[Ubuntustudio-bugs] [Bug 608964]
Command-line export "(external program)" is also affected. I tested exporting 16-bit silence to Apple Lossless and WMA Lossless. -- You received this bug notification because you are a member of Ubuntu Studio Bugs, which is subscribed to audacity in Ubuntu. Matching subscriptions: Ubuntu Studio Bugs https://bugs.launchpad.net/bugs/608964 Title: Select-all + Export Selected produces different .wav file Status in Audacity: Unknown Status in audacity package in Ubuntu: Triaged Bug description: Binary package hint: audacity Exporting the entirety of a .wav file produces a .wav file with different contents. This is surprising. The "Original" file was actually produced by a previous export from Audacity, so I'm assuming there is nothing special about the format, at least nothing which Audacity does not understand. $ audacity Original.wav Control-A (select all of waveform) File->Export Selection to ExportedFromAudacity.wav File->Exit $ cmp Original.wav ExportedFromAudacity.wav ExportedFromAudacity.wav Original.wav differ: byte 57, line 1 (I will attach demo files) ProblemType: Bug DistroRelease: Ubuntu 10.04 Package: audacity 1.3.12-2 ProcVersionSignature: Ubuntu 2.6.32-23.37-generic 2.6.32.15+drm33.5 Uname: Linux 2.6.32-23-generic x86_64 AlsaCards: 0 [Intel ]: HDA-Intel - HDA Intel HDA Intel at 0xfbaf8000 irq 22 1 [HDMI ]: HDA-Intel - HDA ATI HDMI HDA ATI HDMI at 0xfbbfc000 irq 34 Architecture: amd64 Date: Thu Jul 22 16:44:12 2010 InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100429) ProcEnviron: PATH=(custom, user) LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: audacity To manage notifications about this bug go to: https://bugs.launchpad.net/audacity/+bug/608964/+subscriptions -- Mailing list: https://launchpad.net/~ubuntustudio-bugs Post to : ubuntustudio-bugs@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntustudio-bugs More help : https://help.launchpad.net/ListHelp
[Ubuntustudio-bugs] [Bug 608964]
Also see wiki (link in the URL field), for proposal/discussion of planned/future dither changes. -- You received this bug notification because you are a member of Ubuntu Studio Bugs, which is subscribed to audacity in Ubuntu. Matching subscriptions: Ubuntu Studio Bugs https://bugs.launchpad.net/bugs/608964 Title: Select-all + Export Selected produces different .wav file Status in Audacity: Unknown Status in audacity package in Ubuntu: Triaged Bug description: Binary package hint: audacity Exporting the entirety of a .wav file produces a .wav file with different contents. This is surprising. The "Original" file was actually produced by a previous export from Audacity, so I'm assuming there is nothing special about the format, at least nothing which Audacity does not understand. $ audacity Original.wav Control-A (select all of waveform) File->Export Selection to ExportedFromAudacity.wav File->Exit $ cmp Original.wav ExportedFromAudacity.wav ExportedFromAudacity.wav Original.wav differ: byte 57, line 1 (I will attach demo files) ProblemType: Bug DistroRelease: Ubuntu 10.04 Package: audacity 1.3.12-2 ProcVersionSignature: Ubuntu 2.6.32-23.37-generic 2.6.32.15+drm33.5 Uname: Linux 2.6.32-23-generic x86_64 AlsaCards: 0 [Intel ]: HDA-Intel - HDA Intel HDA Intel at 0xfbaf8000 irq 22 1 [HDMI ]: HDA-Intel - HDA ATI HDMI HDA ATI HDMI at 0xfbbfc000 irq 34 Architecture: amd64 Date: Thu Jul 22 16:44:12 2010 InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100429) ProcEnviron: PATH=(custom, user) LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: audacity To manage notifications about this bug go to: https://bugs.launchpad.net/audacity/+bug/608964/+subscriptions -- Mailing list: https://launchpad.net/~ubuntustudio-bugs Post to : ubuntustudio-bugs@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntustudio-bugs More help : https://help.launchpad.net/ListHelp
[Ubuntustudio-bugs] [Bug 608964]
(In reply to James Crook from comment #14) Discussion moved to QA mailing list: https://sourceforge.net/p/audacity/mailman/message/36288301/ -- You received this bug notification because you are a member of Ubuntu Studio Bugs, which is subscribed to audacity in Ubuntu. Matching subscriptions: Ubuntu Studio Bugs https://bugs.launchpad.net/bugs/608964 Title: Select-all + Export Selected produces different .wav file Status in Audacity: Unknown Status in audacity package in Ubuntu: Triaged Bug description: Binary package hint: audacity Exporting the entirety of a .wav file produces a .wav file with different contents. This is surprising. The "Original" file was actually produced by a previous export from Audacity, so I'm assuming there is nothing special about the format, at least nothing which Audacity does not understand. $ audacity Original.wav Control-A (select all of waveform) File->Export Selection to ExportedFromAudacity.wav File->Exit $ cmp Original.wav ExportedFromAudacity.wav ExportedFromAudacity.wav Original.wav differ: byte 57, line 1 (I will attach demo files) ProblemType: Bug DistroRelease: Ubuntu 10.04 Package: audacity 1.3.12-2 ProcVersionSignature: Ubuntu 2.6.32-23.37-generic 2.6.32.15+drm33.5 Uname: Linux 2.6.32-23-generic x86_64 AlsaCards: 0 [Intel ]: HDA-Intel - HDA Intel HDA Intel at 0xfbaf8000 irq 22 1 [HDMI ]: HDA-Intel - HDA ATI HDMI HDA ATI HDMI at 0xfbbfc000 irq 34 Architecture: amd64 Date: Thu Jul 22 16:44:12 2010 InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100429) ProcEnviron: PATH=(custom, user) LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: audacity To manage notifications about this bug go to: https://bugs.launchpad.net/audacity/+bug/608964/+subscriptions -- Mailing list: https://launchpad.net/~ubuntustudio-bugs Post to : ubuntustudio-bugs@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntustudio-bugs More help : https://help.launchpad.net/ListHelp
[Ubuntustudio-bugs] [Bug 608964]
Focusing on the title and steps to reproduce, I contend that this is correct behaviour. 1. If rectangular dither is used on silence, 0.99 bits of noise are added, and quantization entirely eliminates the dither noise, so the silent audio is exported perfectly. 2. Whilst open, the '16bit' track is held as float values and operated on as float values. There may be an envelope, panning and gain applied, which take the intermediate data outside the values 16 bit can represent. Just as Audacity cannot operate on Mp3 audio without round-trip losses, so too, with its current architecture, Audacity cannot operate on 16 bit without using float as an intermediate. That's an architectural choice, and a good one. Our 16 bit format is held as float whilst in RAM. That is good design. We only pay a 'dither' tax for the extra precision on export or save. An actual 16 bit internal format would be worse, as we would instead pay a 'quantization tax' on every operation on the audio. Since an envelope or gain change IS an operation on the audio as far as the export stage is concerned, we would almost always pay the 'quantization tax' on export rather than as now the (lesser) dither tax. Of course, just as Audacity could have been designed to allow cut and paste and stepped amplification of Mp3 audio without round trip losses, so too Audacity could have been designed to allow cut and paste of 16 bit format without round trip losses. With it's current architecture it comes very close indeed. I'd recommend that when working in 16 bit format users select rectangular dither. That way cut and paste of 16 bit sources including pure silence are unaffected, and at the same time quantization noise on processed or generated audio is handled really well. The shaped dithers may handle the quantization noise very slightly better, but at the cost of disrupting silence. A possible enhancement request is to recommend rectangular dither when 16 bit format is selected as the default in prefs. -- You received this bug notification because you are a member of Ubuntu Studio Bugs, which is subscribed to audacity in Ubuntu. Matching subscriptions: Ubuntu Studio Bugs https://bugs.launchpad.net/bugs/608964 Title: Select-all + Export Selected produces different .wav file Status in Audacity: Unknown Status in audacity package in Ubuntu: Triaged Bug description: Binary package hint: audacity Exporting the entirety of a .wav file produces a .wav file with different contents. This is surprising. The "Original" file was actually produced by a previous export from Audacity, so I'm assuming there is nothing special about the format, at least nothing which Audacity does not understand. $ audacity Original.wav Control-A (select all of waveform) File->Export Selection to ExportedFromAudacity.wav File->Exit $ cmp Original.wav ExportedFromAudacity.wav ExportedFromAudacity.wav Original.wav differ: byte 57, line 1 (I will attach demo files) ProblemType: Bug DistroRelease: Ubuntu 10.04 Package: audacity 1.3.12-2 ProcVersionSignature: Ubuntu 2.6.32-23.37-generic 2.6.32.15+drm33.5 Uname: Linux 2.6.32-23-generic x86_64 AlsaCards: 0 [Intel ]: HDA-Intel - HDA Intel HDA Intel at 0xfbaf8000 irq 22 1 [HDMI ]: HDA-Intel - HDA ATI HDMI HDA ATI HDMI at 0xfbbfc000 irq 34 Architecture: amd64 Date: Thu Jul 22 16:44:12 2010 InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100429) ProcEnviron: PATH=(custom, user) LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: audacity To manage notifications about this bug go to: https://bugs.launchpad.net/audacity/+bug/608964/+subscriptions -- Mailing list: https://launchpad.net/~ubuntustudio-bugs Post to : ubuntustudio-bugs@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntustudio-bugs More help : https://help.launchpad.net/ListHelp
[Ubuntustudio-bugs] [Bug 608964] Re: Select-all + Export Selected produces different .wav file
** Changed in: audacity Status: Confirmed => Unknown -- You received this bug notification because you are a member of Ubuntu Studio Bugs, which is subscribed to audacity in Ubuntu. Matching subscriptions: Ubuntu Studio Bugs https://bugs.launchpad.net/bugs/608964 Title: Select-all + Export Selected produces different .wav file Status in Audacity: Unknown Status in audacity package in Ubuntu: Triaged Bug description: Binary package hint: audacity Exporting the entirety of a .wav file produces a .wav file with different contents. This is surprising. The "Original" file was actually produced by a previous export from Audacity, so I'm assuming there is nothing special about the format, at least nothing which Audacity does not understand. $ audacity Original.wav Control-A (select all of waveform) File->Export Selection to ExportedFromAudacity.wav File->Exit $ cmp Original.wav ExportedFromAudacity.wav ExportedFromAudacity.wav Original.wav differ: byte 57, line 1 (I will attach demo files) ProblemType: Bug DistroRelease: Ubuntu 10.04 Package: audacity 1.3.12-2 ProcVersionSignature: Ubuntu 2.6.32-23.37-generic 2.6.32.15+drm33.5 Uname: Linux 2.6.32-23-generic x86_64 AlsaCards: 0 [Intel ]: HDA-Intel - HDA Intel HDA Intel at 0xfbaf8000 irq 22 1 [HDMI ]: HDA-Intel - HDA ATI HDMI HDA ATI HDMI at 0xfbbfc000 irq 34 Architecture: amd64 Date: Thu Jul 22 16:44:12 2010 InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100429) ProcEnviron: PATH=(custom, user) LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: audacity To manage notifications about this bug go to: https://bugs.launchpad.net/audacity/+bug/608964/+subscriptions -- Mailing list: https://launchpad.net/~ubuntustudio-bugs Post to : ubuntustudio-bugs@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntustudio-bugs More help : https://help.launchpad.net/ListHelp