel]

When time stretching the clip in Vegas if you select the clip then press the 9 on numeric key pad you get a bracket or 7 for bracket at front end of clip.Then use your ctrl and mouse to get the squiggly line,use 1 and or 3 on numeric pad to stretch the clip 1 frame at a time.Press 5 to clear bracket.

+T

been doin' a bit of video editing myself this week...got a dvd torrent going on digitalpanic:

http://digitalpanic.org/bittorrent/showthread.php?p=128666#post128666

stream it here:

http://video.google.com/videoplay?docid=-7317926137931835670&hl=en

edit to add my current project (streaming only)

http://video.google.com/videoplay?docid=-8069282673076983034&hl=en

[baustin]

b)  Compare the timing of the two files to determine if the SBD needs to be stretched or shrunk to match.  I do this by choosing a continuous run of music that exists on both the SBD and the stripped audio.  I then select two distinct points in the music (usually a drum hit) at the beginning and end of the sample (the longer the sample the better).  Use the software to shrink or stretch the SBD audio to match the stripped audio.

What about the situation where my audio source is definitely spot on (ie - taping audio with a 744t) and it may be the video that is drifting? Is it possible or wouldn't it be better to stretch the video rather than an audio source that is correct?