Bug? Win7 64bit with Play & Pause of 2 tracks

[GiacomoGo]

Easily reproduced for me on Win 7 64-bit.
Bottom line: Unable to play a few seconds of each separate track, Pause each separate track, and *keep* each separate paused location.
Audacity gets confused, and is unable to keep track of separate "paused" locations. Seems unintended to me.

Open 2 separate tracks in Audacity (right-click in Win Explorer -> Open with -> Audacity).
This gives me 2 separate Audacity windows.
Ctrl+Shift+F on each window to fit the track to each window.
Play (Space) one track, the Pause (P). (Or use the buttons.)
Alt+Tab to switch to the 2nd Audacity window.
Play (Space) 2nd track, then Pause (P).
... Bug? Audacity has lost track of the Pause (P) location of one or both tracks. I can no longer Alt+Tab between windows & continue playing each from their paused locations.

[kozikowski]

You have never been able to open two independent instances of Audacity. The best you can do is two different views of the same show. I think Effects UNDO is linked as well. If you went back and forth applying effects to first one window and then the other, they will UNDO that way as well, regardless of which window has focus.

Koz

[steve]

You have never been able to open two independent instances of Audacity.

To add a bit of detail:
If you open Audacity and then open another project in Audacity, you actually only have one instance of Audacity running, but have two "project windows" open. There are several (mostly technical) reasons why you can't run more than one instance of Audacity. One important reason, which relates to this question, is that Audacity does not directly play or edit audio files. Audio data is copied into a temporary data location as multiple (often thousands) of short "blocks" of audio. This enables Audacity to quickly access and modify any part of the show without needing to read or write the entire file. On the other hand, it means that Audacity requires complex book-keeping to keep track of all of the audio data fragments. If two or more instances of Audacity were running at the same time, there would be a high risk of "data collision" (where one instance of Audacity attempts to read or write data belonging to another instance of Audacity). Audacity is able to handle multiple projects simultaneously because it is running as one instance, thus the program is aware of the data structure for every project that is open, and so is able to avoid data collisions.

Ramifications of this are that only one project may be in play or record mode at a time. "Pause" is a temporary suspension of Play or Record, but Audacity is still in "play mode" or "record mode" while paused. If you play or record in one Audacity project and then switch to another project and press play, in order to play that second project Audacity needs to stop playback in the first so that it can then switch to give the second project access to the mixing engine. If Audacity did not do that, then data from the two projects would get mixed up in an erratic and dangerous way.

More information about how Audacity handles data in this article in the manual: http://manual.audacityteam.org/o/man/au ... jects.html

[steve]

I think Effects UNDO is linked as well

No, Audacity keeps separate Undo stacks for each project that is open. Audacity ensures that each project has a separate data folder, even when sharing the same temp directory, so that projects can retain their integrity, and undo histories while multiple projects are open. Although this mechanism appears to be fairly robust these days, I still prefer to work in one project at a time. Care needs to taken when working on multiple projects simultaneously to ensure that you do not modify data belonging to one project in another project. It is quite easy (through user error) to inadvertently mess up both projects by overwriting a file used in one project from another project, so I am not a fan of that way of working.

[Gale Andrews]

If you use File > Import > Audio... or drag the files in from Explorer you can have them in the same project.

If you prefer to have the files in separate project windows then use SHIFT + A to Stop and Set Cursor instead of Pause. Then when you switch project windows you can use SPACE to restart from the last stop position in either project.


Gale

[kozikowski]

Undo stacks for each project that is open.

Maybe yours does. I swear I needed to apply different filters and remove them on two different windows and they followed the order of application, not the window focus. That's when I gave up to make a cuppa.

Koz

[steve]

I swear I needed to apply different filters and remove them on two different windows and they followed the order of application, not the window focus.

If you can reproduce that, it would be worth starting a new topic.
I can't reproduce that here.