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| rjisinspired |
| Posted: Jul 27 2010, 12:34 AM |
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I had been working on the Youtube/Google project and I am now deciding whether or not to continue with it because I have been on the computer since 5;30pm yesterday evening and I'm getting absolutely nowhere.
I used my digital 8 and brought along my Olympus DS30 audio recorder for substituting the audio from that to the camcorder audio. I timed the audio portion to fit the audio track recorded onto tape and also to the frame rate of the video and things work for about 60-90 seconds and then a drift in sync occurs. This is impossible since I have the audio matched to my mouth movements and the frame rate is matched exactly at 29.970fps. Technically I had been able to work with slightly long audio files to match videos and it would work out as long as the audio matched up with the video.
I'm working with uncompressed wavs also.
I have been at the computer since 5:30pm yesterday evening, I haven't been to bed yet and I'm still on the first segment trying to figure out why I have drift or latency issue. Sample rate for both audios match and the frame rate shows "29.970" in Vdub and yet I get a drift?
Doesn't audio get recorder at the same time on two different devices at the same time?
I have about 13 segments to align audio with video and I haven't even finished one of them yet and I started 27 hours ago.
The camcorder's audio track is bulletproofed. Filters and noise reduction don't seem to affect it much and when it does the results are terrible.
Reason why I recorded audio with an external device is because the rules stated "clear audio" In some scenes I was about 6-8 feet from the camera and you know how it is with motor noise being picked up and audio sounding like it's some distance away, my voice. The shots I did called for 3/4 body shots so I had to be some distance away from the lens.
If anybody has any suggestions on what I should do: Keep trying to prepare and align audio to the videos or to just use the existing track and dump quality out the window, please let me know. At this point I'm too tired to really care but when I wake up later I should be refreshed to make better decisions.
Thanks. |
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| phaeron |
| Posted: Jul 27 2010, 05:47 AM |
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The audio does get recorded on the devices at the same time... but it isn't always the exact same _amount_ of audio. Welcome to the wonderful world of "two clocks that don't count at exactly the same rate."
You've tried turning off the audio resampler in Timing > Capture Options? (That darn thing is squirrely.) |
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| rjisinspired |
| Posted: Jul 27 2010, 06:50 AM |
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The mismatch comes from importing an audio file over the existing audio track of the video. The capture itself went fine, A/V is in perfect sync. It's the "import audio from another file" is where I'm having the headache.
The imported audio was the same length and recorded from an Olympus DS30, converted to wav format so Vdub could import it.
The audio portions match up and this is noted at the start and in 60 seconds into the video where my voice matches perfectly with my mouth movements. It is after that time the drift starts up. The audio from the Olympus is 4:20:894, exactly what the video length comes out to be and under frame rate all values are exactly 29.970
In the past I had found that it was alright to use an audio file, imported audio file, that was slightly longer than the video, as long as it could be aligned then it would would work with constant drift. This isn't constant drift, it's gradual after 60 seconds.
I am extremely baffled about this. I cannot clean the existing audio from the video in Audition because it is either bulletproofed or even just the littlest of corrections produce major reverb/echo and/or harmonic artifacts in the audio.
I can only just keep the audio that I have and amplify it slightly, increasing the camera noise which is impossible to clean for, and just deal with that though the project people at Youtube request "clear audio" but unfortunately I cannot do that.
To give you an idea why I would like to replace the camera's audio track with the one made from the Olympus recorder, here is a sample:
First 15 seconds from the camera, Olympus after that
http://rjschat.dyndns.org:8080/auds/2010/0...Seg-cam-oly.mp3
I cut the audio from the Olympus good enough and it even matches by the sample and yet I'm getting drifts? This is a file? A friend of mine told me that what I have sounds like latency? I would expect something like this on the hardware level like with a USB headset and mic or an instrument, but on a file? Can't be latency since that would be right at the start. |
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| Jam One |
| Posted: Jul 27 2010, 01:47 PM |
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| QUOTE | | the audio from the Olympus good enough and it even matches by the sample |
Do you mean:
a) the LENGTH matches
b) the WAVEFORM matches
?
What would I do to synchronize A/V -->>
Save WAV from your CAMERA's footage.
Load it into Audition.
Load your Oly's audio into Audition.
Make sure the latter has the same nominal properties (Hz, bps) as the former.
Place file's windows with waveforms one under another; set the same % scale for both windows.
Tweak the latter to match the former looking at their WAVEFORMs.
Save&import the edited Oly's audio into VD. |
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| rjisinspired |
| Posted: Jul 27 2010, 07:17 PM |
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I backed up all the files onto DVDs.
Yes, "A" file length matches perfectly and "B", waveform was hard to derive since I was a distance away from the camera so the peaks were smaller. I had to go by the waveform of me coughing in some spots just to see those line up.
Did what you advised in audition, I don't know how many times, and both files from camera and Olympus match in length and the waveform peaks look like they line up but I still am hear a drifting which is confusing me even more.
Samples from camera audio: 8,016,673 samples
Samples from Olympus: 8,022,948 samples
????
Both files are 32Khz, 4:10.717 in length and match up with the video's frame rates in Vdub. I'm lost now. |
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| Jam One |
| Posted: Jul 27 2010, 07:35 PM |
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32Khz may be b.a.d. in some situations.
In certain cases, when you deal with hardware which has got fixed native sampling frequency of 48kHz you will inevitably have sync problems.
The safest way under such circumstances is to maintain 16bit stereo & 48kHz sampling frequency all the workflow long.
(This, particularly, means that even if your camera outputs mono signal you should capture it as stereo.) |
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| rjisinspired |
| Posted: Jul 28 2010, 06:26 AM |
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My digital 8 use to record 48Khz but now it only does 32. I hadn't changed anything for sound in the menu so it's always been on the "16 bit" audio setting. There is a 12 bit setting but I never had used it.
I thought maybe to upsample the camcorder audio and Olympus audio to 48Khz in Audition but this didn't fix anything.
Both my camera and Olympus are stereo. The Olympus recorder uses 44,100Khz at 128 rate, 16 bit. My camera use to do 48K but now does only 32Khz. I noticed that when the audio preview from the camcorder stopped working is when I noticed the loss of 48Khz audio. Resetting the camera back to the factory settings didn't correct anything in this regard.
I was able to work with the existing camera audio so things are going ok for now. |
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