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Ipod with good headphones, what Codec and Bitrate???

Hi,
first time poster here.
I have an iPod running Rockbox which is almost full with m4a 256 tvbr files.
I want to fill more music, so i am thinking about transcoding my flac files with a lower bitrate, maybe with a different codec.
I just tried some ABX tests, and above 70kbit aac tvbr i was not able to hear a difference:-(Even the 32khz files sounded transparent to me:-(((
Maybe i was just using the wrong music. I listen to Jazz, RnB and Reggae.
A test file from the internet showed that i am able to hear up to 18khz.
I would just go ahead and use 128 tvbr aac, but i did a blindtest with a friend, and he is able to distinguish even 256tvbr music from flac.
So to those who can hear a difference above aac 128kbt tvbr:
What codec and bitrate would you use today, if space is limited, but still you want very very good quality?
aac 160? 192? 256? or maybe even a different codec?

Thank you guys!
 
The World Has Music For Those Who Listen

Re: Ipod with good headphones, what Codec and Bitrate???

Reply #1
Hi,

I think you gave the answer already by yourself:
Quote
I just tried some ABX tests, and above 70kbit aac tvbr i was not able to hear a difference:-(Even the 32khz files sounded transparent to me:-(((

Personally, I even use a lower setting: qaac 2.41, CoreAudioToolbox 7.10.9.0, AAC-HE Encoder, CVBR 48kbps, Quality 96
For me and my hearing that is perfectly fine.

What is good will also depend on your typical listening environment. And regarding transparency and blind tests: When you listen to music in normal conditions you are not conducting blind tests. Even thought you might be able to differentiate it doesn't mean that the output is necessarily bad. Once you reach the audible glitches you know that you have gone too low with your settings.

Quote
I would just go ahead and use 128 tvbr aac, but i did a blindtest with a friend, and he is able to distinguish even 256tvbr music from flac.

Was that a double blind test? If you read this forum you will find out that there is actually extremely few people that are able to differentiate at this level.

Re: Ipod with good headphones, what Codec and Bitrate???

Reply #2
Thank you for your answer.
so i am not the only one who is happy with such low bitrates...
The blindest with my friend was like this:
Flac and m4a same song started in sync.
Volume was identical.
Flac was played via DAC1, m4a DAC2.
Then i switched randomly between the sources and my friend was able to tell which one was m4a.
I then switched the DACs, same result.
We did it more than 20 times and with different songs, his rate was 100%!!!
I just sent him the link for Lacinato ABX/Shootouter.
can't wait to see his results after his vacation.
Will post them here if you want
The World Has Music For Those Who Listen

Re: Ipod with good headphones, what Codec and Bitrate???

Reply #3
AAC is quite good, so less than 100kbps bitrate is likely to sound transparent, especially for portable use.  I recommend using AAC-LC (and not AAC-HE as your iPod's CPU will require a lot more power to decode it) or possibly Vorbis which is similar to AAC but somewhat more power efficient in rockbox.

Re: Ipod with good headphones, what Codec and Bitrate???

Reply #4
Hi Saratoga,
thanks for your reply.
I am using dbpower amp on mac to transcode.
It has the apple aac and the m4afdk encoders.
Only the m4afdk has the ability to choose between LC and HE mode.
I don't know what the apple encoder actually uses, but it is much faster encoding.
I use quality 63 which is vbr around 128kbit.
I have the tarkan micro sd cards in my iPod and i put a huge chinese battery in, so energy consumption isn't a problem:-)
The World Has Music For Those Who Listen

Re: Ipod with good headphones, what Codec and Bitrate???

Reply #5
In XLD you can chose between LC and HE mode for CoreAudio AAC. I haven't done any speed tests for encoding though.

Re: Ipod with good headphones, what Codec and Bitrate???

Reply #6
In XLD you can chose between LC and HE mode for CoreAudio AAC. I haven't done any speed tests for encoding though.
Thanks,
I just tried, and HE is only optional up to 80 kbit, so I think with 128 in dbpoweramp it is LC. Strange that the file size differs between XLD and dbpoweramp.  I did not ABX between those, I am super sure I will not sense any difference.  I like using DB power amp, because It can batch convert my album art to jpg 300*300  during a AAC conversion, which is perfect for Rockbox on the iPod
The World Has Music For Those Who Listen

Re: Ipod with good headphones, what Codec and Bitrate???

Reply #7
I tried dbpower amp once, I couldn't even find a way to get MusicBrainz meta data instead of CDDB, which is a dealbreaker for me.

Re: Ipod with good headphones, what Codec and Bitrate???

Reply #8
Just go ahead and use what you think sounds 'acceptable' as you choose file size over quality. You can't have both without sacrificing something beyong a certain point.

Theres no point of using abx at lower rates as the *sole* factor here either; expecting one thing then getting another later on..

I tested casually LC /  AAC  (nero and faac) around 96k a few months ago and decided it would be a good replacement for mp3 (esp at similar bitrate ) should the need arise.
wavpack 4.8 -b3x6c

Re: Ipod with good headphones, what Codec and Bitrate???

Reply #9
"I have an iPod running Rockbox
What codec and bitrate would you use today, if space is limited, but still you want very very good quality?"

It boils down to the following...

-if your device has enough CPU then use Opus @ 96kbps and you might even find 64kbps to be a solid choice if your really trying to cram as much songs as possible on it while still maintaining a reasonable level of quality. I would avoid going lower than 64kbps with Opus.

-if your device can't play Opus files well due to lack of CPU then use Apple AAC @ 96kbps TVBR (128kbps TVBR tops). I would avoid bit rates lower than 96kbps with AAC (when I say AAC I pretty much always am referring to AAC-LC).

basically with any quality encoder use 96kbps (or 128kbps tops) and forget about it as you can't go wrong with either of those two settings for most people on your typical set of headphones, especially on-the-go. bit rates beyond 128kbps with AAC or Opus are a waste of space in my opinion. plus, with 96kbps you can't really squeeze much more songs on a device that uses 96kbps without dropping bit rate which with AAC I would avoid but with Opus I find 64kbps to be a usable option if trying to get maximum amount of songs on a device without quality taking too much of a hit.

I suggest Foobar2000 to convert your lossless files to Opus or Apple AAC (QAAC).

@shadowking

Quote
I tested casually LC /  AAC  (nero and faac) around 96k a few months ago and decided it would be a good replacement for mp3 (esp at similar bitrate ) should the need arise.

Yeah, there is really no reason to use MP3 anymore if AAC (QAAC) (or Opus) is a option given MP3 tends to be so-so in the 128kbps lower ranges where as AAC is still strong at 96kbps or 128kbps. like MP3 seems to need too much bit rate for a similar quality level. or look at it this way... how much bit rate would MP3 require to give a quality similar to Opus or AAC (Apple AAC) at 128kbps? ; LAME v2 (190kbps) or higher?
For music (especially on-the-go)...
-I suggest Opus @ 96kbps (or... 64kbps minimum, 128kbps maximum). *preferred choice*
-I suggest AAC(Apple) @ 96kbps (q45 TVBR) or 128kbps (q64 TVBR). *secondary choice*
-I use Foobar2000 (/w Encoders Pack etc) to convert FLAC to Opus/AAC(Apple).

 
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