Q My large (1,500-strong) CD collection consists of classical music and jazz. If I were to rip the collection as a backup to an external drive and/or place the files in the cloud, I would want to retain the quality with Aiff/Wav or compression to Apple Lossless (m4a) with the idea of being able to convert back to the uncompressed original in due course. Do you think this is practicable? Also, would Apple Lossless be the best format to choose to temporarily compress Aiff or Wav files for storage, in order to uncompress them for playback later? Also, to stream music to hi-fi etc, are these files the best formats to use, or are they problematical? Michael, via email

A When ripping your CD library, it's important to choose the best storage format to preserve your music collection's original quality. To the audiophile market and to a lesser extent for some music lovers, digital music has a pretty bad name. This is due to historically low bit-rates in lossy consumer music formats like MP3 or AAC (a lossy compression format is one that permanently removes some of the file's data; in some cases it will remove more data than it leaves behind). Today, higher bit-rate MP3 and AACs are much better than they were.

Thankfully, iTunes supports some lossless (compressed and uncompressed) formats, including Aiff, Wav and Apple Lossless. But lossless formats often take up much more space on disk (up to about 11Mb/min), and are not supported by most online music lockers, including Google Music.

When ripping CDs to your iTunes library you can choose higher bit-rate MP3 and AAC (192kbps or 320kbps), an uncompressed audio format such as Aiff or a lossless compression format like Apple Lossless. These all have the same quality as a CD. iTunes is also pretty good at detecting your music and automatically populating your library with metadata where supported.

Below is an overview of the various lossless formats:

Apple Lossless Compression



This Apple file format option in iTunes can reduce the stored data by almost 50%. It restores to a bit-perfect replica of the original music file for playback. The Apple Lossless Audio Codec (Alac) was open-sourced in 2011, so there is relatively good support, with iTunes on OS X and Windows, Music on iOS, and third-party audio players such as PowerAmp on Android offering support.

It's worth noting that iOS only supports up to 44.1kHz audio, so if you intend to transfer any of these to your phone, be careful to not use 96kHz settings. ALC fully supports metadata tagging, which is great for searching your collection.

WAV (Waveform Audio File Format)



WAV is capable of storing Linear PCM audio (the digital encoding format used on CDs) in uncompressed form. Ripping a CD and storing it as an uncompressed WAV results in a bit-perfect clone – identical to the original CD. WAV files can also store high-resolution music files at greater bit and sampling rates than CDs. Some places offer them as "hi-def" or "studio masters". Uncompressed WAV files can be ripped and played back in iTunes and are very high quality. However, they do take up more hard drive storage space than AAC, MP3 or Apple Lossless. WAV files do not support metadata tagging. Things like album art, song titles and other features that enhance music library management and playback will be lost.

AIFF (Audio Interchange File Format)



AIFF is similar to WAV and is capable of storing uncompressed Linear PCM audio. AIFF files can also store high-resolution music files at high bit depths and sampling rates. AIFF files can be created and played back in iTunes on Mac OSX and Windows and are very high quality. But they are still very large uncompressed files. AIFF files, like Apple Lossless, fully support metadata tagging.

Storing digital music files in lossless or uncompressed form does not mean that you have to reduce the amount of music stored on your iOS devices or other players. iTunes allows users to convert higher data rate music files to 128kbps AAC on the fly as music is synchronised to a mobile device. There is no need to keep separate libraries. Many devices are, though, capable of playing lossless files.

When it comes to backing up your uncompressed files, for now at least, you will need to keep them stored on a physical drive or an online backup service such as Backblaze or Crashplan. This is because no online music lockers that I know of currently support them without compression.

As for streaming music to a hi-fi system, Apple Lossless is likely to be the best format as files can be transported in compressed form and decoded on the hi-fi, which should result in faster playback.

Q I'm going travelling soon and would like to set up a blog to share stories and photographs of my travels with my family and friends. I'm only going to have a phone and tablet with me, so something with apps and draft support would be really useful, Gerald, via email

A There are a multitude of blogging systems and services that can be used by people travelling the world, and a few of them meet your criteria perfectly, including Wordpress, Tumblr and Roon.io.

Depending on your level of technical expertise, Wordpress is the most flexible option. It offers free, open-source software that can be run on any server you wish and tuned to your liking. There are lots of guides on the web for doing this, although you will have to pay for servers and a domain name.

For people who do not wish to set up a server, there are two options with native applications: Tumblr, which offers first party apps on iOS, Android and Windows Phone, and Roon, which offers first party applications for the iPhone and iPad.

Tumblr is a very popular service with a community of people generating and sharing content. The website offers a plethora of custom themes for your blog, supports custom domain names and more.

You can take a look at http://tumblr.com – however, Tumblr does not offer a way to export your data, so that if you ever wish to back it up or move the material elsewhere, there is no easy way of doing so.

Roon is a relatively simple but powerful blogging service that puts the focus on your content and offers incredibly good iOS apps (when the service launched, they were the only way to create and edit content).

Roon has developed a business model, offering custom domains and analytics to generate revenue and keep the service alive.

It also offers a way to download all of your content and images in a single go – you retain the ownership of your data. You can find the service at http://roon.io.