diff --git a/wiki/audio.md b/wiki/audio.md index 047a6b6..96887f1 100644 --- a/wiki/audio.md +++ b/wiki/audio.md @@ -9,7 +9,7 @@ Music and Audiobooks can be obtained by buying the digital files or by Podcasts need a so called Podcatcher. A Podcatcher is used to subscribe to podcasts and download them automatically. -## Media software +## Media Software If you want to keep your system clean of much data, you can use this kind of setup. @@ -33,16 +33,58 @@ There are differences depending on your preffered software interface. It is self-hostable and can be dockerized. It has a web-interface and does not feature client software. -## Audio codecs +## Audio Formats -An audio codec is an encoding of an audio file. -There are lossy and lossless codecs, the latter not compromising quality for +An audio format is an encoding of an audio file. +There are lossy and lossless formats, the latter not compromising quality for smaller file sizes. -Following is a list of codecs written about in this wiki: - -- [flac](./flac_(codec).md) is a lossless codec - -## Extract audio files from CDs +Following is a list of specific and often used formats: + +- wav is an uncompressed lossless format +- aiff is an uncompressed lossless format +- [flac](./flac_(codec).md) is a compressed lossless format +- alac is a compressed lossless format +- ape is a compressed lossless format +- mp3 is a compressed lossy codec +- aac is a compressed lossy codec +- wma is a compressed lossy codec +- ac3 is a compressed lossy codec usually found in DVDs +- dts is a compressed lossy codec usually found in DVDs + +### Lossy and Lossless Formats and Their Conversion + +Music files can either be encoded lossy or lossless. +Lossless formats can be converted from and to each other without loosing +information. +Lossless formats can also be converted to lossy formats to make the files +smaller and save space. +Files should not be converted to lossy formats more than once. +Additionally lossy formats should not be converted to lossless formats as it +increases the file size without adding any audio information. +These not recommended conversions are called bad conversions. + +#### Detect Bad Conversions + +The bitrate, format and the sample rate can be usually checked with simple +tools. +For Linux a simple software solution for this is the `file` command. +Running it will display these features of a given audio file. +This will however only display the format features. +Bad convserions as described in +[the previous section](#lossy-and-lossless-formats-and-their-conversion) can not +be detected by this. +A spectral analysis can detect bad conversions. +For this a audio analyzer like +[Sonic Visualizer](https://www.sonicvisualiser.org/) is needed. +Select a audio file and press `Add Spectogram` under `Layer`. +This will display a spectogram. +Music off of a retail CD and lossless songs have frequencies that extend at +least up to 22kHz. +If the frequency extends up to these 22kHz the file is lossless for sure. +If the frequency is cut before and the file is encoded in a lossless file it is +has undergone a bad conversion and is not really lossless. + +## Extract Audio Files from CDs You can convert your CDs to files on your computer. This way you don't have to search for your CDs all the time. @@ -55,20 +97,20 @@ This way you don't have to search for your CDs all the time. - [MusicBrainz Picard](./picard.md) for linux is a graphical user interface for tagging files of many different formats. -## Quality analysis of different versions of an album +## Analysis of Different Versions of an Album While deciding on what version of an album is the best visit [Dynamic Range DB](https://dr.loudness-war.info). It shows dynamic range scorings of each version. -## Get additional data to an album/single +## Get Additional Data to an Album/Single If additional information for an album is needed, visit [Discogs](https://www.discogs.com). Discogs has tracklists, dates and more information to nearly all versions of albums and singles. -## Naming convention +## Naming Convention It is suggested to place the audio files in a directory named after the album they belong to.