Hi, I'm using Audacity 2.1.0 in a Windows 8.1 x64 PC, and I've found a bug.
I've imported into Audacity a FLAC audio track, which length is 4m 10s 435ms. I've exported it to mp3 (transcoding) using latest LAME version 3.99.3. The output mp3 file's length is 4m 10s 485ms.
So Audacity is adding 50ms more of silence, from the start/beginning of the song. I've noticed it cause I've zoomed in the 2 tracks (previously imported into Audacity) to compare both and hear to the possible quality loss, and I've seen that the tracks were not matching. I've used 2 output settings: best variable bitrate with standard speed and 320kbps constant bitrate. Both settings have the same result, an mp3 50ms longer.
Not big deal, but I think it's an important bug to fix, since audio sync is really important.
Thanks!
Track length varies when exporting audio
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This forum is for Audacity on Windows.Please state which version of Windows you are using,
and the exact three-section version number of Audacity from "Help menu > About Audacity".
Audacity 1.2.x and 1.3.x are obsolete and no longer supported. If you still have those versions, please upgrade at https://www.audacityteam.org/download/.
The old forums for those versions are now closed, but you can still read the archives of the 1.2.x and 1.3.x forums.
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rambomhtri
- Posts: 230
- Joined: Thu Jan 02, 2014 11:05 am
- Operating System: Windows 8 or 8.1
Re: Track length varies when exporting audio
That's a normal characteristic of MP3 encoding. As I'm sure you know, MP3 is lossy compression so there are changes...
If it's a problem, use a different format. As far as I know, AAC and OGG don't have this issue. Or, use a lossless format.
If it's a problem, use a different format. As far as I know, AAC and OGG don't have this issue. Or, use a lossless format.
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rambomhtri
- Posts: 230
- Joined: Thu Jan 02, 2014 11:05 am
- Operating System: Windows 8 or 8.1
Re: Track length varies when exporting audio
Yeah, MP3 is lossy, it compresses data and the sound quality worsens. But in any way the length of the track should be changed. It's logical.DVDdoug wrote:That's a normal characteristic of MP3 encoding. As I'm sure you know, MP3 is lossy compression so there are changes...
If it's a problem, use a different format. As far as I know, AAC and OGG don't have this issue. Or, use a lossless format.
I'd like to use MP3 cause I'm working with songs.
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Gale Andrews
- Quality Assurance
- Posts: 41761
- Joined: Fri Jul 27, 2007 12:02 am
- Operating System: Windows 10
Re: Track length varies when exporting audio
AAC does add silence padding, OGG doesn't.DVDdoug wrote:That's a normal characteristic of MP3 encoding. As I'm sure you know, MP3 is lossy compression so there are changes...
If it's a problem, use a different format. As far as I know, AAC and OGG don't have this issue. Or, use a lossless format.
Please see http://lame.sourceforge.net/tech-FAQ.txt.rambomhtri wrote:Yeah, MP3 is lossy, it compresses data and the sound quality worsens. But in any way the length of the track should be changed. It's logical.
Gale
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rambomhtri
- Posts: 230
- Joined: Thu Jan 02, 2014 11:05 am
- Operating System: Windows 8 or 8.1
Re: Track length varies when exporting audio
Wow, I didn't know that. I don't understand very well why you need to add silences, but it seems to be that it's necessary in order to playback correctly and MP3?Gale Andrews wrote:AAC does add silence padding, OGG doesn't.DVDdoug wrote:That's a normal characteristic of MP3 encoding. As I'm sure you know, MP3 is lossy compression so there are changes...
If it's a problem, use a different format. As far as I know, AAC and OGG don't have this issue. Or, use a lossless format.
Please see http://lame.sourceforge.net/tech-FAQ.txt.rambomhtri wrote:Yeah, MP3 is lossy, it compresses data and the sound quality worsens. But in any way the length of the track should be changed. It's logical.
Gale
Thank you very much for the info.