MiniDV Audio Problem - Please Help !

kimandfil wrote on 8/19/2007, 7:25 PM
I realize this is a forum for editing questions, but I was hoping someone could help me resolve an audio problem I’m having with some of my miniDV tapes.

I had an old Canon miniDV camera that started giving me some audio and/or video problems. After looking into the cost for repairs, I decided to replace it. I’m working on a project now and I’m capturing some tapes from several months ago when I was using my old Canon camera. When I first noticed some imperfect audio and/or video, I said to myself “this must be from the Canon”. However, I’m noticing an awful lot of video that has very “scrambled” audio. Almost like I’m hearing about one good word out of every ten. The rest of the time it is just a scrambled mess !

I noticed a scene that I had previously captured a few months ago. At that time, both the audio and video of the scene was perfect. Now I’m capturing that entire tape and now I notice that the previously perfect video clip is not all but useless.

How could the tape be perfect a few months ago and now be complete garbage ? The tape has been stored in a low humidity, cool environment. Hasn’t been near any magnetic objects. I tried cleaning the heads of my new camera, but that didn’t help.

I’m working on a project for my son’s 7th B-Day party and there are some great scenes, but now the audio is completely destroyed.

Would appreciate any thoughts. Thanks !

Comments

kimandfil wrote on 8/19/2007, 8:14 PM
As if I wasn't already confused enough . . . . . . . .

Just for "kicks" I tried using my old Canon camera to capture from the tape. The audio sounds great ! !

So I have a miniDV tape that has been captured using two cameras.
New Panasonic GS-320 = audio is awful
Old Canon Optura PI = audio is great

Is there something "special" about the way Canon records audio that Panasonic cannot understand ? ! I haven't done enough research to know if ALL of the old Canon tapes sound this way on my new Panasonic, or if it is only SOME tapes.

Anyway, at least I'm a little encouraged that I can now get some good audio for my project.

Anyone know what's going on ?
Ivan Lietaert wrote on 8/19/2007, 10:10 PM
First this: is the audio bad in preview, or is it bad in the finalized, rendered file? To find out, render a small portion of video with bad audio and listen to the result.
If it is bad in preview only, then you can leave it as it is, or you could go to 'preferences', audio device tab and crank up the 'playback buffering (seconds)' (mine is at 0.53) until your sound is ok.

Second, how do you capture the tape? Use the Vegas Capture program only, as this can also affect the audio quality.

Third, I have a Canon camcorder. I know the audio has two settings: 12 bit and 16bit. Something similar may be at the root of your problems.
kimandfil wrote on 8/20/2007, 4:27 AM
Hello Ivan123 -

Thanks for your thoughts.

The audio is bad when played on the Panasonic camera and bad in preview. I have not rendered anything from the project yet.

The only thing I have used for capture is the VMS Capture utility.

The audio setting on the tapes recorded with the Canon camera was 12 bit.

I guess the thing that really confuses me is that the tape sounds great when captured with the Canon, but is completely destroyed when using the Panasonic.

After I capture all of the previously Canon recorded tapes, I'll be strictly using the Panasonic. Any tape I have recorded with the Panasonic, plays back fine on the Panasonic.

For some reason, the audio that was recorded on the tape by the Canon is not able to be "read" by the Panasonic. Isn't miniDV format a "standard" ? It doesn't vary from one manufacturer to another, does it ?

Thanks again for your help !
Ivan Lietaert wrote on 8/20/2007, 4:35 AM
MInidv is a standard, yes, but only the cassette hardware. How video and audio is transferred to the tape is a whole other game. One user even said he could only use sony minidv cassettes, so where is the standard then? But I'm sure you should avoid using different camera's for playback. I also read somewhere there is Type 1 and Type 2, but my knowledge ends there.
You should really render a portion - 30 seconds will do - to find out if the bad sound is also present in the rendered video.
kimandfil wrote on 8/20/2007, 5:33 AM
Hi Ivan123 -

I did not realize that the miniDV standard applied only to the cassette hardware. I was under the impression that the way the audio and video were recorded was also a standard. The fact that it is not, that explains a lot of why the audio is different when played from different cameras.

I will try rendering a small portion just to see how the "finished" product sounds.

I knew that my old Canon had recorded some bad audio and/or video on a couple of tapes, but it just seemed like I was seeing bad audio on tape after tape after tape after tape. Something seemed wrong. When I heard bad audio from a clip that previously had perfect audio, I knew something was up.

Thanks again Ivan, I really appreciate your help !
4eyes wrote on 8/20/2007, 10:10 AM
I would first eliminate any camcorder problems:
With the new Panasonic camcorder NOT connected to your computer you should be able to playback the tape that was recorded in the Canon camcorder. Even connect the pana cam to a TV. You can preview the sound as is on the panasonic camcorder.

If the sound is still wrong playing back using the panasonic's internal speaker or audio output to a TV then of course it's the cam. If not then something different with the panasonics firewire communication. You should use only firewire and not usb for capturing dv if possible. New cams can capture full dv using the usb2 connection with the 2 installed drivers. So if using usb then switch to firewire cable.

If the panasonic still plays the tape back incorrectly by itself (not connected to the computer) then take a look in the panasonic's setup menu under the audio settings. When tapes are recorded in 12bit mode the cams will use 4 tracks (2stereo tracks). There are audio settings how to handle these 2 tracks, MIX, Sound1, Sound2. So I would change the default settings from Mix to Channel1 first.
The canon units were reported to have a descent amount of background & motor noise. Could be this noise is on the 2nd stereo audio track and if the cams audio setup is set to MIX the channels your hearing the 2nd audio channel. Or, somehow you originally recorded the audio on the 2nd channel which then change the audio mixer to Channel 2.

Just some possibilities, hope they help but I would first take a look at your audio mixer settings in the new panasonic camcorder.
Also, under VMS audio properties change your "Project Properties" (File | Project Properties) to DV and on the audio tab I would change these settings to 12bit, 32khz as the audio settings because thats what is on the cam if you recorded in 12 audio mode. This way your Project Properties are equal to your source video properties.
kimandfil wrote on 8/20/2007, 10:25 AM
Thanks 4eyes for your suggestions.

When playing the tape on the Panasonic not connected to the PC, I still have the bad audio through the cameras internal speaker. I have not tried it connected to the TV. Tapes that were recorded by the Panasonic play back perfectly on the Panasonic.

When I decided to replace my old Canon with the new Panasonic, I looked into having the Canon repaired. Based on the symptoms, I was told it was likely a misaligned head issue.

I submitted this question on another internet forum and someone mentioned that maybe the reason one camera produces good audio and the other camera produces bad audio is that maybe one of the cameras has a misalignment problem.

So I'm wondering . . . . . if in fact my old Canon has a misalignment problem, that means my old tapes were recorded with these misaligned heads. Does that imply that I would need those same misaligned heads to properly play back the tape ? If the tape was played back on correctly aligned heads, would it have a problem, like what I see when played back on the new Panasonic ? I'm assuming the Panasonic heads are aligned properly.

Might seem like a reaonable theory to me. Maybe ? ? ?

Thanks again for your help !
MSmart wrote on 8/20/2007, 12:14 PM
if in fact my old Canon has a misalignment problem, that means my old tapes were recorded with these misaligned heads. Does that imply that I would need those same misaligned heads to properly play back the tape ?

Yes, that's exactly what you need to do.

This would be very similar to problems people experience when trying to playback tapes recorded in EP mode on a different brand camera than it was recorded with. If I remember correctly, SP is a standard that manufacturers must follow specs but EP more loosely defined. I've heard of people having problems trying to read EP recorded tapes in a different brand camera but when using a different camera of the same brand, it worked fine. Then again this information could have been applied to VHS-C cameras rather than MiniDV.

Regardless though, you're going to need to keep your Canon to use it for playing back/capturing tapes it recorded.
kimandfil wrote on 8/20/2007, 12:44 PM
Thanks MSmart, I appreciate your comments !

The one thing that might complicate this is that I'm sure the misalignment problem has happened slowly over time. Some of the first tapes I recorded with the Canon several years ago when the camera was new were recorded with properly aligned heads. I'm guessing these might play properly using my new camera (although I haven't tried this).

Obviously the most recent tapes recorded with the Canon will need the same misaligned heads to play back properly.

The tricky part would be the tapes in between. A tape from 2-3 yrs ago, might play OK in the Canon ? might not ?

Obviously I need to get the video from tape into my PC while I still have the means to play the tapes properly.

When I purchased my new camera, I wanted to get a miniDV camera because I had so many tapes from the past. I also liked the miniDV format because of the higher data rate. But issues like this make me wonder if a hard-disc based camera wouldn't be the way to go ? I have not compared the video quality of a finished product between miniDV and hard-disc formats.

Trying to keep various cameras to use with various tapes because of unique characteristics of the camera when the tape was recorded could become a real nightmare !

Oh well, at least I have a way to get some reasonable audio for my current project.

Thanks again, I really appreciate your help !
Ivan Lietaert wrote on 8/20/2007, 2:21 PM
For the record: in minidv format, the sp format is standard, the others modes (lp, elp etc) are much less of a standard and vary depending on the brand. Were your Canon tapes shot in sp mode?
Second, mixing different brands of tape may give problems: the different lubricants used may chemically react and make the heads dirty. Yet, this thesis is contested as it may have been brought to life by tape manufacturers (esp. Sony!).
The out of line heads is imho the most plausible thesis.

Edit: from Wikipedia: "DV on SP has a helical scan track width of 10 micrometres, while EP uses a track width of only 6.7 micrometres. Since the tolerances are much tighter, the recorded tape may not play back properly or at all on other devices."
4eyes wrote on 8/20/2007, 3:04 PM
On your new panasonic unit most users would agree to make 16bit or 48khz the default dv audio setting when you shoot new footage. This is the same audio format for making a dvd and seems to produce less problems on the audio side when editing. 16bit-48khz Stereo is also higher quality, less noise & nice for music events.

I'm curious if you played with the audio mixer settings in the audio setup on the panasonic unit.
If you record in 16bit,48khz mode the cams audio mixer settings don't apply because there's only 1 stereo track recorded on the tape. These audio mixer settings only apply to the audio on the dv tape when recorded at 12bit, 32khz.

To confirm the Canon's heads being a problem. You can use a test tape & record some video on the canon, then play it back on the new panasonic unit.
If there is a head alignment problem with the Canon you will need to get the information off the dv tapes used by the Canon before having the unit serviced. But using a test tape will confirm this.
I would also check the settings in the Canon unit, normally my settings are 16bit - 48kz SP (standard play). Double check the Canon unit is set to these values for any future recordings on the Canon.

Sometimes using a cams reset button or under the setup menu "Reset/Load default settings" can correct/fix a cam. Worth a try, usually not worth the cost of having them repaired.
kimandfil wrote on 8/21/2007, 8:29 AM
Thanks guys for your comments !

Ivan123 -

All of the Canon tapes were recorded in SP mode. I have always used SP mode. Shortly after purchasing my first camcorder, several people recommended not to mix tape brands. I have been using the same tape for the past several years. Both good points, I appreciate your help !


4eyes -

Both my old Canon and new Panasonic have recorded in 12 bit audio. Thanks for your suggestion, I'll switch to 16 bit audio in the Panasonic immediately. Would it be OK to make this change when I'm part-way through a tape ? Or should I wait until I start a new tape ? I have not played with any of the audio settings on the Panasonic.


Last night I re-captured one of the "bad audio" tapes using my old Canon, and things sound fine now. Hopefully this gives me a means to get some audio where I can at least understand the words.

Thanks guys for your help ! I appreciate all of your suggestions !
MSmart wrote on 8/21/2007, 9:11 AM
Would it be OK to make this change when I'm part-way through a tape ?

Yes, you can change it.
kimandfil wrote on 8/21/2007, 9:53 AM
Thanks MSmart !

I appreciate your help !
routerguy99 wrote on 8/21/2007, 9:54 AM
I made the same mistake when I first received my Panasonic, I ended up making a change to my audio as well as swiping out my Tape.

Chris
4eyes wrote on 8/21/2007, 12:03 PM
Would it be OK to make this change when I'm part-way through a tape ? I've never done this. If recording on a dv tape you start with 12bit audio and change to 16bit in the middle of the tape will VMS split the captures? I've heard where other programs may have a problem trying to capture the whole tape then. I've never done this, always recorded the audio at 16bit 48khz.
4eyes wrote on 8/21/2007, 12:03 PM
Would it be OK to make this change when I'm part-way through a tape ? I've never done this. If recording on a dv tape you start with 12bit audio and change to 16bit in the middle of the tape will VMS split the captures? I've heard where other programs may have a problem trying to capture the whole tape then. I've never done this, always recorded the audio at 16bit 48khz.
kimandfil wrote on 8/21/2007, 12:25 PM
Thanks 4eyes -

I'm near the end of the tape I'm currently using, so I think I'll wait until I start a new tape.

If I understand the audio settings correctly, 12 bit is useful if you want to add other audio from another source onto the tape. 16 bit would give you better audio, but does not give you the option of including audio from another source.

Is this correct ? If so, it makes perfect sense for me to be recording at 16 bit. I have never considered including audio from another source.

Thanks again for your help !
4eyes wrote on 8/21/2007, 12:39 PM
Yes, the 16bit setting to me is better. If you record in 12bit-32khz the audio has to be converted to 16bit-48khz for creating a dvd anyway because 16bit-48khz is the dvd specification for audio. So in the end the audio on a dvd will be 16bit-48khz in either 3 formats (lpcm.mpeg or dolby), but the audio spec's will still be 16bit-48khz. Mpeg or Dolby audio is compressed so it's better to use Dolby on a dvd which in turn will allow more space on the dvd for higher quality video. So when using DVDA I always use Dolby 2/0 or 5.1.
You can always add audio tracks for overlays in VMS anyway. Different uses for different users.
When I get time I'll mix a test tape to see how VMS handles the capture with mixed audio. I would think the program would have to split the capture into a 2nd file.
kimandfil wrote on 8/21/2007, 1:13 PM
Thanks 4eyes !

Thanks for the education regarding audio settings. I have not played with any audio settings. Next time I burn a DVD, I'll use your suggestions for DVDA.

When I mentioned using audio from another source, I meant another source connected to the camera. Obviously in VMS, I can add audio from many sources. Now that I think about it, I'm ashamed that I've always used 12 bit. WHAT WAS I THINKING ? !

Thanks again for all your comments ! You've been a big help !
kimandfil wrote on 8/21/2007, 2:01 PM
Since I've had to go back and re-capture some tapes with my old Canon camera, I've noticed something a little curious and was hoping someone could explain it.

When I initially captured the tape I would end up with, say 20 clips. Each clip had the base name of, say Tape 001. So I have 20 files named Tape001 - Clip01.avi, Tape 001 - Clip02.avi, . . . etc.

When I realized I needed to re-capture this tape, I deleted all of the previously captured clips and started with a completely emply folder. When I re-captured the tape, the clip numbering starts at 21, instead of 1. The numbering is continuing from where the previous set of captured clips ended. The previously captured clips are not there any more, so how does VMS know to start the new captured clips at 21 ?

Is there a setting somewhere in the capture utility that controls this ? It's a little spooky that VMS recognizes the earlier clips, even though they're not there !

Would appreciate any thoughts. Thanks !