Double or Triple Your Ipod’s Capacity With High Efficiency AAC

I got my first ipod two months ago and in fact it was my first mp3 player ever. Shocking for hard core geek right? Well I bought my wife her own ipod a number of years ago but was never able to really afford a second one so I became victim of ‘what cd do i want to bring with me today?’. Over time many of my cds became scratched and dirty from piling up in the center console of my car and I longed for my own portable music device that I could carry around my entire music collection without worry. When the device of my destiny arrived in the mail from my parents for my birthday you can imagine my excitement to immediately cram as much crap on it as I could. I was having a blast until…. I ran out of space. I had only gotten maybe a third of what I really wanted on there but it was all that 8 gigabytes could stand. To put this into perspective I have a 500Gb usb hard drive which houses my archived collection so you can imagine cherry picking that down to 8Gb is an excercise in futility.

There is a solution for the hopelessly indecisive like me.

Compatibility:

Please note this tutorial will only work for you if you have an ipod released after the Fall of 2009. This is because only the latest ipod firmware supports HE-AAC. I used a 5th generation ipod nano for this article. Older ipods supposedly will play the files at less fidelity since they don’t take advantage of the SBR codec extensions.

Here is what you will need:

1. You must have itunes installed (Don’t worry, we’re not actually going to use it, we only need it for the ipod driver it provides).

2. Grab the Foobar2000 media player. At the time of this article, 1.0 has just been released and that is the minimum version you will want. This is the most awesome power-user media player that exists.

Install these programs and then proceed.

3. Grab Ahead Software’s free standalone AAC encoder. This is by far one of the best AAC encoders out there.

Unzip this somewhere that you can find again (Example: “C:\codecs“).

4. Grab the foo_dop foobar component. This is the plugin that adds ipod support to foobar2000, it’s much more powerful than itunes.

Extract foo_dop.dll into your foobar2000 components folder. This is typically located at “C:\Program Files\foobar2000\components” although this may vary depending on your environment.

Now for the most difficult step, configuring foobar2000. Given this program is targeted towards audio power users it’s not much to look at and it’s option-heavy so I will try to make this as simple as possible without requiring you to know the ins and outs of foobar2000. Please note, I am making the assumption your ipod has already been initialized and configured.

Configure Media Library

The first thing you need to configure in foobar2000 is the media library. Foobar2000 creates a database locally to keep track of all of your songs, their meta data, and any other useful information. To configure you media library, go to “File->Preferences” and select ‘Media Library’ in the option tree in the left pane. Next Click ‘Add…’ to point to a folder that contains your media files that foobar will scan. As a side note: Don’t panic if you use a different media player to manage your music already, you can continue use your existing software since foobar2000 will not modify your file structure at all. Once you have added your folders to your music library, it will seem as though foobar2000 is not doing anything but I assure you it is getting busy scanning your files. To prove it, you can click on “View->Console” and you can monitor the progress. This can take several minutes depending on the size of your collection; it is advisable to wait for it to finish.

A Quick Note About ReplayGain

ReplayGain is program/setting/standard that adjusts the gain levels on your tracks so the volume level is consistent. We’ve all experienced that jarring effect of going from one track to the next only to have to dramatically adjust the volume because it its too loud, or we just can’t hear it well enough  because the volume is set for the loudness of the previous track. Fortunately for us, foobar2000 has a ReplayGain integrated natively therefore we can have it apply the proper replaygain levels and use them when playing the files back.

I don’t want to go into too much detail about ReplayGain since that’s a topic all in it’s own however I would recommend applying replaygain to all over your files. This can be done by selecting the files in your playlist view, right-clicking on them and selecting one of the options in the ReplayGain context menu. You will see that there are 3 options for scanning the files (Scan Per-File Track Gain,  Scan Selection as a Single Album, and Scan Selection as Albums (by tags)). Per File means it will use a global gain level that transcends across all albums. Single Album will adjust the track gain to the average gain level of the album it belongs to. By tags, will do both, so I recommend using that.

Configure iPod Manager

Now you can configure how foobar2000 interacts with your ipod by going back to “File->Preferences”. In the option tree on the left, if you have correctly installed foo_dop, you should see iPod Manager. Select it and you will be presented with several tabs.

Database

If your meta tags on your files are standard, than you should not need to change any metadata mappings on this tab. The only thing I recommend setting here, is the SoundCheck Source. SoundCheck is Apple’s moniker for ReplayGain, and works exactly the same. The drop down has either Track Gain or Album Gain as options; choose accordingly. I prefer Track Gain since I like to shuffle my playlist.

Conversion

This is the important tab; it controls how your files are transcoded before being transferred to your ipod, this is the killer feature that itunes lacks that brought you here. Make sure you check ‘Convert audio tracks in unsupported formats’, and ‘Convert audio tracks with a bitrate above’. The bitrate in the following checkbox is the threshold at which the file being transferred will be re-encoded at a lower bitrate. This is a critical part of the process since it will compress our large bloated files into more efficient files so we can fit more. The threshold you set is up to you, but I have mine set to 96 kbps which pretty much guarantees that everything will get transcoded unless its already in our target format/bitrate.

For the encoder, you will need to browse to the location where you extracted the Nero AAC encoder file. Point it to ‘neroAacEnc.exe’.

For the parameters use the following: ‘-q 0.3  -ignorelength -if – -of %d’

The -q setting is where the magic happens, by using 0.3 or a lower value, the encoder will automatically use the AAC/SBR (Also known as HE-AAC) mode for the encoder which is what allows us to cram so much sound quality into so few bits. Any value above this, will leave the codec in AAC/LC mode which won’t sound so good at a low bitrate. I use 0.3 as my q setting but I’ve been told you can go lower (as low as 0.25) and still get acceptable quality.

Use m4a for your extension so it your files are automatically recognized as aac/mp4.

If you have a multi-core processor in your computer you can get away with more concurrent encodings, this will transcode more than one file at a time. If you can get away with it, do it, otherwise leave it be.

Last, make sure ‘ReplayGain scan converted files’ is selected so the file’s SoundCheck levels get recorded onto your ipod.

Click OK and you should be ready to proceed.

Add Songs to Your iPod

The easiest thing to do at this point is create a playlist that you want to transfer to your ipod. Start by going to “Library->Album List”. You will see a window popup with all of your albums in your library. Scroll through you library and right click on the ones you want and select ‘Add to Current Playlist’. Once your playlist is constructed, select everything in it and right click, then click “iPod->Send to iPod”. This will start the process of transcoding your playlist into AAC/SBR and transferring it to your ipod. Depending on the size of your playlist, this process could take some time so get a cup of coffee or go watch a movie.

When the transfer has been completed, you should have all of your files available on your ipod. To verify, click on “View->iPod Devices” and click on your ipod in the list. You should see a new playlist tab appear in the background. This tab is showing you the contents of your ipod. The default playlist layout for foobar2000 may not be terribly informative so you may want to add some columns to your view. You can do this by clicking on the grey header bar above your list. It will probably already have track title, track no, playing, etc, so from the context menu that pops up, select columns, and then check all of the columns you want to be visible in your playlist view. I usually add Codec and Bitrate so I verify that my files transcoded properly. If you went with my recommendations, you should see ‘AAC/SBR’ in the Codec column, and the bitrates for each song should average around 80-90kbps.

When you are finished, don’t forget to eject your ipod by clicking on “File->iPod->Eject” and wait for it to tell you it’s ok to disconnect your ipod. If you don’t follow this process, your ipod database may become corrupt.

Now listen to your music and tell me that it doesn’t sound amazing for how low the bitrate is. You’ll be amazed how many songs you can fit onto your ipod with these settings.

Now if you are a hard core take no prisoners audio-phile, than you will probably never be happy with any form of lossless compression and no doubt you may notice some loss of dynamic range. The target audience for this article are those who are seeking ‘near transparency’, meaning it sounds ‘good enough’. I am pretty picky about my audio quality and I can testify that I am blown away by how well HE-AAC works and would definitely swear by it.

Enjoy.

Footnotes:

HE-AAC Details