Monday, May 22, 2006

Auto-Exposure Bracketing: An Idea Whose Time has Come

On this last trip to Yosemite, I finally tried out auto-exposure bracketing (AEB) on the Canon 20D. I had used this feature on earlier point-and-shoot digital cameras, but on an SLR it seemed a bit heretical. Aren't you supposed to fiddle with exposure and metering to get everything exactly right in one shot? Can't you slap on graduated neutral density filters and polarizing filters to keep sky detail from being blown out?

Well, it turns out there's nothing inherently wrong with using AEB on a good camera. I used it extensively to shoot landscapes, rushing rapids, waterfalls, and people in front of all of the above -- situations with a lot of dynamic range, or rapidly changing light, or unpredictable metering such as when you hand the camera to someone else to shoot a picture of you.

Along the way, I learned a lot about the 20D's advanced options for bracketing, and how to sort, choose, and combine the results in Photoshop. I'll turn these lessons into a series of articles on my new (yet-to-be-named) digital photography blog.

Sunday, May 21, 2006

Prius: Tire Pressure and Gas Mileage

On our first trip to Yosemite National Park in the Prius, the average miles per gallon worked out to 48.0. But lately, commuting and puttering around town has been getting 46 and change. The only change car-wise is the addition of a bike hitch, which adds maybe 30-40 pounds total. That doesn't seem like enough to account for the difference.

I read that underinflated tires can lower MPG by about 2% for each pound of lost pressure. The Prius recommended pressure isn't written on the wheels, and it isn't listed on the door jamb or in the owner's manual. It's actually on a sticker on the inside of the glove compartment. Turns out the front and rear tires should be 35 and 33 PSI respectively, and they were about 2 pounds low according to the tire gauge.

Normally, a figure like "2% better gas mileage" is hard to get my head around. But with the Prius getting close to 50 MPG, that 2% is around 1 mile per gallon. Sure enough, inflating the tires an extra 2 pounds resulted in an extra 2 MPG for this trip, clocking in at exactly 50.0. (On arrival at Yosemite, we were actually up to 52.)

Thursday, May 11, 2006

Birth of an iTuNation

To keep long music-related posts from overwhelming this personal blog, I've set up a new one strictly for posts related to iTunes, iPod, and music in general:


Sunday, May 07, 2006

iTunes: iPod-Only Playlists

Anyone can enhance their iPod experience by making some iTunes playlists that are used exclusively on the iPod. In particular, iPod-only playlists are useful for:
  • Trimming big playlists to fit onto a small iPod.
  • Trimming huge playlists so that you have enough space for other things on a big iPod.
  • Minimizing synching time for playlists that only need to hold enough for a specific trip (say, your daily commute).
  • Simplifying the synching process for a multi-iPod household.
  • Quick lookup for a particular song or artist, without navigating through several distracting layers of menus.
The Outline

I have a 4 gigabyte iPod Nano, which isn't nearly enough to hold all my songs. When I listen on the go, I want to have a wide selection, broken down into two main categories: favorite music, where the songs have high ratings and potentially appear in several different playlists, and unfamiliar music where the songs are unrated and/or have low play count.

I also have a 40 gigabyte iPod (pre-video), which often skirts the edge of being able to hold all the music I want to bring with me. It's easy to download several gigabytes at a time of South-By-Southwest indie rock, Grateful Dead concerts, then get an unpleasant surprise when a synch doesn't have enough room for all the songs, or when I try to use the iPod for file storage and discover there's almost no room left.

When listening in iTunes, I want the widest selection possible, so I have one Smart Playlist with all my 3-5 star songs, another with all my 4-5 star songs, another with all my unrated songs, another with
all the unrated songs with zero play count, and so on. (In addition to my standard playlists where I've picked out each song myself.)

The core technique for iPod-only playlists is to make Smart Playlist "clones" of some of these other playlists, varying the conditions a little so that they work better on the iPod than the original playlists.

With this technique, it's essential to choose the setting "Synch selected playlists" in Preferences > iPod. Each iPod has its own separate setting, so you'll pick different sets of playlists depending on which iPod is plugged in. If more than one is plugged in at the same time, choose the iPod name from the dropdown inside the Preferences > iPod dialog.

Space Savers

The key consideration with an iPod is, thou shalt not run out of space. You might think this is easy to guarantee if you have a big iPod with many gigabytes free, but things can change in a heartbeat:
  • You can download a big song collection. These days, you're likely to find hundred of free songs all packaged together in a promotional download from the South-By-Southwest conference, or dozens of free full-length concerts from the Internet Archive.
  • You can get a second, smaller iPod and find that your current system of playlists doesn't work for a 2-iPod setup.
  • You can decide to use your big iPod for backing up critical files, and realize that you have to free up several gigabytes.
Thus, to save space with an iPod-only playlist:
  1. Identify each playlist that has the potential to grow beyond what your iPod can comfortably hold (given that you might use the iPod to hold lots of other playlists and/or data files).
  2. Identify each playlist used for unfamiliar music that holds more songs that you could listen to between synch sessions. For example, if you rate unfamiliar songs during your daily commute, and sych that iPod once a week, do a back-of-the-envelope calculation to figure out how much total time the playlist needs.
  3. Make a folder in iTunes by selecting the Library icon in the Source list and choosing File > New Folder. Give the folder the same name as the iPod.
  4. Inside this folder (i.e. select the folder before creating each playlist), create a new Smart Playlist for each of the original playlists you're cloning. Name the new playlists by concatenating the original playlist name and the iPod name, for example "My Top Rated - Joe's iPod".
  5. Give each Smart Playlist a single condition, "Playlist is Name of Original Playlist". This creates a clone of that playlist.
  6. Check the box that limits the size of the new playlist. Choose a measurement that makes sense in this context. For example, when dividing up space on my 4 GB Nano, I give each playlist a fixed number of megabytes so I can allocate or free specific amounts of space when the iPod is almost full. On a bigger iPod, I choose perhaps 100 songs selected by rating to get the "top 100", or a specified number of hours to last through a week-long trip away from the computer.
  7. If the original playlist is a mix of good, bad, familiar, and unfamiliar songs, you can add an extra condition like "My rating is between **** and *****" or "Play count is greater than 0", so the iPod-specific playlist contains only your most familiar or favorite songs. For example, I might have a "Flamenco" playlist in iTunes, while its iPod-only clone only contains my favorite Flamenco songs.
  8. Plug in the iPod, set it to synch only selected playlists, and choose the ones from the appropriate folder. Because the iPod preferences show playlists in a single big list, you'll need to give them distinctive names as above so that you can tell them apart from the original playlists.
Repeat the process for each iPod you have.

Time Savers

Do you ever get a craving for a particular song, artist, or album while listening to your iPod? If you're right in the middle of a playlist, satisfying that craving can be very disruptive -- keep pressing the menu button until you get to the main menu, then navigate down by song, artist, or album scroll through some very long lists, and maybe in the end you didn't really want every song from that artist or album, so you must navigate more menu levels and scroll through more lists. To top it all off, now you're out of the original playlist, even if you just wanted to listen to one song.

The trick here is to take advantage of a few subtle properties of iPod playlists:
  • Once a song is on the iPod, there's really no penalty in including the same song in multiple playlists. So why not make variations of the same playlist?
  • The iPod has a single global setting for Shuffle Play, unlike iTunes which lets you choose shuffle or sequential play for each playlist.
  • Whatever order you sort a playlist in iTunes, the songs are listed in the same order when you bring up that playlist on the iPod.
Can you see where this is going? Using the same technique as in the last section, you can make Smart Playlists that are clones of other playlists:
  1. Just use one condition, "Playlist is Name of Other Playlist".
  2. Don't set any limit on the size.
  3. Use a name that reflects the original playlist but adds some qualifying information. For example, I have playlists "My Top Rated (song)" and "My Top Rated (artist)". (I would have made the names a little longer, except that anything longer is truncated in the iPod listing.)
  4. Sort the playlist by the appropriate column. Then never touch that playlist again! Use the original playlist for searching or fiddling with song info.
  5. In iPod preferences, check that playlist so that it's automatically synched with the iPod, in addition to the original playlist.
Now, instead of listening to "My Top Rated" on the iPod, I listen to its clone, like "My Top Rated (song)". If I get a sudden craving for a particular song, I press the menu button once to get to the list of songs in this playlist, then scroll straight to that song because the names are listed in alphabetical order. If I want to zero in on a particular artist, I press the menu button twice to get to the list of playlists, move to the adjacent playlist to switch to the same list of songs arranged by artist, and scroll through the songs alphabetized by artist. As a bonus, I see in this playlist only the favorite songs from that artist, not all the others that might happen to be on the iPod.

The same technique applies any time you want to access the same list using different criteria. For example, you might have a playlist full of podcasts sorted by Date Added, so you could listen to episodes in order. But you might have another playlist with those same podcasts sorted in order of time, so that you could pick a long or short one to match the length of a drive.

Advanced Tip: Pseudo-Shuffle Playlists

I mentioned earlier how the iPod has only a single, global Shuffle setting. Again, this can lead to inconvenience if you're listening to songs in random order and want to quickly switch to sequential play, or vice versa. You have to navigate to the main menu, down into Settings, change the Shuffle setting, then come back up and go to Now Playing or navigate to some other playlist.

For example, in the case where you start jonesing for a certain band, you probably want to hear several songs in a row from that band. Even if you switch to a playlist arranged by Artist, that doesn't help if Shuffle Play is still turned on -- you can pick the next song, but iPod will jump randomly when it finishes.

There are enough instances when it's helpful to turn off Shuffle Play -- sequence of podcast episodes, that I sometimes leave it off for long stretches. As a shortcut, instead of turning Shuffle back on, I'll use even another playlist, like "My Top Rated (random)", where the songs are already in shuffled order.

Let's think about that a minute. Even if you don't go the extra step to create this final playlist, how would you get the songs in unpredictable order? You could sort by some other column like Time or Size, but then the songs at the start would be kind of weird (either very long or very short). Most other columns are largely blank; for example, sorting by Comment gives you the songs with Comment fields in order by that field, then all the ones with blank Comment fields in order by song name. No good there.

iTunes has a little-understood notion called "Play order", represented by the column of numbers on the left, with no column title. Click on the unnamed column title, and you'll see the essential order that iTunes thinks the songs should be in for that playlist. (Either ascending or descending, depending on the direction of the arrow in the column header.) With the playlist sorted by that column, click the Shuffle icon in the bottom-left (looks like two snakes having a good time), or option-click the icon if Shuffle is already turned on for that playlist. You'll get a whole new randomized order for that playlist, that you can utilize on the iPod to give you random play even if Shuffle Play is turned off.

Periodically, I'll get sick of always seeing the same first screen of songs every time I go into a particular iPod playlist. Reshuffling them in iTunes and synching again helps keep them fresh, and I could swear that even Shuffle Play turns up more interesting songs after a playlist is re-randomized like this!

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Thursday, May 04, 2006

iTunes: Music Backups for Music Collectors

In this article, I address a topic that's bugged me for years: how to back up your big and/or fast-changing music collection through iTunes.

Serious nerds don't feel the need to do anything special to back up their music, because they're already backing up their whole computer all the time. But that's cumbersome if you have a big music collection, or if your music library is spread across multiple drives, or if you frequently make changes to song info. (Any such change updates the MP3 file so the backup software backs it up again. Any change to the artist, album, or song title can cause the file to get renamed, messing up the way the backup software tries to track changes to the same file.)

The man on the street can burn a CD or DVD from iTunes every now and then. has a popular page showing how to do that. But that's cumbersome if you have a big music collection, or you keep a lot of songs unchecked but still want to back them up.

There must be a middle ground, a technique using iTunes but still flexible enough to handle extensive music libraries!

The Outline

As in the OneDigitalLife article, the core of this technique is a smart playlist that accumulates all your recently added songs. That is, it has a "Date Added" condition so that all music added since the last backup appears in the playlist automatically. At periodic intervals, or after the playlist grows big enough to make a backup worthwhile, you burn it to one or more CDs or DVDs. Then you reset the "Date Added" condition so the playlist becomes empty, and gradually fills up again as new music is added.

The Essential Smart Playlist

Let's call this Smart Playlist "Backup - Monthly", for lack of a better name. Later, we'll rename it temporarily while doing the actual backups.

We're actually going to go a bit farther than a single-condition playlist; we'll add some touches to make the process work better.

Use a between test for the "Data Added" condition. Make the second date be way off in the future. For example, right now my "Backup - Monthly" Smart Playlist has the condition "Date Added is in the range 4/30/06 to 12/31/06". For most backups, you'll leave the end date alone, but if something goes wrong with a multi-disc backup and it stretches over more than one day, you can set the end date to the date you started the backup process. If you import more songs or fix some typos in song info partway through the backup process, you want to save those songs for the next go-round.

Use a second condition, also with between and the same start and end dates, for "Date Modified". Changes to song info, such as the song name, track number, comments, year, and so on are all stored inside the song file. After you fill in blank fields or correct mistakes and typos, those song files need to be included in the next backup. ("Date Modified" is not changed when you add a rating.)

Before burning the playlist, change its title to something that makes a sensible CD title, since iTunes titles the CD the same as the playlist name. For example, most of the time my Smart Playlist is titled "Backup - Monthly", but before the most recent backup I temporarily changed its name to "Backup - April 2006", then back again after burning the discs.

Don't set a size limit on the playlist. If it's too big for a single data disc, iTunes automatically splits it across multiple discs. Under Preferences > Advanced > Burning, leave the Disc Format set to Data CD or DVD, which ensures that all the files in the playlist are burned to disc. (MP3 CDs omit AAC, MOV, PDF, or other filetypes that you can manage in iTunes.)

Leave the checkbox unchecked for "Match only checked songs". Even though iTunes leaves unchecked songs out when it burns discs, you want them in this playlist. You'll see why in a minute.

Do check the box for "Live updating", so that the playlist grows whenever you add or change a song. You can play games with this checkbox if something goes wrong during the backup and you need to restart it or remove things from the song list. But as a standard practice, leave it checked.

Leave the playlist sorted by either (Song) Name or Artist (or, rarely, Album). The sort column determines how the files are arranged on the burned discs. Sort by song name, and the files are all placed at the top level of the CD, with no directory structure. Sort by artist name, and the songs for each artist go into a directory named for the artist. Sort by album name, and the songs from each album go into a directory named for the album. In each case, an ascending sequence number is tacked on to each item in the root of the CD.

I prefer to sort by artist, because the artist names are easy to scan, and if I'm going to import the songs somewhere else I'll probably do that for all the songs by that artist. I don't sort by song name because I want the song files on disc to keep their original names without the leading 001 etc. If the files are renamed, it's harder to locate or compare against the original files, and I've had the sequence numbers show up in the song titles when I imported the renamed files on another computer. I don't sort by album name because it's hard to tell one "Greatest Hits" album from another without a lot of work fixing up album titles.

Leave the playlist sorted the way you want when you first create it, and doublecheck the sort order before each time you do a new backup.

The Supplemental Playlists

Here's where one of my pet peeves with iTunes comes in: there's not a whole lot you can do with unchecked songs.

I uncheck songs for lots of different reasons -- because I have the same song on both a regular and "Greatest Hits" album, because I've ripped the same CD or downloaded the same Grateful Dead concert at different bit rates, or to keep audio book and other long files out of certain playlists. (Yes, you can also set the "Skip when shuffling" setting for a song, and add extra conditions to Smart Playlists based on Length and Kind, but the checkbox is a convenient shortcut that works in all situations.)

However, I do frequently want to burn discs and include all the unchecked songs. Maybe I'm making a backup copy of a CD ripped at multiple quality settings; maybe I'm about to get rid of a bunch of 2-star songs, but want a backup of those songs in case I change my mind someday.

iTunes makes this process kind of roundabout. Skip to the next section if you don't care about unchecked songs. Otherwise, please bear with me!

What we'll do is use a standard playlist to hold a list of the unchecked songs. We'll turn on the checkboxes for all songs in this playlist, burn the disc(s), then uncheck them again.

Make a new Smart Playlist titled "Backup - Monthly - Checked". Give it one condition, "Playlist is Backup - Monthly" (or whatever name you gave to the Smart Playlist you're using to do backups). Don't check the Limit box, check the "Match only checked songs" and "Live updating" boxes. Now we have a playlist containing only the checked songs from our backup list. We'll use this playlist for no other purpose than to figure out what songs in the backup list are unchecked.

Make a new Smart Playlist titled "Backup - Monthly - Unchecked". Give this playlist two conditions, "Playlist is Backup - Monthly" and "Playlist is not Backup - Monthly - Checked" (or whatever names you used for the previous two playlists. Now you've got a list of all the songs whose checkboxes you must flip while making the backup.

Now make yet another playlist, a standard one this time, titled "Backup - Uncheck afterwards". When you're ready to do a backup, drag and drop the Smart Playlist "Backup - Monthly - Unchecked" onto it, so that it lists the same songs as that Smart Playlist. Select all the songs in this playlist, right-click over one of them, and choose "Check Selection" from the pop-up menu. The songs disappear from the "Backup - Monthly - Unchecked" playlist, but remain here so you can uncheck them later. Most importantly, they will now be included in your backup.

All these playlists, just for backups, can clutter up your Source list in iTunes. Here's where folders come in handy. Make a new folder by selecting the Library icon in the Source list and choosing File > New Folder. Call it, oh I dunno, Backups. Drag and drop each of the backup-related playlists in there. Now you can get at them all at once, and hide them in between backups.

Feel the Burn

OK, at this point, you're ready to actually do a backup. To include your whole library, edit the conditions in the "Backup - Monthly" Smart Playlist so that the start date is in the distant past, before you started with iTunes. Otherwise, take a look in your "Recently Added" Smart Playlist to see when you added your last big batch of songs.
  • You've got the "Backup - Monthly" playlist sorted by the correct column to give the desired CD layout, right?
  • You've renamed that playlist temporarily to include the date or some detail to help you remember why you're backing up this particular batch of songs, right?
  • If any of the songs in the playlist are unchecked, you've set up the supplemental playlists as described above, then checked all the necessary songs, right?
  • Your disc format in Preferences > Advanced > Burning is set to Data CD or DVD, right?
  • You've looked at the total size of the playlist (at the bottom of the iTunes window, when the playlist is selected) to see whether you need a CD, a DVD, or multiple discs, right?
OK, select the playlist to burn, click the Burn icon in the upper-right corner of the iTunes window, and click Burn again after inserting a CD or DVD.

If your backup fits on a single disc, skip ahead to the "Aftermath" section. Otherwise, keep reading to learn the finer points of multi-disc backups.

Multi-Disc Backups

If the playlist is too big to fit onto a single disc, iTunes prompts you when the first disc is finished, then automatically continues burning a second, third, etc. disc until the whole playlist is done.

As each disc is burned, the status area at the bottom of the iTunes window shows how much is left to go. If you've already burned one or more DVDs, but the remaining songs would fit on a CD, you can pop in a CD and iTunes will happily use it for those last few songs.

As each disc is burned, iTunes also shows (with icons and grayed-out song names) which songs go on the current disc. Make a note of the first and last songs, on this disc, so that if something goes wrong you'll know where to pick up.

What could go wrong? During multi-disc backups, I've had (a) iTunes crash after finishing each disc, (b) iTunes error out while burning, creating a useless "coaster", (c) no power failure yet but I'm sure that's coming.

If your backup gets interrupted like this:
  • Edit the conditions for your backup Smart Playlist to turn off live updating.
  • Delete from the playlist all the songs successfully burned to disc.
  • Start burning again with a new disc.
  • Afterwards, turn live updating back on for the Smart Playlist.
Sometimes, these crashes occur while I've left a disc burning overnight, and maybe the next day I can't afford to tie it up burning more discs, or maybe I'm out of discs and need to make a trip to the office supply store. So the process stretches out over 2-3 days or even more. In cases like this, edit the two between conditions in the Smart Playlist so that the end date is the day you started the backup. That way, any songs added in the interim won't sneak in or be skipped over by mistake. You're deliberately leaving them until the next backup.

The Aftermath

Once you've completed a backup, potentially with multiple disks and temporarily checked songs, just a little cleanup makes things simpler for next time:
  • Set the beginning date of your "Date Added" and "Date Modified" conditions to the day you did (or started) the backup.
  • If you turned off live updating due to a failure partway through the process, turn it back on now.
  • If you temporarily checked some songs, go back to the "Backup - Uncheck afterward" playlist, select all the songs, right-click, and choose "Uncheck selection" from the pop-up menu. Then remove all the songs from that playlist.
  • It's not a bad idea to select the backup playlist, choose File > Export Song List and store a copy of the backup playlist somewhere for posterity. You can consult the list someday if you're looking for a song and the backup discs aren't easily accessible.
  • Rename the backup Smart Playlist to a generic name like "Backup - Monthly".
Happy iTuning!

Frequently Asked Questions

Seriously, why not just use dedicated backup software?

I don't have a whole lot of room left on my hard drive(s) even for music, so backing up to another drive isn't practical, I need to burn discs.

If I need to recover a song, it's easier for me to get it from a clearly labelled disc with a folder structure arranged by artist, rather than browse through some months-old representation of my entire directory structure within a backup program.

When I pop in a disc burned by iTunes, I can browse it within iTunes, drag-and-drop songs straight into the library, and recover their original ratings. Recovering a song via backup software means recovering the file back to its original location, then finding that location and importing back into iTunes.

I'm not expecting to recover my entire library this way, more likely audio books or podcasts that I trashed due to lack of space, low-rated songs that I changed my mind about, and so on.

Backup software isn't smart when files move around or change names. With iTunes, I might split a music library across drives, consolidate all songs on a new bigger drive, or change the file path by editing the song name, artist, or album. iTunes knows which of these operations requires backing up the song again better than Retrospect or what have you.

Related Reading

OneDigitalLife article about iTunes backups

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