Thread: [Audacity-devel] Export multiple discarding track start information
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From: Markus M. <me...@me...> - 2009-02-28 09:44:42
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Hi, when I use "export multiple", using tracks as separation criterion, the empty space, i.e. silence at the beginning of the tracks is not exported. That is, when one uses "export multiple", then later imports the tracks again, those are not aligned anymore. Is this the expected behaviour? Markus |
From: Richard A. <ri...@au...> - 2009-02-28 16:42:55
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On Sat, 2009-02-28 at 10:44 +0100, Markus Meyer wrote: > when I use "export multiple", using tracks as separation criterion, the > empty space, i.e. silence at the beginning of the tracks is not > exported. That is, when one uses "export multiple", then later imports > the tracks again, those are not aligned anymore. > > Is this the expected behaviour? It is, and certainly it has been the behaviour for as long as I've been doing things to Export Multiple. What gets exported is all the audio data in the track. Given that the long blank space before the track is not composed of silent samples but space with no data in it, it doesn't get exported. This is correct for the purposes for which Export Multiple is mostly used, i.e. breaking up a long recording into multiple short tracks, because you split the long track into many short tracks, which get exported (minus their leading silence) as the items in the recording. I can see however that for other purposes (e.g. translating an Audacity project into another package) there is a need to keep the tracks exported aligned with each other. I think what this really needs is a header in each of the exported files that says where it is supposed to go (in some defined time units) and can be read by a loading application to put the files in the right places. This isn't a new idea, it's pretty much what AES31 support does using BWF for the exported files and defining a timecode header in the BWF chunk in order to locate each file on the timeline when the audio is imported. I'm not sure what the adoption has been like, but it seems a good route to pursue if that is what you are trying to achieve. Richard |
From: Markus M. <me...@me...> - 2009-02-28 17:00:19
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Richard, thanks for the suggestions. I also found that it the space will be converted to null samples if you do "mix and render" on each track at least once. You are correct that the best thing would be to add metadata to the track files, but that doesn't help when files must be imported into other applications which do not care about whether Audacity writes that metadata or not. Maybe I'll have a look at what it would take to add an option to the export multiple dialog to export the silence also. Markus Richard Ash schrieb: > On Sat, 2009-02-28 at 10:44 +0100, Markus Meyer wrote: >> when I use "export multiple", using tracks as separation criterion, the >> empty space, i.e. silence at the beginning of the tracks is not >> exported. That is, when one uses "export multiple", then later imports >> the tracks again, those are not aligned anymore. >> >> Is this the expected behaviour? > > It is, and certainly it has been the behaviour for as long as I've been > doing things to Export Multiple. What gets exported is all the audio > data in the track. Given that the long blank space before the track is > not composed of silent samples but space with no data in it, it doesn't > get exported. > > This is correct for the purposes for which Export Multiple is mostly > used, i.e. breaking up a long recording into multiple short tracks, > because you split the long track into many short tracks, which get > exported (minus their leading silence) as the items in the recording. > > I can see however that for other purposes (e.g. translating an Audacity > project into another package) there is a need to keep the tracks > exported aligned with each other. I think what this really needs is a > header in each of the exported files that says where it is supposed to > go (in some defined time units) and can be read by a loading application > to put the files in the right places. > > This isn't a new idea, it's pretty much what AES31 support does using > BWF for the exported files and defining a timecode header in the BWF > chunk in order to locate each file on the timeline when the audio is > imported. I'm not sure what the adoption has been like, but it seems a > good route to pursue if that is what you are trying to achieve. > > Richard > > > ------------------------------------------------------------------------------ > Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA > -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise > -Strategies to boost innovation and cut costs with open source participation > -Receive a $600 discount off the registration fee with the source code: SFAD > http://p.sf.net/sfu/XcvMzF8H > _______________________________________________ > audacity-devel mailing list > aud...@li... > https://lists.sourceforge.net/lists/listinfo/audacity-devel |
From: Vaughan J. <va...@au...> - 2009-02-28 23:04:51
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Btw, "Save Compressed Copy of Project" writes each track as an OGG and the project file saves offset for each track. So, that's a way to currently do an effective Export Multiple and at least have the offset data retrievable, fwiw. - Vaughan Markus Meyer wrote: > Richard, > > thanks for the suggestions. I also found that it the space will be > converted to null samples if you do "mix and render" on each track at > least once. > > You are correct that the best thing would be to add metadata to the > track files, but that doesn't help when files must be imported into > other applications which do not care about whether Audacity writes that > metadata or not. > > Maybe I'll have a look at what it would take to add an option to the > export multiple dialog to export the silence also. > > > Markus > > Richard Ash schrieb: > >> On Sat, 2009-02-28 at 10:44 +0100, Markus Meyer wrote: >> >>> when I use "export multiple", using tracks as separation criterion, the >>> empty space, i.e. silence at the beginning of the tracks is not >>> exported. That is, when one uses "export multiple", then later imports >>> the tracks again, those are not aligned anymore. >>> >>> Is this the expected behaviour? >>> >> It is, and certainly it has been the behaviour for as long as I've been >> doing things to Export Multiple. What gets exported is all the audio >> data in the track. Given that the long blank space before the track is >> not composed of silent samples but space with no data in it, it doesn't >> get exported. >> >> This is correct for the purposes for which Export Multiple is mostly >> used, i.e. breaking up a long recording into multiple short tracks, >> because you split the long track into many short tracks, which get >> exported (minus their leading silence) as the items in the recording. >> >> I can see however that for other purposes (e.g. translating an Audacity >> project into another package) there is a need to keep the tracks >> exported aligned with each other. I think what this really needs is a >> header in each of the exported files that says where it is supposed to >> go (in some defined time units) and can be read by a loading application >> to put the files in the right places. >> >> This isn't a new idea, it's pretty much what AES31 support does using >> BWF for the exported files and defining a timecode header in the BWF >> chunk in order to locate each file on the timeline when the audio is >> imported. I'm not sure what the adoption has been like, but it seems a >> good route to pursue if that is what you are trying to achieve. >> >> Richard >> >> >> ------------------------------------------------------------------------------ >> Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA >> -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise >> -Strategies to boost innovation and cut costs with open source participation >> -Receive a $600 discount off the registration fee with the source code: SFAD >> http://p.sf.net/sfu/XcvMzF8H >> _______________________________________________ >> audacity-devel mailing list >> aud...@li... >> https://lists.sourceforge.net/lists/listinfo/audacity-devel >> > > ------------------------------------------------------------------------------ > Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA > -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise > -Strategies to boost innovation and cut costs with open source participation > -Receive a $600 discount off the registration fee with the source code: SFAD > http://p.sf.net/sfu/XcvMzF8H > _______________________________________________ > audacity-devel mailing list > aud...@li... > https://lists.sourceforge.net/lists/listinfo/audacity-devel > > |