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endless loop - gaps

Posted: Tue Apr 11, 2017 9:32 am
by cisz
I have Audacity 2.1.0 and am using Windows 7 pro x64.

I want to create an endless loop of whitenoise. It seems to do it successfully in Audacity when I test it with "shift+space" but when I export it to the windows wav 16 bit pcm, it plays back (in windows media player) with a gap between the loops.

Also, I wasn't able to find a zero crossing point (t doesn't look like there is one).

I've attached a copy of the file.

Help appreciated.

Re: endless loop - gaps

Posted: Tue Apr 11, 2017 10:48 am
by steve
cisz wrote:I've attached a copy of the file.
Loops perfectly for me in Audacity.
cisz wrote:Also, I wasn't able to find a zero crossing point (t doesn't look like there is one).
Not relevant for white noise. It's "random" noise, so the loop point can be anywhere so long as the track is long enough to not have significant periodicity.
cisz wrote:t plays back (in windows media player) with a gap between the loops.
The problem is with the player.
For gapless playback, the player needs to cue up the "next track" (which for a loop, is the start of the loop file) so that it is ready to go immediately.
I don't use Windows Media Player, but you could try enabling "Crossfading" (I expect that details for how to do so are available via Google).
Alternatively you could try a different audio player (for example: http://www.foobar2000.org/)

Re: endless loop - gaps

Posted: Sun Dec 03, 2017 11:44 am
by cisz
When I test the loop using shift+ space in Audacity it loops ok but if I try playing the exported wav file using "play" (in Audacity) it ends at the end of the loop.

I want to create an endless loop that will play constantly on an audio/video dvd player (not a computer player).

Thanks.

Re: endless loop - gaps

Posted: Sun Dec 03, 2017 7:55 pm
by DVDdoug
I want to create an endless loop that will play constantly on an audio/video dvd player (not a computer player).
CD/DVD players have a physical limitation... When it gets to the end of the disk the laser has to physically move back to find the beginning. (Hard drives have a similar physical limitation, but they are buffered... They read-ahead.)

Regular audio CDs are limited to about 80 minutes, so you can go 80 minutes without a gap. But if your player can play MP3s, you can put 5-10 times as much on a CD disc, and about 5 times that on a single-layer DVD.* So... Theoretically you should be able to get more than 40 hours on a DVD. But Audacity might choke on a 40-hour program (Audacity uses 32-bit floating point "Internally" so it would take a huge amount of storage before you export to a more-compressed format.)
It plays back (in windows media player) with a gap between the loops.
I couldn't get WMP to work either, but I did get it to work in Winamp. just made a 30-second "noise" MP3 and in turned-on Repeat and Crossfade in Winamp. I couldn't hear a gap when it looped/repeated.






* Most DVD players can play MP3, but not all. If you have DVD authoring software you can make an "audio only" DVD with Dolby AC3 audio at about the same compression/bitrate as MP3, and that disc will play on any DVD player.

Re: endless loop - gaps

Posted: Mon Dec 04, 2017 10:59 am
by cisz
The dvd player says it's an mp3 decoder.

Could you explain how to increase the record time using mp3?

Thanks.

Re: endless loop - gaps

Posted: Tue Dec 05, 2017 10:00 am
by cisz
Or maybe I should ask - would you be able to recommend a free burning software that is able to make an "audio only" DVD with Dolby AC3 audio?

I assume that type of software is able to compress the file so that it plays longer?

Re: endless loop - gaps

Posted: Mon Jan 08, 2018 12:39 pm
by cisz
What I'm thinking is to create an 8 hour audacity file using "repeat". Then compress it in mp3 format (using audacity) to fit on a cd and hopefully it will play for 8 hours using this cd/dvd player that is able to play mp3s?

Re: endless loop - gaps

Posted: Tue Jan 09, 2018 1:27 am
by kozikowski
Is the real job you want to produce the DVD Splash Screen so it lasts a long time (Play Movie, Languages, Subtitles, etc). Because of the laser resetting above you can't actually do that without a hit. However, we discovered the solution is to produce the first four or five loops as one video. It looks as if it's looping gracefully, but it's not. Nobody ever stays around for the minute or so it takes to run out of that first video. And even if they do, they'll be too busy checking their Friend Status and Tweet History to notice.

And then it resets (with the hit) and you get another minute.

Koz

Re: endless loop - gaps

Posted: Tue Jan 09, 2018 1:30 am
by kozikowski
You can make a DATA DVD that will hold 8 hours of MP3 show. I don't know the magic of actually playing it, but I think most machines with optical drives should be able to do that. It looks like a shiny, thin hard drive.

Koz

Re: endless loop - gaps

Posted: Tue Jan 09, 2018 12:15 pm
by cisz
I'm trying to make an audio only file of white noise that I can use to drown out other noise while in bed. I've got a 7 second clip of white noise that I extended to 8 hours using "repeat". Now I want to compress it to fit on a cd.

DVDdoug wrote:
Regular audio CDs are limited to about 80 minutes, so you can go 80 minutes without a gap. But if your player can play MP3s, you can put 5-10 times as much on a CD disc, and about 5 times that on a single-layer DVD.* So... Theoretically you should be able to get more than 40 hours on a DVD. But Audacity might choke on a 40-hour program (Audacity uses 32-bit floating point "Internally" so it would take a huge amount of storage before you export to a more-compressed format.)