Strangest thing I've seen in ten years of Post

D

dougcabot

Member
I posted this mystery last week and got one response that didn't address the issue so I'm hoping that someone will find this worth trying to figure out this time.

Basically, I shot footage on MiniDV and the audio does the following:
1. Audio sounds okay in analog output -- ie. with DV deck hooked up to a monitor using RCA cables.
2. Audio sounds okay in Final Cut when running on a G4 Power Mac (eMac).
3. Same audio does NOT sound okay on the G4 eMac (or any Mac) when I play the linked Quicktime in the Capture Scratch folder, using Quicktime Player.
4. Same audio does NOT sound okay when played within Final Cut on an Intel machine.

Before anyone looks at 2 and 3 and says "That's impossible -- the source files are exactly the same; Final Cut uses the same QT files" -- I know. I am making no changes to the clip audio (or anything else) in Final Cut.

I'm used to performing all kinds of gyrations in the name of troubleshooting, and none of them are working. The latest? Use one DSR-11 deck to play the tape; send analog output to second DSR-11, which performs A-to-D conversion and records to a second MiniDV tape. Monitor second deck: sounds fine. Capture second tape to Final Cut on Intel machine: audio disappears.

Help me please!!! Thanks.
 
NoahK said:
What about it doesn't sound ok?

Noah
Click to expand...

Well -- the audio all but disappears, replaced with digital hiss, for lack of a better way of describing it. It sounds a little digitally stepped on when it sounds "okay" too, but the signal is there, and clear -- it's worlds different -- and that's the mystery. The same quicktime, played in one instance through FCP, and in the second instance using QT Player: totally different results.
 
This can happen when you accidentally record 12-bit 32Khz instead of 16-bit 48Khz audio on the camera. I'd try a recapture using the lower quality settings and see what happens.

Noah
 
NoahK said:
This can happen when you accidentally record 12-bit 32Khz instead of 16-bit 48Khz audio on the camera. I'd try a recapture using the lower quality settings and see what happens.

Noah
Click to expand...

I'm reasonably certain that the camera's audio settings were never changed from standard 48K 16-bit.

... not least because when I try to capture at any other setting I get the standard warning, "The audio sample rate of one or more of your captured media files does not match the sample rate on your source tape [etc]"

(By the way I can change FCP audio capture settings to 32K 16 bit but not 12-bit. Help?)

I also tried changing audio capture to 4 channels, just in case... but that didn't help.

Would anyone care to receive a 3MB one-second clip so you can experience some of this weirdness yourself? It is a clip that plays okay through both FCP and QT on a G4 but not on an Intel iMac -- no matter which machine actually does the capture. (You can email me at dougcabot[at]gmail if you don't want to publish your own address here.)

Is this one more clue? -- the one-second clip is different from the original full capture done on the G4, in these ways: the original capture quicktime appears to be a true 640x480 and the audio is two separate mono (Big Endian) 48K 16-bit tracks; whereas the one second clip is an export from FCE on the same G4, appears to be stretched to 720x480, and the audio is a single stereo track. Finally, as I said above, on a G4 the one-second exported clip plays fine in both QT and FCP but the original clip only plays fine in FCP --- not in QT, and not either way on the Intel iMac.
(The more I look into it, the more complex it gets.)

Thank you.
 
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Open it on the machine where it sounds OK in quicktime. Export another version out of quicktime. Send that new version to the intel machine. Work?

OR: out of quicktime (where it works)>export>select "audio to aiff">send that audio file to the intel, and drop it in your timeline.
 
I wish!

I wish!

ryan brown said:
Open it on the machine where it sounds OK in quicktime. Export another version out of quicktime. Send that new version to the intel machine. Work?

OR: out of quicktime (where it works)>export>select "audio to aiff">send that audio file to the intel, and drop it in your timeline.
Click to expand...

Neither idea works -- sounds just the same as with the full A/V clip.
(For what it's worth, the G4 eMac that i'm doing the export from is running FCExpress, not FCP actually, and does not have Quicktime Pro, so within QT Player all the export options are dimmed out. So I did the export from FCE.)

Thanks
 
Might be the original tapes have some kind of glitches on them. I'd try dubbing from DV to DV on another camera and see if that fixes the problem. Or run a head cleaner on your capture deck/camera and see if that makes a difference. If you still hear bad audio in the new captures that says to me the original tapes may have a problem.

Noah
 
have tried all that...

have tried all that...

NoahK said:
Might be the original tapes have some kind of glitches on them. I'd try dubbing from DV to DV on another camera and see if that fixes the problem. Or run a head cleaner on your capture deck/camera and see if that makes a difference. If you still hear bad audio in the new captures that says to me the original tapes may have a problem.

Noah
Click to expand...
Thanks for the suggestions but these are the kinds of things I tried before I posted here. I mean, I went as far as a full analog conversion: I dubbed to another tape using analog outs from one DSR-11 deck, and analog inputs in a second DSR-11, while monitoring audio from the second deck -- which sounded fine -- and the resulting footage STILL has the G4/Intel discrepancy. I'm telling you -- it's spooky.

Thanks!
 
Well I'm stumped but in general any time a DV tape's audio can't be captured it might mean bad tapes- i.e. dirty heads during recording. I'd take a tape to a professional dub house with an error correcting DV tape and have them make a digital clone.

Noah
 
dougcabot said:
Thanks for the suggestions but these are the kinds of things I tried before I posted here. I mean, I went as far as a full analog conversion: I dubbed to another tape using analog outs from one DSR-11 deck, and analog inputs in a second DSR-11, while monitoring audio from the second deck -- which sounded fine -- and the resulting footage STILL has the G4/Intel discrepancy. I'm telling you -- it's spooky.

Thanks!
Click to expand...

Just an odd thought, what codec are you using, and is there something 'different' about which codecs are used on the PPC vs the Intel Macs. As I recall there are audio options, like bit depth, representation (int or float), encoding PCM or not, etc.

I definitely have not had this sort of problem, but I've pretty much only done DV log and transfer in Final Cut Express, and now AVCHD L&T.

But I have seen clips that because I've not had the appropriate codec, I 'hear' the audio, but not the video. I've not experienced no/bad audio, and video fine... well at least that I can attribute to codec screwups...
 
the ultimate workaround

the ultimate workaround

j1clark@ucsd.edu said:
Just an odd thought, what codec are you using, and is there something 'different' about which codecs are used on the PPC vs the Intel Macs. As I recall there are audio options, like bit depth, representation (int or float), encoding PCM or not, etc.

I definitely have not had this sort of problem, but I've pretty much only done DV log and transfer in Final Cut Express, and now AVCHD L&T.

But I have seen clips that because I've not had the appropriate codec, I 'hear' the audio, but not the video. I've not experienced no/bad audio, and video fine... well at least that I can attribute to codec screwups...
Click to expand...
Pretty sure it's not a codec issue: I captured at straight up DV NTSC 48K.

The solution I have found is to go one step further with the analog pass-through. While it didn't work using a Sony DSR-11 deck, as I said in the last post, it occurred to me that a more "thorough" conversion would be to lay out the audio to an audio cassette deck -- which worked. Brought it back into the digital world using a Sony media converter (not trusting the DSR-11 at this point) and it works. Line up the audio, adjust for the sync speed difference, send it out to Soundtrack for noise reduction... and I'm back in business. Simple as that!

Still don't know what's wrong with those files and if anyone wants to look at a short clip, let me know.

Thanks all.
 
In a nutshell

In a nutshell

NoahK said:
Well I'm stumped but in general any time a DV tape's audio can't be captured it might mean bad tapes- i.e. dirty heads during recording. I'd take a tape to a professional dub house with an error correcting DV tape and have them make a digital clone.

Noah
Click to expand...
I'd be right with you and thanks for giving it thought Noah, but in parting I need to stress that the core issue is not that audio couldn't be captured, because it could. It's the fact that the captured audio could only be played back under limited (and weird) conditions: A) source quicktimes played back fine through FCE, but not in QT Player -- all provided that I'm using a G4 eMac; B) exporting same media from FCE (on the G4) produces quicktimes that play fine on the G4, both in QT Player and in FCE, but still will not play back audio on an Intel iMac. That's the weirdness in a nutshell. If anyone finds the answer, I might die happier, and I might not. In the meantime I have retired the old TRV-950 that produced this anomaly, and the problem has not recurred.
Thanks again.
 
I don't get it, but if you can get the audio to play fine on one system, there IS a way to make it happen. I'm assuming this is audio that you still need, so while it may not be the best option, it will at least make it usable. Since my first suggestion didn't work, I'd try this:

Essentially, what I'm getting at is RE-RECORDING the audio from the computer (where it plays fine).

Use a program like "Audio Hijack" or similar (I'm sure theres free software out there) that will record whatever is playing on your mac. Play the quicktime file, use that program to record and save the audio to whatever format you choose (audio hijack defaults to .aiff) I use audio hijack all the time to record something off of the net, and get surprisingly good results. Again, this is just under the assumption that you NEED to get that audio to play on the intel machine.

It'd be like playing it through the speakers on the good machine and recording the audio coming out of the speakers with a mic, except better quality. The file you end up with has nothing to do with the original as far as codecs/recording techniques, and it will play on any machine...

This whole thing sounds like a fluke incident to me, so I'd just get the audio like I recommended and move on...

-brown
 
dougcabot said:
Pretty sure it's not a codec issue: I captured at straight up DV NTSC 48K.

The solution I have found is to go one step further with the analog pass-through. While it didn't work using a Sony DSR-11 deck, as I said in the last post, it occurred to me that a more "thorough" conversion would be to lay out the audio to an audio cassette deck -- which worked. Brought it back into the digital world using a Sony media converter (not trusting the DSR-11 at this point) and it works. Line up the audio, adjust for the sync speed difference, send it out to Soundtrack for noise reduction... and I'm back in business. Simple as that!

Still don't know what's wrong with those files and if anyone wants to look at a short clip, let me know.

Thanks all.
Click to expand...

Have you tried exporting just the audio track as a WAV file (or AIFF), no compression, no nothing... then dropped that into the time line on the Intel machine?
 
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