[General Topics] Menneisyys:
1.2 AAC and enhanced versions

With the latest format, AAC, which seems to be all the rage now, the situation is vastly different. First, if you really want to save some storage, you MUST use the most space-conserving HE-AAC v2, which allows for file sizes of about half or third (!) of those of WMA’s or MP3’s - of the same quality(!). No wonder a lot of Internet radio stations are quickly switching to HE-AAC v2 streams – after all, FM-quality, stereo, 44 kHz streams can be broadcast at 24…32 kbps, which is just unbelievable with any other audio compression technology, including even the latest WMA and RealMedia technologies.

This is the most enhanced and, on Windows Mobile (the two other mobile OS’es are far better supported in this respect) still pretty scarcely supported format. This can clearly be seen in the chart. For example, not even the built-in PWMP or the current version of CorePlayer support it (only the significantly “dumber” versions of AAC: HE-AAC and LC-AAC, which don’t help much with saving storage). Unfortunately, currently, all the Windows Mobile players cause around 55% CPU usage (at 208 MHz), which corresponds to significantly decreased battery life.

With not so advanced (and, therefore, not very commonly used – except for iTunes, which uses these as the default format, and not the much more advanced HE-AAC v2) AAC versions, there’re significant differences. In there, PocketMusic 5.01 turned out to be the worst choice (followed by the GSPlayer / MortPlayer duo and, then, Nero Mobile Pro and TCPMP) and (as one would expect) CorePlayer the best, followed by the built-in WMP in Windows Mobile phones (but, again, NOT in non-phone-enabled Pocket PC’s – that is, Windows Mobile Classic devices. The WMP in these does’t support AAC at all).

1.2.1 Symbian / Nokia

In this respect, the built-in Music Player in the Nokia N95 is far-far better. The following power usage shot shows the HE / HE2 / LC / MP3 / WMA playback power usage in Music Player. As can clearly be seen, HE-AAC v2 (again, the second in the chart) only consumes about 0.02-0.03W more than the “dumber” HE / LC versions. (Also see THIS for more info on how this graph should be interpreted.)

(Another quick Symbian-related note: Unfortunately, the (currently, for audio playback under Symbian) not THAT recommended CorePlayer behaves much worse in this respect: it starts burning much more power at the first third(?) of every song, regardless of the format, as can be seen in the following two screenshots:

(HE / HE2 / LC / MP3 / OGG playback)

Another example: playing back WMA files in order:

(the first section of the chart shows the built-in Music Player playing back exactly the same songs. As can clearly be seen, it didn’t exhibit the same huge power usage peaks as CorePlayer.)

This, however, means playing back podcasts or loooooong files in CorePlayer won’t result similar problems; the following screenshot shows the case of playing back a 2.5-hour-long MP3 podcast:

As can be seen, the high power usage didn’t “kick in” in the first hour. I don’t, however, know what would have happened after that, when it would have kicked it in and for how much time.

I don’t know what this bug is caused by; hope the CoreCodec folks fix this.)

1.2.2 (Pocket) Windows Media Player (on phone devices) and AAC

Still speaking of the (HE-)AAC support of the built-in Windows Media Player in Windows Mobile, it, unfortunately, is unable to stream as SHOUTcast / Icecast AAC(+) streams can be seen in THIS screenshot. That is, while it supports the playback of local AAC files, it can’t stream them. The situation is the same with Conduits’, otherwise, highly recommended Pocket Player. This all is an unfortunate result of the AAC decoder that HTC has licensed - it's not as componentized as developers would have liked. It takes over the complete audio path when called (its output can't even be redirected to A2DP, for some reason). Neither can HTC’s Streaming Media stream AAC, unfortunately. That is, for the time being, you MUST stick to third-party apps to stream AAC (as is also explained HERE) – and, of course, to play back local HE-AAC v2 files. Unfortunately, the same is true on Symbian, where Music Player has absolutely no streaming capabilities and, therefore, you must rely on third-party apps like CorePlayer or Nokia’s brand new Internet Radio. The latter two, however, still doesn’t support HE-AAC v2 and will only play them back in mono and greatly reduced quality.