Digital Music FAQ
From MediaMonkey Wiki
What's a Music Database?
One common question is what is a Library or Database and why do I need one. After all, all your music is already on your hard drive, and you can easily play your files by navigating your directories. A database can be considered a searchable list of all of your CD albums and audio tracks. Any album or track that appears in the database is a record of an album or track that physically exists, either in a drawer somewhere (one of your CD albums), on your hard drive (e.g. MP3 files), or on a network. The benefit of having your music stored in a database is that you can quickly search your collection of thousands of files for a single file, and/or organize the files very quickly.
With MediaMonkey, organizing your music, entails:
-Adding your music to a database (MediaMonkey automatically adds your files to the Library)
-Organizing your music by Artist, Album, etc. by simply dragging and dropping Tracks (MediaMonkey updates both the file tags and the database when you perform such operations)
-Automatically moving your files and renaming them into directory structure / filenames that are consistent (this isn't strictly necessary, but helps you navigate your collection when doing so via Windows Explorer)
What's Compressed Audio?
Most media players support several digital audio file formats natively, and others via plug-ins. Some of these formats (e.g. a standard Audio CD) are uncompressed, whereas others (e.g. MP3) are compressed. An uncompressed Audio CD can take up close to 700 MB on your hard drive, whereas the same audio in a compressed format often uses less than 20% of the space. MediaMonkey is able to 'Rip' audio from an Audio CD and save it to your hard drive in a compressed format.
Audio compression can be lossless or lossy. Lossless audio compression compresses the audio without losing any of the original signal's integrity. Consequently, an audio Track that is compressed with lossless compression can be converted back to its original uncompressed form. Lossy compression on the other hand, takes advantage of the fact that the human auditory system doesn't notice certain types of signal degradations, thereby achieving much higher compression ratios. The tradeoff, of course, is that depending on the algorithm used and the compression ratio chosen, lossy compression can introduce artifacts that may be apparent, especially as the compression ratio increases.
The act of compressing an Audio CD and saving it to your hard drive is called 'ripping'. It is done via a CD Ripper which converts the uncompressed tracks on an Audio CD to a compressed format on your hard drive.
What Digital Audio Formats exist? Which is Best?
What follows is a brief description of some of the various formats supported natively by MediaMonkey to help you choose the ideal format for your digital music collection: CDA: CDA (CD Audio) files are the uncompressed files that appear on a purchased Audio CD. They can be played by most players, or ripped to compressed formats to save disk space.
WAV: WAV files are uncompressed and as such, are usually only used for audio Tracks that are not longer than a few seconds. Some users with plenty of hard drive space will convert Audio CDs Tracks to wav files because they are almost universally supported, however, generally, this is not an efficient use of hard drive space.
MP3: MP3 is the most ubiquitous lossy compression format, and MP3 files can be played by most portable digital audio players and many DVD players. MP3s are often ripped at 128 Kbps, achieving decent quality, although the discerning audiophile will often notice artifacts at this bitrate and choose to encode them at a higher bitrate (160 or 192 Kbps).
WMA: WMA (Windows Media Audio) files use a Microsoft format, that, like MP3, is usually lossy (there is a lossless version available, but it is rarely used). It isn't as ubiquitous as MP3, due in part to the fact that it is perceived as a proprietary format and is supported on fewer devices and DVDs than MP3. On the positive side, though, WMA files have noticably better quality than MP3 files encoded at equivalent bitrates.
OGG: OGG is a relatively new format, that like MP3/WMA, is lossy, but is better in quality compared to MP3 files encoded at similar bitrates. What distinguishes OGG from MP3 and WMA is that the format is an open specification and may be distributed freely, meaning that any company can use it at no cost. Few devices support OGG, however, this seems to be gradually changing. For best quality, OGG files are generally encoded at a setting of quality=5 which results in bitrates of ~140-150 Kbps (OGG only uses as much bandwidth as is required).
MPC: MPC is a lossy compressed format that is considered to be one of the best codecs at moderate to high bitrates. At lower bandwidths of 128 Kbps, any benefits over OGG or WMA are less clear. The most significant downside to MPC is that as of today, no hardware devices or portable audio players support the format. MediaMonkey tags and plays MPC files out-of-the-box, but does not yet support encoding.
Monkey's Audio (APE): APE is perhaps the most popular lossless compressed format today. It can store a complete CD in ~1/3 the space of a standard CD without any loss in audio fidelity. MediaMonkey support playback and tagging of APE files but does not yet encode them.
FLAC: FLAC is becoming increasingly popular as a lossless compressed format. It can store a complete CD in ~1/3 the space of a standard CD without any loss in audio fidelity. MediaMonkey supports playback and tagging of FLAC files and encodes them as well.
MediaMonkey can also play other formats via 3rd party plugins. One good example is:
AAC: AAC is a lossy compressed format popularized by Apple's iTunes store. Like OGG and WMA, it is an improvement over MP3, but though it is building in momentum, it is not generally supported by portable audio players other than the iPod.
Ultimately, the decision of what format to use for your audio collection is a personal one, involving tradeoffs between audio quality, hard disk space, portability, and future-proofing. For most, MP3 is more than adequate and its widespread support makes it a no-brainer.
What is DRM?
Some of the formats described above may be encoded with digital rights management (DRM) information. Specifically, WMA tracks that are purchased from online music stores can be encoded with different versions of Microsoft's DRM, while tracks purchased from the iTunes music store are encoded with Apple's Fairplay DRM.
In general, tracks encoded with DRM should be avoided because they can restrict your ability to use them as you see fit--even after you've paid for them. For instance, you may wish to copy the tracks to your MP3 player, however, the DRM might prevent you from doing so. On the other hand, DRM allows some companies to 'rent' music for far less than the cost of purchasing it, and such subscriptions may be worthwhile, depending on your needs.
MediaMonkey supports WMA DRM up to version 9.
For more information see the Electronic Frontier Foundation DRM Page.
What are Tags?
Most digitally encoded file formats also allow Track information to be embedded within the file. For instance, you may have a file 'Bryan Adams - Summer of '69.mp3' in which the filename tells you the Artist and the Title, however, if you wanted to also store information about Album, Track #, Year, Music Genre, Rating, Lyrics, etc. you'd need to store this information in Tags that are embedded within the file.
MediaMonkey allows you to store all sorts of information about a Track within the Library, and to update tags when changes are made to this information. Although the information is stored in the MediaMonkey Library, there are 2 reasons for also updating this information within the track tags as well:
1) If the Track is shared with an external device such as an MP3 Player or DVD, the tag allows that information to be available via the device (assuming the device supports tags).
2) If you wish to use another player or music manager, the tags embedded within your songs can often be read by those applications.
Tags are usually stored in a format that is designed specifically for the file type. e.g. MP3 files usually have ID3 tags wherease OGG files have OGG tags. What follows is a brief discussion of the different tag formats supported in MediaMonkey:
ID3v1: ID3v1 is the lowest common denominator of MP3 tag formats. It stores only a very limited amount of information (e.g. Artist, Title, Album, etc.) however, it is supported almost universally by portable audio players and DVD players.
ID3V2: ID3v2 tags are also used for MP3 files. They support a much greater range of metadata (information about your music files) than ID3v1, however, some information encoded in ID3v2 tags may not be readable by another application or device that also supports ID3v2. For this reason, it's usually a good idea to store music data in both ID3v1 and ID3v2 tags.
OGG, FLAC and WMA files have there own standard tag formats. There's no need for alternatives since the specification supports as much metadata as would be needed in a relatively unambiguos manner.
APE and MPC files use APE2 tags, which are designed to resolve some of the difficulties with ID3v2. Although they work very well, there is limited support for them in portable audio players and DVD players.
What is Volume Leveling?
When tracks are digitally encoded from different sources and using different encoders or encoder settings, they will invariably play back at different volumes on different players and devices. Several technologies have evolved to deal with this problem, and it's useful to understand them so that you use the approach that best meets your needs:
1. Replay Gain
This is the most standardized approach to volume leveling, providing a comprehensive approach for all audio formats without impacting audio fidelity. Replay Gain implementations use a two phase approach: first track volumes are analyzed and the resulting co-efficient is saved to the track's tag. Then, during playback, this tag is read and the player adjusts the volume up or down accordingly. This is an excellent approach for PC-based players, but is limited because many portable devices do not support Replay Gain tags, and thus when tracks are synchronized to a device, the volume will vary.
MediaMonkey supports Replay Gain analysis and playback (via 'Analyze Volume' and 'Level Playback Volume').
This is Apple's variation on Replay Gain. iTunes generates Soundcheck co-efficients which are used to level playback volume. The pros of Soundcheck are that it is recognized by iPod devices and thus volume is leveled even when playing on them without any loss in fidelity. The downside is that it is non-standard, and other Players may not recognize Soundcheck values.
MediaMonkey supports Soundcheck, reading Soundcheck values and converting them to Replay Gain (if no Replay Gain co-efficient exists) as well as converting Replay Gain to Soundcheck on the fly when Synchronizing to an iPod.
3. MP3 Gain
This is a variation on Replay Gain, the difference being that rather than saving the analysis co-efficient to a tag, the volume of the MP3 file is actually modified based on the analysis. The benefits of this approach are that like Replay Gain there is no loss in Audio Fidelity, and the resulting MP3 files can be played at level volumes on any MP3 player. The downside is that the approach is limited to MP3.
MediaMonkey supports MP3 Gain type volume leveling via the 'Level Volume' command.
Whenever tracks are converted from one format to another, the level of the volume can be adjusted. This is useful when there's a need to convert formats, however, for anything else, this is not a desirable means of achieving level volumes since it results in loss of fidelity.
MediaMonkey supports conversion (including CD Ripping and burning) with volume leveling.
5. Audio Normalization
This is an approach used by some Output or DSP plugins that adjust sound levels on the fly during playback to keep them within a defined range. It is generally not recommended as it can introduce audio artifacts.
For more information see the Replay Gain Standard (by David Robinson).