Nnow that Itunes is for Winamp also, so i was wondering what file extension are you all using now.

i hate the .m4a extension, .mp4 is much cooler

but of course i am aware of the windows problem how to seperate audio-only from audio+video files
i guess to solve this we would need a mp4 version of the great oggprak tool, which can pass .ogg files with either audio-only or audio+video content to different players
grap the sources of oggprak here

maybe one of the great developers around can adopt this tool for mp4

The reason why Apple used M4A for audio-only streams is not Windows, but they disrecommend using anything but extensions for identifying file types on Mac OS X - for reasons of interoperability.

If you want a reliable way to distinguish your AAC files from your MPEG-4 videos and have them open in different applications on Mac OS X, they must have unique extensions. Luckily, this is pretty much the same way it is on every other OS out there

M4A.

Simply because you know what this is, imho, it should be something like this:

.M4A = MPEG 4 AAC Audio
.M4V = MPEG 4 Video
.MP4 = MPEG 4 Video + Audio


That way you'll atleast know what your getting..

In the case of just .MP4 - it can be a video file, it can be a audio file and it can be both video and audio in the same file, with the same extension. This will also be a problem for Audio/Video players, and associated file extensions.

Hi,

Yes, you're describing exactly the problem that Apple has run into because of the file extensions.

You can read a thorough and excellent explanation here:
http://www.arstechnica.com/reviews/01q3/me...metadata-1.html

In short, the "file extension" idea is a very bad design choice. File type metadata should be separated from file name metadata.

It's very sad to see Apple going the wrong route just because "everyone else is doing it"...

Cheers.

hehe, Just change .mp3 to .ogg or just delete the extension under Linux,
It will still tell u that .ogg you've renamed is MPEG layer-3

but if under Windows..................... u know what will happen

wtf does this mather?
get a life people.

I think .M4A is the best choice (used to think MP4) as it clearly differentiates to the various players that it is an MPEG 4 Audio (AAC) file. No video and no guessing on the part of the audio player app. Is M4A a registered international or MIME type standard anywhere (anybody know)?

Gooood point.

hm yes you are right

i will rename my mp4/m4a... damn all my files, it doesnt matter anyways, to .xyz now

anyone who knows a nice mass file extension changer which can change all extensions on my hd automatically

ren *.mp4 *.xyz /s

Pardon me, but I think it DOES matter. File extensions are a real problem nowadays.

If you turn off the display of file extensions in Windows, you can be fooled by VBS viruses that try to disguise as another type of file. And you'll be very confused when rogue software (like Real Player) steals your associations and changes their name.

If you turn them on for greater transparency, you run the risk of wiping them unintentionally when renaming a file. The problem is worse still if don't know/remember the original file extension, because then you won't be able to figure out how to open the file unless you identify it manually (or by trial and error).

We wouldn't have this problem with file extensions if file type metadata was stored in a different location and not shared with file name metadata.

Macintosh users are being forced into a problem that shouldn't have existed in the first place.

Cheers.

my god the bullshit continues.
Where did i state that extentions are unimportant??
I didn't.

I said it doesn't much shit weither people use .MP4 or .M4A.
Nothing you said makes a difference in that.

OK. Sorry, I misunderstood you. I thought you were referring to file extensions in general.

Regards.

thanks rjamorim, once again, what would i do without you

I don't know, but you could always try growing up

No, OS X doesn't need file extensions at all, as long as the application writes the metadata info. Even without an extension or metadata, the OS has ways of determining filetypes.

The reason Apple chose M4A is to maintain the naming convention of MPEG2.
M2A = MPEG2 audio
M2V = video
MP2 = audio + video

Makes sense, no? And it's a much more valid reason than picking extensions because they're "cool."

MP2 = MPEG audio layer 2.

The extension for audio+video MPEG2 streams is MPG or MPEG, same as MPEG1

I know that you can specify file type and creator, and I also know that this method - along with resource forks - is no longer used by Apple. They recommend that others move on as well, since they don't mesh well with other operating systems, other file systems and the BSD layers of Mac OS X. Thus my emphasis on reliable

Mac OS X, HFS and HFS+ supports files with two forks, and some metadata. In addition HFS+ supports an arbitrary amount of forks per file, and a good deal of metadata. However, since almost no other systems and file systems do this, and there isn't room for it within the standardised UNIX environment, it should be avoided.


Ah, if only it were so simple The convention seems to be:

• M2A = MP2 = MPEG-1 layer 2 audio
• M2V = raw MPEG-2 video
• MP4 = MPEG-4 file containing any combintion of MPEG-4 video, audio and systems tracks
• M4A = MPEG-4 file containing nothing but AAC
• M4V = raw MPEG-4 video

Ah, yes. I forgot MP2 is layer 2 audio, as rjamorin said.

Well, now we have the opportunity to clean up this mess with MPEG4. Let's get it right and use M4A for audio-only MPEG4 files.

Is it wise to restrict oneself to audio and video? What about video+subtitles or audio+chapters or, uhm, subtitles+chapters (is it even possible?)...

I agree with you negritot.

We should be using:

.M4A = MPEG 4 AAC Audio
.M4V = MPEG 4 Video
.MP4 = MPEG 4 Video + Audio
.M4P = DRM (Protected) content version of MPEG 4 Audio (Apple iTunes flavor)

I personally have had too many problems trying to play .MP4 audio files with various media players. Many of the them think it's a movie and try to play it as a video and error out. Thats why I like the .M4A extension.

I really believe in standards and using them to achieve broad compatibility between various hardware and software devices. Just like .MP3 is widely accepted and popular, .M4A/.MP4 should be broadly accepted and popular very soon.

With all the announcements in the last few days from Apple, HP, RealNetworks and IBM, it looks like MPEG 4 Audio will be with us for a while

The extension is .mkv

Anyway extensions are a good idea because they maximize interoperability between OSes which is infinately more important/useful than worring about file system esthetics.

What about something like:
.audio.mp4
.video.mp4
or something similar?

Some filesystems can't support two dot (.) file extensions like .audio.mp4

Others operating systems still in use like DOS and it's derivatives can't support extensions properly longer than 3 letter extensions. So 3 letter file extensions are here to stay...

I think ISO set a standard for a 3 letter file extension long ago in the initial CD-ROM format . I am not sure what color book the spec was (something like red book, peach book, etc.). This was back in the late 80s/early 90s I believe.

Well, I would say that extensions are a BAD idea that is unfortunately so widespread that you have no choice but to surrender to it in order to achieve interoperability.

Just because most people use it doesn't mean it's good.

The standard for Data CDs (CD-ROM) is the Yellow Book.

http://www.mediatechnics.com/yellowbook.htm

Thanks rjamorim for that! Yellow book it is...

I just remembered back to the late 70s, when I owned one of the early TRS-80 Model I 16K computers and I added the TRS-DOS disk operating system, the filenames had 3 letter extensions as well. In fact I just pulled this factoid up about TRS-DOS (circa ~1978):

In all the different TRSDOS type operating systems, there were several common features they all shared. Among these were: Disk drives were refered to as :0 to :3, file names were eight characters with an optional three character extension, the separator for the extension was a slash (/)

So it appears the 3 character file extension goes way back...

Conversely just because you don't find it elegant doesn't make it bad. However the system works well, and theres nothing to prevent OSes from expanding it in their own proprietary ways so i see no problem with it.

Also i disagree that a metadata system would be better for interoperability. It would be easily broken/made incompatable/extended by each vender. too easily. The fact that file extensions are so ridiculously simple is quite a virtue. Anyone can understand them and they are virtually impossible to break or make incomptabale.

Pardon me, what exactly is the advantage of storing the filetype metadata in some hidden place? It wouldn't help against a VBS virus, either.

What, besides the specific implementation, is different from hiding the extension?

Well, for MPEG-4 I'd say it's MP4. I don't see any advantage in using Matroska if your file is otherwise standards compliant.


Wouldn't most systems completely ignore anything prior to the extension? AFACT the main idea in using different extensions is to have the OS treat MPEG-4 audio and video like any other file...

Some of you may remember the Apple II DOS and ProDOS.

They both used the file type written alongside file size and date in the filesystem.

Having to use a block editor to modify a file type was awkward but it worked, many times I've appreciated the simplicity of using extensions, but not it's limitations.

And so the Mac inherited this method from it's older brother.

The current system allows you to accidentally wipe out the extension when renaming a file. In my opinion, that's a mistake. And hiding file extensions isn't a proper solution.

Take, for example, WinRAR: it sees .CAB .ARJ and .ACE files simply as "WinRAR archive". How are you supposed to distinguish one from the other if file extensions are hidden??

Sincerely, I don't understand how can you say that the current system "works well"



There's a VBS virus that tries to deceive the user by putting the ".mp3" extension just before the ".vbs" one. I've seen quite a lot of people who have been infected because they thought they were double-clicking an .mp3 song.

Cheers.

But that is WinRAR's fault, not the one of the system! What would hinder a program from screwing the metadata the same way in a Mac-environment?

I agree though, the conventions for naming file types in Windows should be better. (On the other hand, I never hide the extensions so I'm not really bothered.)


And they wouldn't click a file "new-cool-song (MP3)" with a music icon and a cryptic metatype (VBS)?

hmm that would be a text book :-)

Yes, I know it's WinRAR's fault. I was simply using that example (although there are many more, unfortunately) to point out that hiding extensions isn't the solution to the problem.



Well, perhaps. But maybe users wouldn't be so confused as they are right now when they see that some systems hide file extensions and some others don't. In fact, you have just admitted that you deliberately unhide file extensions.

Wouldn't you like better a system where there's no need to hide anything?

And why are file extensions hidden in the first place? Because they can easily be accidentally renamed by novice users. File extensions are just an ugly hack to a problem. And filetype metadata would have been a better solution.

Cheers.

Continuum, id3 tags are type of "hidden" metadata. Would you prefer that all the id3 data go into the filename?

I always thought, that metadata implementations are even more prone to hiding. How easily can you change the meta-filetype? That's one reason, why I like extensions.


Practical reasons forbid that. But then, if the tags are only part of the metadata (not the data itself, like it is now), they could easily be lost during a file transfer.

There is no general (OS independent) description tag with files, the only consensus is filename and date.


Anyway, that's not my point. The question was, if there had to be a practical difference between hidden extensions and metadata. I would think, that an OS could interprete file extensions as metatype and look like a native metatype implementation to the user.

But there is, even if it's not always used. A simple graphic file has a tag some examples GIF89a for GIF, JFIF for Jpeg, BM6 for BMP and audio RIFF for WAV etc.

If the program's parser intelligently identify the file by it's content and not by it's extension there'll be no problem reading the file.

Deciding the file type based on the contents of the file is not something you'd want your OS to do. There's too much that could go wrong...

This is not at the file system level! For the OS this is just data (although it's "metadata" from the user's point of view). See my argument against ID3 above.

The problem with attaching metainformation to a file is that it alters the entire concept of a file. On almost all systems, a file is a stream of bytes, the contents of which does not matter to the system. This means that by reading a file from the beginning to the end, you have an exact representation of the file.

The only system I know of which broke this model is the old model used in the old Mac OS. It was abandoned because it does not mesh well with the UNIX file model and causes all sorts of other problems - files must be archived when sent, etc. Any new file model should at least be kept backwards compatible with the traditional file representation.

The problem with attaching metainformation to a file is that it alters the entire concept of a file. On almost all systems, a file is a stream of bytes, the contents of which does not matter to the system. This means that by reading a file from the beginning to the end, you have an exact representation of the file.

The only system I know of which broke this model is the old model used in the old Mac OS. It was abandoned because it does not mesh well with the UNIX file model and causes all sorts of other problems - files must be archived when sent, etc. Any new file model should at least be kept backwards compatible with the traditional file representation.

I think Apple should be Spanked over this one, everyone knows .mp3 is audio, so .mp4 should also be audio - also audio files will out number video files by a large number it should have the 'better' extension - put video as .m4v

i dont see a problem in using .mp4 for both audio and audio+video i just need an oggprak-like tool

You and everybody else. I don't think that's a very sensible option.

or simply one player that handles both audio and video in a nice and usable way

The OS could include a little command-line utility to change the filetype metadata to whichever value the user wants to set.

Or you could always download a freeware utility to do just that. I'm sure somebody would make one freely available before long.

Then again, may I ask you how do you change the "last-modified" and "created" timestamps of a file? Those can't be changed at will by the user so easily.

Would you favour having timestamp metadata also appended to the end of the file name as well?

I think you are sacrificing a clean design in order to achieve "laziness" (I mean, come on, using a command line tool isn't that difficult!)

Cheers.

And expect every single user to switch to that player? Yeah, sure...