I imported a 320 bit MP3 song into Audacity… made some changes and now I want to export it.
2 Questions -
when I hit export, what is the best option to use in order to ensure that I maintain maximum audio quality?
EX… I can’t see choosing to export as an MP3 file as the file was already compressed in the 1st place (320 MP3 bit rate as mentioned.) So that would not seem to make sense.
Do I just use .wav as that is the most lossless?
2 ) Depending on what answer you give me to my question (above), when I add the song to I-tunes… what do I do then to maintain best quality? As you know you can pull the file into I-tunes as an MP3, or a wav file, etc.
Bottom line is … I made changes to a song using Audacity and now want to get it back in I-Tunes without losing ANY quality!
So since the file was compressed in the 1st place. If I export as a .wav won’t the wav file be smaller than most though since the file was already compressed to begin with? OR, does Audacity change the file to a .wav while you are working on it and if you export it as a .wav file it will be just as large as any other 3 min song that you add to I-Tunes as a .wav file?
(Get what I am assuming here?.. or is that NOT how it works) Ha
Sadly, the only editing that is possible (by any program) of MP3s without decoding them first is very basic editing (such as trimming the length, changing the volume, splitting into multiple files, and not much more). This limitation comes from the way that MP3 is encoded.
There are editor programs which do not force the compression cycle and we recommend those if you want really simple MP3 editing. The instant you want production filtering or effects, you’re dead.
There is a producer who makes a radio show somewhere in the northeast US by downloading music, putting together a show and then posting it to a broadcast radio station. They were more or less OK until the station decided to put a compressed version of the show on their web page as a podcast. The music quality went straight into the toilet and his question was how to prevent that.
Take at least one or hopefully more than one MP3 compression step out of the pathway.
That’s not just strongly recommended, that’s the only way to prevent that kind of damage.
When we left him, I think he had sweet-talked the broadcast station into letting him post the show as a very high quality Audio CD instead of MP3 delivery.
If you are doing “simple” editing, such as cutting/splicing or volume changes, try [u]MP3DirectCut[/u]. It doesn’t de-compress/re-compress, and since it’s working directly on smaller-compressed files it’s very fast.
Most “effects” can’t be done without decompressing, and you can’t do mixing or crossfading without first decompressing.
does Audacity change the file to a .wav while you are working on it and if you export it as a .wav file it will be just as large as any other 3 min song that you add to I-Tunes as a .wav file?
The size of a WAV file is simply related to the playing time, the bit depth (the number of bits per sample), the sample rate (the number of samples per second) and the number of channels. (mono or stereo, etc.). If you know that information, and if you know there are 8-bits in a byte, you can calculate file size.
For example, a “CD quality” WAV file is 16-bit stereo, so that’s 4 bytes per sample. And, it has a sample rate of 44.1kHz so there are 44,100 samples per second, for a total of 176,400 bytes per second. Multiply that by 60 and you get about 10MB per minute Or for a CD (or equivalent WAV) you can calculate a bitrate of 1411kbps (kilo_bits_ per second).
iTunes supports ALAC, which is lossless compression similar to FLAC. I believe iTunes can convert a WAV file to ALAC. An ALAC or FLAC is about 60% the size of the uncompressed WAV.
The different qualities are not called out like that. You just have to know.
Audacity default WAV export is 44100, 16-bit Stereo or Mono depending on the show. Audio CD is 44100, 16-bit, Stereo too, but there are no options. Broadcast is 48000, 16-bit, Stereo. They use very slightly higher sample rate because they have a lot of elbow room. They had the advantage of sitting next to a video signal the size of Albania, so designing a higher quality sound signal was trivial by comparison.
One of the ways they made Audio CD as efficient as possible was to publish the specifications and reduce the options to zero. That’s what lets you tell people they can get 80 minutes on an Audio CD. Full Stop. There are no options. It’s actually less than that. I use the 78 minute number to be safe.
There is no ‘Mono instead of Stereo’ CD and get twice as much stuff on there. Audio CD burning software makes a Stereo show whether you want it or not.
The CD designers were competing with top quality analog vinyl which could be (and still is) really good. People went to their graves claiming they could hear significant difference between the two, but for the vast majority of music listeners, the only difference was music with no cat-hair pops.