Author Topic: How does Dxtory capture audio?  (Read 17496 times)

zerowalker

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Re: How does Dxtory capture audio?
« Reply #15 on: June 07, 2013, 04:56:44 am »
1 hour is to little to detect it on most cards.

The sync issues seems to be around 50ms per hour more or less, and either the audio goes to fast or to slow.

1 hour is to little to detect, and hard when you can't compare it, which you can't when you play games.
Which is why i recommend something that goes repeat all the time.

Cause if you really get NO sync issues at 5hours, then that is really something, and i have to try to understand why you don't get any sync issues.

De-M-oN

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Re: How does Dxtory capture audio?
« Reply #16 on: June 07, 2013, 05:04:10 am »
I'm pretty sure it is also with over 5 hours the case :P

But 5 hours is a little bit very time consuming  :-\

zerowalker

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Re: How does Dxtory capture audio?
« Reply #17 on: June 07, 2013, 05:09:01 am »
Hopefully it is, but i doubt it.
If it is, it would break what i have concluded;P

If you can have your PC on through when you sleep, please try and record Super Mario World,
It takes no space as it's 2D with Lagarith.

That's how i do it, as i would never record 5 hours of nothing just waiting;P

zerowalker

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Re: How does Dxtory capture audio?
« Reply #18 on: June 09, 2013, 12:00:06 am »
Exkoder,

Can i get a timing log option?
Cause as said, if i have a timing log, i will be able to get a precise number to sync, it will solve all my problems.

ExKoder

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Re: How does Dxtory capture audio?
« Reply #19 on: June 09, 2013, 01:36:51 am »
It will not solve the problem.
A special program is required in order to investigate.
Regrettably there is no excessive resource for carrying out the program development.

zerowalker

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Re: How does Dxtory capture audio?
« Reply #20 on: June 09, 2013, 01:40:03 am »
Why not?
If i can get the relative rate of the audio and video, it will be all i need to make it sync.

There is no need for a special program, all that´s needed is a log where it writes the frametimes and ms per byte for the audio.
Then the relative rate can be calculated and fixed:)

ExKoder

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Re: How does Dxtory capture audio?
« Reply #21 on: June 09, 2013, 02:04:30 am »
When it is an AVI file, it is a correct time stamp.
Even if it outputs a log, it will be equivalent to the time stamp calculated from AVI file.
For investigating what a cause is, special test is required.
I think that it is difficult to investigate this case since you are not an expert programer.

zerowalker

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Re: How does Dxtory capture audio?
« Reply #22 on: June 09, 2013, 02:09:09 am »
That depends.

If you output a log compare to how the sample and frametimes are recieved, than it will not be equal to the AVI timestamp.

As when the data is written, Dxtory assumes the AVI is correct, the Video and Audio is the same length also, which i guess comes from how it´s recorded.

Normally the Audio and Video will never be the same length over a long period of time. The audio will either grow shorter or longer then the Video, (if the recording isn't done by a single device and One sync clock).

I would like to know how you Dxtory manages to assume the sync?
Cause if you record with other softwares that does similar things, the audio and video will grow away from each other sooner or later.

Malix

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Re: How does Dxtory capture audio?
« Reply #23 on: June 22, 2013, 05:56:39 am »
Bump & resurrection of old thread

I just did a test recording out of curiosity, ~2hours of Nestopia (nes emulator)

Both video and audio tracks are the same length, but the audio starts to get delayed  quite a bit, roughly a half a second, at the end of the video.

edit:
recording settings were
60fps capture, lagarith (excessive, I know)
1 audio channel 44.1kHz, 16bit, stereo.

occasionally the recording fps dipped to 58fps, for whatever reason.

Going to make a new test with 30fps capture if the audio lags with that.
« Last Edit: June 22, 2013, 05:58:43 am by Malix »

zerowalker

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Re: How does Dxtory capture audio?
« Reply #24 on: June 22, 2013, 05:59:17 am »
There you go:)

I am not alone, the problem exists, and differs from PC to PC, depending on the clock.

It´s weird that they are the same duration though, that has something to do with how Dxtory capture, or handles the streams, as normally, the audio stream and video stream are independent, and should be as long as it takes. But of course if they are in sync, they should be very close to each other.

Malix

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Re: How does Dxtory capture audio?
« Reply #25 on: June 22, 2013, 06:26:18 am »
Actually, I take that back, audio and video are NOT the same length.

zerowalker

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Re: How does Dxtory capture audio?
« Reply #26 on: June 22, 2013, 06:28:44 am »
Hmm, very weird.
What does it say if you open the video, and check the wave file (tell me the duration of the video file, and the wave file).

De-M-oN

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Re: How does Dxtory capture audio?
« Reply #27 on: June 22, 2013, 06:37:18 am »
Just remove the too long audio part so that it is exactly at the .xxx ms same length as the video is.

Malix

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Re: How does Dxtory capture audio?
« Reply #28 on: June 22, 2013, 06:40:11 am »
Just remove the too long audio part so that it is exactly at the .xxx ms same length as the video is.
doesn't change the fact that the audiosync is way off.

zerowalker

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Re: How does Dxtory capture audio?
« Reply #29 on: June 22, 2013, 06:40:46 am »
If he removes it, it will still be desynced, he will have to stretch it, but making it the same length at video won´t make the sync precise, however it will probably be close.