Help for Audacity on GNU/Linux.
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This forum is for Audacity on GNU/Linux.
Please state:
- which version of Linux you are using,
- the exact three-section version number of Audacity from Help menu > About Audacity,
- whether you installed your distribution's release, PPA version, or compiled Audacity from source code.
Audacity 1.2.x and 1.3.x are obsolete and no longer supported. If you still have those versions, please upgrade (see
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Gale Andrews
- Quality Assurance
- Posts: 41761
- Joined: Fri Jul 27, 2007 12:02 am
- Operating System: Windows 10
Post
by Gale Andrews » Fri Sep 26, 2014 8:52 pm
Interesting they consider there that libvo-aacenc is the worst quality of all the AAC encoders and the native FFmpeg AAC encoder almost the best. A few years ago the native encoder was regarded as the worst (which I can confirm from tests at the time).
The Zeranoe builds of FFmpeg for Windows use libvo-aacenc, but I have not tested recently against other encoders for sound quality.
If anyone reading this wants to encode low sample rate AAC in Audacity, perhaps for ringtones or speech, note that rates below 22050 Hz will produce a zero bytes file with the native FFmpeg encoder or libfaac, but libvo-aacenc does not have that problem. It's an Audacity bug.
Gale
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Gale Andrews
- Quality Assurance
- Posts: 41761
- Joined: Fri Jul 27, 2007 12:02 am
- Operating System: Windows 10
Post
by Gale Andrews » Sat Sep 27, 2014 4:34 am
steve wrote:Unfortunately, using Audacity's built in export options provide no control over the quality settings for AAC export (the quality slider in "Options" does nothing). The version of FFmpeg in Debian Wheezy is rather old and not officially supported by Audacity 2.0.6
I think the "unsupported FFmpeg version" must be the problem. In Ubuntu 14.04, the Audacity AAC quality slider does work with FFmpeg 2.2.3 configured with the native FFmpeg AAC encoder. It works on Mac too with the native encoder in FFmpeg 2.2.2.
I suppose your FFmpeg might be using libfaac. I'll test libfaac if there is any fix for the slider not working with libvo-aacenc. Perhaps the latter only being CBR is something to do with it?
Gale
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steve
- Site Admin
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- Operating System: Linux *buntu
Post
by steve » Sat Sep 27, 2014 4:45 am
Gale Andrews wrote:Interesting they consider there that libvo-aacenc is the worst quality of all the AAC encoders and the native FFmpeg AAC encoder almost the best.
According to:
https://trac.ffmpeg.org/wiki/Encode/AAC ... estquality
"Which encoder should I use? What provides the best quality?
For AAC-LC the likely answer is: libfdk_aac > libfaac > Native FFmpeg AAC encoder (aac) > libvo_aacenc"
Gale Andrews wrote:I suppose your FFmpeg might be using libfaac.
It's using libvo_aacenc (and it does not seem as bad at the above quote might suggest. I've not done any careful comparisons (I don't normally use AAC), but it doesn't sound bad, and I don't see any nasty quirks (which I did notice with the Nero encoder).
