AACplus/HE-AAC playback on Ipod 5G Video

[Gamesoul Master]

I currently own a Nano 2G, but I really need a larger iPod. So I'm thinking that since Rockbox will probably never support the 2G Nano's (I was considering getting an 8 GB Nano because I really like the Nano's), I've been leaning towards getting a 30 GB Video. Mainly for the higher storage and to have Rockbox.

However, because of how much music I listen to, I tend to prefer HE-AAC encoding of my music for higher quality with smaller file sizes. After reading the FAQ, going through the Wiki, and searching the forums... I really couldn't find any definite answer to whether Rockbox supports it or not. I found references to it not quite running in realtime, so I assume there must be *some* kind of support, otherwise people wouldn't be able to really talk about how fast the decoder works (can't very well talk about the speeds with any certainty about something that doesn't exist, right?).

So basically, I'm wondering if there is support for HE-AAC. I don't care about what encoder needs to be used or anything (I can figure that part out myself), I just need to know if the support is there. And, well I suppose it'd be nice to know if, under any conditions, an ~80 kbps HE-AAC song could be decoded at least in realtime. Thank you for your time, and I apologize for the long post here... I just wanted to explain my reasoning and such before anybody decided to possibly ask about it...

[Llorean]

It's unlikely to be decoded realtime on the iPods. If you must use HE-AAC use a Gigabeat. But you may want to try other formats available in a listening test. You might be surprised at how low a bitrate you can achieve with some other ones at an acceptable quality.

[Gamesoul Master]

Well, I've noted that I can take HE-AAC down to about ~60 kbps (VBR of course) with high quality encoding. And while I find it hard to believe that any other format besides mp3pro could even come close to that, I'm not about to rule anything out. Especially considering that I'm currently using LC-AAC on my iPod, using VBR set at 30 (about 95-135 kbps).

The concept with the quality is that I listen to all my music at max volume... and indication of lower quality usually doesn't sit well with me. But you give a good (and simple) idea... a listening test is probably the best course of action. I assume that this is the list I should be looking at for what is supported?

And just to ask (based on looking at the details given on that list)... it does seem to say that HE-AAC is implemented (even if it doesn't decode in realtime so well). With the understanding that I probably won't get far with it... is it actually there (just for me to experiment with a bit)? The only reason I have such interest in HE-AAC is because not only have I gotten used to mp4 quite a while ago, but my phone also plays back HE-AAC music, and I'm long used to encoding, tagging, etc, in mp4 formats. But if I do end up finding a better format for Rockbox on the iPod to use, I'll have no regrets...

[saratoga]

As Llorean said, AAC-HE is implemented, but you will need a Gigabeat to play it in real time due to the extremely high CPU demands of the format.

[Gamesoul Master]

Ahh... I wasn't sure if he meant it was there but not realtime, or *if* it were implemented it wouldn't be realtime. Thank you both for taking the time to answer my questions.

While I've never had good (or bad) things to say about Toshiba, I'll have to look into these Gigabeat players... I suppose since I'd have Rockbox running on it, the only things I'll really have to look up are things like max volume output, battery life, price, etc. Well, either way... I'll definitely take a look at those too. Thanks again.

[Llorean]

In all seriousness, you shouldn't be using the maximum volume output of these players. It is damaging to your ears, and you should consider getting some more isolating earphones so you can listen at lower levels.

[Gamesoul Master]

Makes sense. I actually bought a pair of Sennheiser earbud headphones that output 112 dB (the highest I could find for earbud headphones), just because all the headphones I tried elsewhere couldn't handle the high volume (and the few that could still crackled and such). The pair I got are really nice, because they go into the ear, which helps cut out most outside noise and sends the music directly into the ear (quite enjoyable quality). I know it's crazy and such, but I got used to it years ago when my father would blast his older metal/hard rock music (this being back when I was like 5 years old).

[Llorean]

It's not simply crazy. You will damage your hearing, and then music will start to sound worse as you lose frequencies. You'll also find yourself wanting to turn it even louder because it doesn't sound as loud any more, and it'll simply continue to get worse and worse.

Not to mention that almost no hardware performs well at maximum volume. You're nearly guaranteed to be introducing a large enough amount of distortion that in all honesty your bitrate is quite unlikely to matter terribly much. Earbuds at maximum volume are even worse.

[GodEater]

Can't speak for listening at maximum volume, because just the thought of it makes my ears hurt, but I was amazed at the difference between my sennheisers (CX-300) and the Shure E5s (I think that's the model they were) that Febs brought with him to London.

The Sennheisers are *pretty* good at blocking out surrounding background noise (this is called isolation), but the Shure's were flat out *amazing*. I couldn't hear anything from the pub we were in whilst I was trying them out, and it was *noisy* in there. And I most definitely didn't have the volume anywhere near maximum.

Still not going to drop $500 a pair for myself - but it was an enlightening experience!

[Chronon]

I got some ER-6 isolating, in-ear headphones and I love how much detail I can hear even at quite low volumes.  

Also, I am interested to hear that my Gigabeat can decode (some?) HE-AAC in real time.  I will have to rip some tracks to HE-AAC to test out the performance.  What is the best way to determine how quickly my player is decoding?

[Llorean]

Compile a custom build, adding the test_codec plugin to the SOURCES file so that it's compiled. Then use the that plugin (via the open-with context menu option) on a file of the format you wish to benchmark, if I understand how to use it correctly.

[Chronon]

Okay.  That sounds easy enough.  And thanks once again for such a prompt reply!

[Febs]

Can't speak for listening at maximum volume, because just the thought of it makes my ears hurt, but I was amazed at the difference between my sennheisers (CX-300) and the Shure E5s (I think that's the model they were) that Febs brought with him to London.

The Sennheisers are *pretty* good at blocking out surrounding background noise (this is called isolation), but the Shure's were flat out *amazing*. I couldn't hear anything from the pub we were in whilst I was trying them out, and it was *noisy* in there. And I most definitely didn't have the volume anywhere near maximum.

Still not going to drop $500 a pair for myself - but it was an enlightening experience!

The E500s tend not to isolate quite as well as the UM1s (which I also own) or the E2, E3 or E4 (which I've owned in the past).  I'm not sure why exactly, since I use the same tips on all of them.  My guess is that the E500 let's in more ambient noise through the body, which is fabricated through several pieces, while those other models are a single molded piece.  Nevertheless, the E500 blocks enough noise to allow me to hear my music very well without excessive volume.

[Chronon]

If this requires more than a single reply I will start a new thread in the  Getting Started and Compiling forum.  I checked out the source and was wondering which SOURCES file lists the plugins.  I looked at the SOURCES file in /rockbox/apps/ but I didn't see any references to the plugin sources in that file.  I could not find a SOURCES file in the plugins folder.

[Llorean]

There's a file, /apps/plugins/SOURCES, it's definitely there.
At least, it is in my copies of the source.