INTERACT FORUM

More => Old Versions => Media Center 11 (Development Ended) => Topic started by: shAf on July 15, 2003, 06:41:21 am

Title: what should I know about MP4?
Post by: shAf on July 15, 2003, 06:41:21 am

I was just reading about the FAAC project ...
http://faac.sourceforge.net/wiki/index.php?page=FAAC ... and elsewhere (Hydrogen Audio) about the current state of codecs ...
http://www.hydrogenaudio.org/index.php?showtopic=10313 ...

Despite subjective claims, quality vs file size, it could be argued MP4 (AAC) could become a popular format.  I was wondering to what degree MP4 is supported by MC9?  For example, any problems with tagging and library organization?  Any problems with analyzing the audio??  Any problems at all??

tia  :)

Title: Re: what should I know about MP4?
Post by: Sundog_AK on July 18, 2003, 11:10:27 pm

I have been fiddling with MP4 files (MPEG-4 AAC encoded music)  in MC 9.1.217.  But it is quirky and seems to freak out the view pane window in MC since MC treats it as a video file and not an audio file (but obviously no video).  You can't analyze the audio (at least the option is disabled when I select an MP4 file), since again MC treats as video.  

I don't know if I am that impressed with AAC overall.  It does seem to encode to smaller files than comparable bit rate in MP3 encoded files.  For example a Lame encoded MP3 file at 320 bit CBR was about 9100 KB and a MP4 file at 320 Bit CBR was about 8600 KB.  With the lack of "true" player support and little support in the utilities side (at least on PCs).  For me, I still use WMA files for anything that is "space" critical, plus wider support.  

My 2 cents.... ::)

Title: Re: what should I know about MP4?
Post by: kiwi on July 19, 2003, 07:44:54 am

Just out of curiosity, shouldn't the same bit rates equate to roughly the same file sizes?  i.e. if they are both encoding at 320kbps, should the files be approximately 320kb*the number of seconds?

I thought that the arguement for the MP4s was that they sounded as good as MP3s with a lower bit rate?  That the compression was better.

I however, have never really bothered to do the comparison.  For me, MP3s sound good for what I use them for...  I can't hear the difference in my car or through my iPod...  I find that anything over 140kbps or so is perfectly good for essentially background noise...   and when I want to really listen to music, I use APEs.  

kiwi

Title: Re: what should I know about MP4?
Post by: Buckaroo on July 19, 2003, 09:05:22 am

I like AAC quite a bit. AAC is the standard chosen by Apple for its iTunes store, So any music that you buy there is encoded as AAC.

I've been checking it out on one of my Macs, and the sound quality at, say, 128 is clearly much fuller than MP3. Now, my library is currently LAME MP3 VBR High (averages about 190kb/sec for most music), and the differences between AAC and a well encoded VBR MP3 file is much subtler, but still there.

I haven't even tried playing with AAC on MC yet, so I can't speak to JRiver's implementation. I'd bet that MC will offer good AAC implementation before Apple's store is available for PC users.

Title: Re: what should I know about MP4?
Post by: MachineHead on July 19, 2003, 09:31:19 am

Quote

I'd bet that MC will offer good AAC implementation before Apple's store is available for PC users.

Don't bet on it Buckaroo. These codecs are not true open source projects regardless of what SF says. They are for developmental study only. J River isn't about to add these anytime soon. You try and fight Dolby and let us know how things go...

The licensing is the real hang-up here. Big dollars means no time soon.

Title: Re: what should I know about MP4?
Post by: Buckaroo on July 19, 2003, 02:12:39 pm

I actually deal with some of the licensees in question as part of my job, and although you are certainly correct about the mess that AAC today, this will be streamlining in the future.

Basically, as AAC gets more popular, the licensing will get less restrictive. Indeed, a number of formally restricted components (such as AAC streaming) have already become openly available.

This link is a good primer, although it floats over some of the issues I mention:
http://www.vialicensing.com/products/mpeg4aac/licenseFAQ.html

However, upon reflection I have to concur that my initial MC integration estimate was probably way too optimistic.

Title: Re: what should I know about MP4?
Post by: iCamp on July 20, 2003, 05:17:20 pm

Perhaps you guys can explain this to me:

If AAC licensing is such a problem why is it that free players like QCD, Foobar, Winamp, among others can offer free plug-ins for ACC?  I don't get it.  Obviously Dolby isn't going after these authors...what's keeping the development community from writing a plug-in for MC??

Title: Re: what should I know about MP4?
Post by: MachineHead on July 20, 2003, 07:23:32 pm

They use the study codecs. And if you have a good look around, you'll find most are hosted from a site in Brazil. Patent laws here do not apply there apparently.

Title: Re: what should I know about MP4?
Post by: iCamp on July 20, 2003, 07:38:40 pm

What's a "study" codec?

I checked a few of the plug-ins and they are hosted by US based servers.  I even checked for re-directs.  The QCD plug-in, the dBPowerAmp plug-in, two different Foobar plug-ins and a WinAmp plug-in I found all fall into this category.

It's my guess that either Dolby doesn't care since none of these applications are making any money or the whole ACC licensing thing is just overblown.