AAC/M4A Encoder / Decoder Plug-in : Quality and reliability?

by **Jon EP** » Wed Jun 01, 2011 4:53 am

Thanks!

by **nohitter151** » Tue May 31, 2011 1:11 pm

Jon EP wrote:Hi,

After reading this, I still have a question about transcoding from M4A. I have files that were ripped as M4A variable bit rate (I thought they were ripped as lossless, but wouldn't they have been alac then?). I want to transcode them to FLAC with 0 compression. Is there a limitation on the AAC / M4A encoder that will prevent MediaMonkey from transcoding without a loss in quality? Or will the quality of the FLAC be subject to limitations? Basically, whatever the quality of the M4As, lossless or lossy, will the same quality level be maintained on the FLACs?

Thanks.

1. There is no ALAC extension, ALAC files usually have the .m4a extension
2. No
3. The FLACs will be of the same sound quality as the original file
4. Yes

by **Jon EP** » Tue May 31, 2011 12:54 pm

Hi,

After reading this, I still have a question about transcoding from M4A. I have files that were ripped as M4A variable bit rate (I thought they were ripped as lossless, but wouldn't they have been alac then?). I want to transcode them to FLAC with 0 compression. Is there a limitation on the AAC / M4A encoder that will prevent MediaMonkey from transcoding without a loss in quality? Or will the quality of the FLAC be subject to limitations? Basically, whatever the quality of the M4As, lossless or lossy, will the same quality level be maintained on the FLACs?

Thanks.

by **Metazargo** » Sat Mar 12, 2011 7:59 am

I started to use the latest MediaMonkey AAC Plug-in, where I ripp to M4A, because when I use AAC MM can't update the tags (see here http://www.mediamonkey.com/forum/viewto ... 68#p287452).

I use as the format M4A with variable bitrate VBR and quality 50% = ~177kbps.

But in the properties of the files, it says 'VBR: No'. Is this correct, what is wrong?

Thanks for advice.

by **Peke** » Thu May 13, 2010 6:12 pm

My choice would be FLAC due the Format nature (Multi channel HD format Audio 24/192), Great Tagging support, Native CUE support (not yet in MM), Free Codec and Most new hardware devices (I mean quality devices not low cost devices) support it.

by **Teknojnky** » Thu May 13, 2010 2:25 pm

I don't see where they disagree, most should find transparency between v2 and v5. It all depends on your ears, equipment and environment.

using the old alt-preset naming, alt-preset-insane = 320, alt-preset-extreme = v0, alt-preset-standard = v2

besides, if there is any doubt in transparency, you should simply go ABX or go lossless.

by **nohitter151** » Thu May 13, 2010 2:02 pm

Teknojnky wrote: I don't think thats quite accurate, lame should be transparent for most people and most audio types somewhere between v2 and v5.

V0 is considered way overkill thus the 'extreme' nickname.

when in doubt, ABX it and prove it to yourself that you can hear the differnce.

That doesn't seem to match up with this: http://wiki.hydrogenaudio.org/index.php ... _answer.29

by **Teknojnky** » Thu May 13, 2010 1:37 pm

I agree that m4a files can be very confusing, and there is no indication within MM itself other than the bitrate.

You probably already know this, MM can PLAY both lossy and ALAC files, it just can not encode ALAC files.

From my own research, I re-iterate the suggestion that you should look closely at dbpoweramp reference for ripping and encoding to ALAC. Additionally, it can add a bunch of detailed columns and/or info to explorer pop up, so you can see easier into the details of the files (codecs, lossy/lossless, etc).

You can then continue to manage and play your files with MM, along with sonos and itunes when necessary.

by **matthewschenker** » Thu May 13, 2010 11:58 am

Hello,
Thanks everyone for jumping in.

Yes, I do understand the idea of lossy versus lossless. My confusion was that I had been working under the assumption that m4a is lossless. Then I learned that m4a is just a "container" which could be either Apple Lossless or AAC, the former being lossless and the latter being lossy. In other words, if you have a buynch of m4a files, you can't say whether they are lossy or lossless unless you further specify whether they contain AAC or Apple Lossless files. And you can't figure that out without some kind of decoder. OK, that's confusing, don't you think?

Regarding sound tests: I can indeed hear the difference between 256 mp3 and lossless files. There is no doubt about that. This is the main reason I made the switch originally away from mp3 files: when I played them on my home system the quality was clearly worse.

I think I understand the whole m4a/Apple Lossless issue now.

by **Teknojnky** » Thu May 13, 2010 11:56 am

nohitter151 wrote:
Lowlander wrote:It's not equivalent, because one is lossy and the other is lossless. Flac would be equivalent.

But, you should conduct listening test. There are many sources online that claim that double blind testing has show that most people couldn't differentiate a MP3 from a WAV. (I don't remember at what bitrate MP3 this difference is unnoticeable).
for LAME mp3 its generally cited as the v0 vbr setting (or about ~245 kbps).

I don't think thats quite accurate, lame should be transparent for most people and most audio types somewhere between v2 and v5.

V0 is considered way overkill thus the 'extreme' nickname.

when in doubt, ABX it and prove it to yourself that you can hear the differnce.

by **nohitter151** » Thu May 13, 2010 11:30 am

Lowlander wrote:It's not equivalent, because one is lossy and the other is lossless. Flac would be equivalent.

But, you should conduct listening test. There are many sources online that claim that double blind testing has show that most people couldn't differentiate a MP3 from a WAV. (I don't remember at what bitrate MP3 this difference is unnoticeable).

for LAME mp3 its generally cited as the v0 vbr setting (or about ~245 kbps).

by **Lowlander** » Thu May 13, 2010 10:35 am

It's not equivalent, because one is lossy and the other is lossless. Flac would be equivalent.

But, you should conduct listening test. There are many sources online that claim that double blind testing has show that most people couldn't differentiate a MP3 from a WAV. (I don't remember at what bitrate MP3 this difference is unnoticeable).

by **Teknojnky** » Thu May 13, 2010 10:35 am

matthewschenker wrote:I've done a lot of reading on the subject, but I still cannot determine whether m4a is equivalent in quality to Apple Lossless. I'm not asking if it's the same -- just whether it is equally as good. I ask because the bit rate in MediaMonkey m4a is a lot lower than the bit rates for Apple Lossless. Maybe that's not so important?

Short answer, NO.

Long answer, it depends on *YOUR* EARS. When in doubt, decide for yourself with double blind ABX testing. FOOBAR has an excellent ABX component, you can compare a ALAC or WAVE or other LOSSLESS file with an AAC/m4a, mp3 or whatever else, to see if you can actually hear a difference.

But understand this, M4A is just a container format, standard M4A AAC files are LOSSY.

M4A files encoded with ALAC are LOSSLESS.

if you do not understand the difference between LOSSY and LOSSLESS then I suggest you start @ http://wiki.hydrogenaudio.org/index.php ... best_codec and read the articles about LOSSY and LOSSLESS codecs.

by **matthewschenker** » Thu May 13, 2010 10:13 am

Peke,
I understand. No problem.

My concern is maintaining a library with lossless music in case I need to burn CDs.

Even more important, I run the Sonos system in my home, and for that I like to stream CD-quality music. Apple Lossless has been the format of choice, mainly because I was using iTunes and Sonos picks it up nicely.

I've done a lot of reading on the subject, but I still cannot determine whether m4a is equivalent in quality to Apple Lossless. I'm not asking if it's the same -- just whether it is equally as good. I ask because the bit rate in MediaMonkey m4a is a lot lower than the bit rates for Apple Lossless. Maybe that's not so important?

Thanks for helping!

by **Peke** » Wed May 12, 2010 5:26 pm

To clarify bit more. There is no free or reasonable priced ALAC encoder library to be included in native plugin and we certainly do not want to double plugin price just to include ALAC support. Again Apple do make things harder for us as they are holders for Patent and licensing.

AAC/M4A Encoder / Decoder Plug-in : Quality and reliability?

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