Recorded audio starts before zero

[danroush]

I just re-installed Windows XP, thanks to a virus, but now my new copy of Audacity isn't functioning like the old one did.

XP SP1 and Audacity 1.2.6.
When I record audio from a digital voice recorder, it works fine, it's just that the recording starts at about -8500 samples. This is annoying because I delete the beginning and ending of each file, and export the middle of it to a *.wav file.
Now I have to first align the track with zero, then delete the beginning and ending data points.

I know that extra step sounds ridiculous, but I'm obsessive compulsive about it. I usually record multiple tracks at a time.

[kozikowski]

<<<from a digital voice recorder>>>

Does that count in some way? Are you transferring digital bitstreams?

This could be messy. I think you should blow your install away, download and install a fresh one. However, Windows doesn't let you nuke the Audacity Preferences file like the Macs do. You could go through all that and find yourself right back to your old settings.

For the record, are you using 24-bit sound?

This is part of a preferences thread from a little while ago.

http://www.audacityteam.org/forum/viewt ... 463#p17378

Koz

[danroush]

No, the DVR doesn't make a difference. I used it before I had the virus with no problems.

I re-installed my sound card, then uninstalled Audacity.

I notice if I start recording at say 3000 samples, it will shift the audio back to start at about 150 samples.
I assume it is starting at zero, but getting pushed back for whatever reason.

I'll try 1.3.5 beta. It appears to work fine in 1.3.5. I'm not sure what the cause was, but it's solved.

[steve]

Try uninstalling Audacity, then deleting the Audacity registry entries at HKEY_CURRENT_USERSoftwareAudacity then reinstall Audacity.

Alternatively try Audacity 1.3.5 (this version does not use the registry).

If you are not confident about editing the registry, use the second method.

[Gale Andrews]

I'm not sure why we're discussing 1.2.6 Preferences in the context of latency correction as there is nothing in those preferences that controls it, only in 1.3.5 Preferences.

1.2.6 relies on the automatic latency correction in PortAudio v18 (our audio input/output library). For most people this works quite well (it calculates latency on my system at about 100 milliseconds (ms) - close to the 120 ms it normally is). Armed with PortAudio's calculation, Audacity then physically drags the track back that much after recording stops. The 1.3.x Beta series uses the later PortAudio v19 and its latency correction previously worked poorly, so much so that we disabled it in 1.3.4 (hence many complaints that latency correction no longer worked).

After updating PortAudio v19 and testing it, we re-enabled its latency correction in 1.3.5. However if it does not get correction right, then add a correction figure at "latency correction" in the Audio I/O Preferences (a positive value will drag the track forwards after recording, but no need to put "+" in front of the value).

I wrote some basic help on navigating/locating/resetting Preferences recently on the Wiki:
http://audacityteam.org/wiki/index.php? ... references

I didn't actually know the correct path on Mac for 1.2 Preferences, however I'll grab this from Koz's other post:
/SystemDrive/Users/Me/Library/Preferences/audacity Preferences

and add it to the Wiki article.


Gale

[steve]

@ GaleAndrews - Could I ask for a little clarification here.

In Audacity 1.2.6, latency correction is calculated rather than just using a default value?
Is this calculated value stored anywhere (in the registry?) or is it calculated each time Audacity starts?

Re. latency correction in Audacity 1.3.4 - I've got Audacity ® 1.3.4-beta (Unicode), Program build date: Nov 5 2007, running on Windows XP, and the "About" help item says that it uses PortAudio v19 and latency correction works brilliantly. Audacity starts with a default value of 0 (zero), which can then be adjusted manually to provide very accurate adjustment (to within just a few samples).

[Gale Andrews]

@ GaleAndrews - Could I ask for a little clarification here.
In Audacity 1.2.6, latency correction is calculated rather than just using a default value?
Is this calculated value stored anywhere (in the registry?) or is it calculated each time Audacity starts?

As I understand it, the value is calculated (not a default value), but definitely no latency information is stored in the registry, so messing with the 1.2.6 preferences or deleting them won't change latency behaviour. My knowledge of what exactly happens is pretty much limited to what I stated, but I suspect the value is indeed calculated when Audacity queries the available sound devices at start up, then stored internally. The point is therefore that there is no way users can change latency correction in 1.2.6.

Re. latency correction in Audacity 1.3.4 - I've got Audacity ® 1.3.4-beta (Unicode), Program build date: Nov 5 2007, running on Windows XP, and the "About" help item says that it uses PortAudio v19 and latency correction works brilliantly. Audacity starts with a default value of 0 (zero), which can then be adjusted manually to provide very accurate adjustment (to within just a few samples).

Exactly - in 1.3.4 there is only a *manual* adjustment which the user can make in the Preferences. If you do not enter a value in the "Latency Correction" box, there will be no correction and the recorded track will stay where it is. But if you calculate the amount you need to drag the recorded track backwards into sync, enter it in "Latency Correction" and then the system is consistent in always producing the same latency, that manual correction will appear to work perfectly.

In 1.3.5, an *automatic* correction is applied by PortAudio, This means that even if you leave the "Latency Correction" setting in Preferences at its default of zero, the recorded track will be pushed backwards by the amount of the automatic correction (if of course you have more than one track on screen and "Play other tracks while recording new one" enabled in Preferences).

Gale

[steve]

Thanks for the info.