mp3 and Variable BitRate

Post by **hubird** » Sun Dec 08, 2002 11:19 pm

This is about mp3 types of quality.
I normally use 44.1 kHz, 256 kbits/sec, Variable BitRate, stereo, Highest Quality.
BUT... sometimes or even often I get a small gap of about half a second in my mp3 file.
If I retry, the gap comes up at the same point of the song.
I sometimes noticed this gap with uploads of others here on planetz.

I fiddleled around with the mp3 parameters, specially the kbits/sec, but the only thing that can prevent this gap was switching to Constant BitRate.

In terms of quality it doesn't matter, but the big difference AND disadvantage is that without Variable BitRate the mp3 file gets two times bigger!!

Does anyone knows how I can prevent the gaps without disabling the Variable BitRate funktion??

May be John can tell us more about this

It does matter, coz halve the uploaded files saves a lot of memory.

There is something that is related to this.
I recently changed something in the player which playes the planetz music songs.
Till that time I always got a big white screen with the small flat player window (I'm on mac, so it must be quicktime).
After I changed something (dunno for sure what parameter), I could keep seeing the planetz site instead of the all screen Quicktime window.
Nice.
BUT...I now have to wait till the whole file is streamed down before I can start listening.
I checked all the Quicktime preferenses, also the M.E. preferenses, but I cannot get it changed back.
Other sites with mp3 streaming service yet show me the download-while-listening player.
There must be some coocky active??
I dunno mutch about these things, anyone who can shine his light on this?

It does matter in my case, coz a 2 times bigger file takes mutch more time to listen to...

_________________
Let There Be Music!

[ This Message was edited by: hubird on 2002-12-09 00:08 ]

samplaire · Post by **samplaire** » Mon Dec 09, 2002 4:08 am

Hi Huub,

if you use IE then look in the 'file helpers' part of the preferences. you can change your default mp3 player there I belive (though I'm not 100% sure).

at0m · Post by **at0m** » Mon Dec 09, 2002 7:21 am

You guys on mac have Media Player with IE?

Then try MP-> Tools -> Options -> file types

ernest@303.nu · Post by **ernest@303.nu** » Mon Dec 09, 2002 8:17 am

Huub, are you Lame already?

http://philippe.laval.free.fr/DropMP3/index.html

Mac-implementation of the very best encoder for mp3, sound-quality wise (I'm on Win so haven't tried the mac-version, but should work)

samplaire · Post by **samplaire** » Mon Dec 09, 2002 8:30 am

On 2002-12-09 07:21, at0mic wrote:
You guys on mac have Media Player with IE?

We even have our ... eeehhrr... WinAmp

I wouldn't suggest MP as a default player because it maks a mess in IE and becomes a default app for some strange suffixes like .bin (and annoys each time you want to download such file) - bin is binary archive and should be opened with Stuffit Expander or similar. So MP yes - but be carefull setting suffixes.

[ This Message was edited by: samplaire on 2002-12-09 08:31 ]

samplaire · Post by **samplaire** » Mon Dec 09, 2002 8:34 am

On 2002-12-09 08:17, ernest@303.nu wrote:
Huub, are you Lame already?
Mac-implementation of the very best encoder for mp3, sound-quality wise (I'm on Win so haven't tried the mac-version, but should work)

We on Mac have a free mp3 ripper/encoder directly from Apple - iTunes - it's good but I don't know if it's better from the one you mentioned - have to try.

Post by **hubird** » Mon Dec 09, 2002 9:18 am

thanks all of you.

Sam, I checked the Files/cookies prefs already, but there isn't mentioned a planetz cookie to delete, and other stuff doesn't make any difference.

Also it's just in combination with our planetz site that Quicktime doesn't play while downstreaming... strange isn't it.

I think the solution is in the MIME prefs of Quicktime, I'm gonne try that again tonight, but I even don't know what MIME is other than an art of imagination

At0m, yes I have WinAmp, but not as default player.
I think the mac version is stripped down, coz I can't find any path you mention, but maybe I should update (have v.0.71 alpha, readme says it supports mp3 with VBR).
Also I had strange behaviour with WA, as Sam points out, thanks anyway.

Ernest, I'll try this one, thanks.
On the other hand, for mp3 encoding I use Medea Cleaner v.5.0, I think it's a hi-end tool.
But I'll have a look how Lame I can get

Open question: does everybody use/not use Variable BitRate (VBR)?
Saw someone lately suggesting you shouldn't use it.
But it halves the file length, so...

samplaire · Post by **samplaire** » Mon Dec 09, 2002 9:36 am

On 2002-12-09 09:18, hubird wrote:
thanks all of you.

Sam, I checked the Files/cookies prefs already, but there isn't mentioned a planetz cookie to delete, and other stuff doesn't make any difference.

I think the solution is in the MIME prefs of Quicktime, I'm gonne try that again tonight, but I even don't know what MIME is other than an art of imagination

I have to try it

At0m, yes I have WinAmp, but not as default player.
I think the mac version is stripped down, coz I can't find any path you mention, but maybe I should update (have v.0.71 alpha, readme says it supports mp3 with VBR).
Also I had strange behaviour with WA, as Sam points out, thanks anyway.

I think Atom mentioned Windows Media Player (MP) available on M$ site for Mac. I said we have also WinAmp (which i use sometimes especially to play mp2 songs which are standard at the radiostation we are part of).

Open question: does everybody use/not use Variable BitRate (VBR)?
Saw someone lately suggesting you shouldn't use it.
But it halves the file length, so...

Hmmm...... I don't know

I don't use it but I can't say why. I just don't belive in it as I don't belive in mp3 at all (but forced to use it I'd rather not use the VBR)

[/quote]

ernest@303.nu · Post by **ernest@303.nu** » Mon Dec 09, 2002 10:16 am

I'll just keep promoting Lame

because I like to hear the best quality possible when downloading mp3s...
Things will get more complex as I'm digging deeper, but you can drop-out any time you want!

There are 2 major mp3 encoding engines: the commercial Fraunhofer (also known as fhg), which is the oldest and used in most commercial and shareware products, and Lame, a free and open source cross-platform implementation. Lame is constantly being improved and uses different psycho-acoustic models and filtering than fhg, as well as advanced vbr/abr frame bitrate prediction. To *my* ears, lame-encoded music sounds more transparent with more defined stereo image for the high frequencies and less artifacts....
BUT....
the Lame encoder accepts *many* parameters to tweak things, and the wrong settings might undo the benefits over fhg.
And that's where the so called 'front-ends' (like dropbox, winlame etc) kick in: they offers a set of pre-defined parameters to drive the (often command-line) lame-encoder.
My Lame settings of choice for most styles of music, at any bitrate:
Quality Q0, joint stereo, no lowpass-filtering (many encoders filter at 19500Hz by default, but I'm one of the few hearing the difference).
When doing VBR I like the min160-max320-setting for most music.

Using stereo instead of joint stereo sometimes reduces artifacts when using VBR or ABR (at the expense of file size), especially when encoding older jazz music! (the slight wow/flutter of the original tapes do strange things to non-harmonic contents of the ride cymbals when encoded... apparently very difficult for both fhg en Lame at VBR and ABR)

Another advantage of Lame is the ability to encode 24-bit Wav-files. The full dynamic range of the file is then used to calculate the optimal contents for every single mp3-frame! However, being optimized for 16-bit-alike playback the dynamics of the resulting MP3 most often still does not exceed 16-bit, but still, this might be preferable to a dithered-to-16-bit WAV file, where the carefully added dithering noise containing subtilities probably will end on the virtual junkyard when the mp3-encoder decides it's "inaudible because it's masked by other frequencies".

A final Lame-related story is high-bit mp3 *decoding* through the opensource MAD project. The theoretically optimal decoding is rendered on a 32-bit or 24-bit grid instead of 16 bit.
I'm using the Mad-plugin for Winamp that claims 24-bit accuracy, but some tests show this particular plug-in's accuracy is actually 19-bit using a 24-bit soundcard, and 17.5 bit (through the plugin's built-in dithering) with a 16-bit output. Still.... it sounds better ('rounder') to my audiophile ears! Especially low-volume high-frequency contents and stereo image.

Ogg and AAC are still better-sounding than mp3 IMHO, but they're currently too little supported for distribution-purposes

Lame http://lame.sourceforge.net
Mad http://www.mars.org/home/rob/proj/mpeg/

samplaire · Post by **samplaire** » Mon Dec 09, 2002 10:44 am

Double post. look below

[ This Message was edited by: samplaire on 2002-12-12 08:50 ]

samplaire · Post by **samplaire** » Mon Dec 09, 2002 10:44 am

Thanks for the deep explanation, Ernest. however I still don't know the difference between stereo and joint stereo parameter (perhaps it's due to my poor English?)

[ This Message was edited by: samplaire on 2002-12-09 10:45 ]

Post by **hubird** » Mon Dec 09, 2002 12:08 pm

On 2002-12-09 09:18, hubird wrote:
At0m, yes I have WinAmp, but not as default player.

I'm messing up... I surely meant the Win Media Player...thanks Sam for notifying.

ernest@303.nu · Post by **ernest@303.nu** » Mon Dec 09, 2002 12:59 pm

samplaire: no matter how poor your english

, I didn't explain the difference between 'stereo' and 'joint stereo' in my posting!
Simply put: "joint stereo" takes advantage of the fact that the left and right channel most often partly contains the same information, and emphasizes encoding of the *differences* between channels, as well as encoding the 'common' part between the channels.
However, sometimes the channels differ too much, or in a very subtle yet noticeable way, and then it's better to encode using the 'stereo' mode, which emphasizes on encoding left and right channel as seperately as possible.
As a result from this last type of encoding, more bits are used for both seperate channels, because there's less 'common' data to rely on. The result is, that there are less bits available for other tasks within the encoding process (possible resulting in *other* artifacts at a given *constant* bitrate), or a bigger file size for VBR files.

As always the truth is more complicated (for example depending on the applied (psy-acoustic) model the encoder might decide to encode certain frames using jstereo, stereo or m/s stereo no matter what option you choose, if it thinks that doing so will benefit accuracy)
If you like this kind of stuff (like me!) there's plenty of advanced information to read on the internet

[edit] changed a couple of words, hope it will be clearer now... [/edit]

[ This Message was edited by: ernest@303.nu on 2002-12-09 13:56 ]

Post by **hubird** » Mon Dec 09, 2002 1:01 pm

thanks Ernest, great stuff you told us, though I hardly know what you're talking about.
I will check the links you gave first.

In the readme of Media Cleaner I found this:
Microsoft's Windows Media Player for Macintosh may have timing issues with Open URL events, so you may wish to avoid using these events with files intended for viewing on the Mac. Additionally, Chapter events are not supported in the first three seconds of Windows Media files when created on a Mac.
For what's worth...

ernest@303.nu · Post by **ernest@303.nu** » Mon Dec 09, 2002 2:00 pm

Huub: apart from pointing to usable downloadable software, these links aren't exactly a source for beginner-level information

When I find a such a link, I will post it on the forum.

Post by **hubird** » Mon Dec 09, 2002 9:09 pm

great, ernest...

Post by **hubird** » Tue Dec 10, 2002 12:27 am

this is a start I found:
http://www.mp3-tech.org/

ernest@303.nu · Post by **ernest@303.nu** » Tue Dec 10, 2002 3:38 am

Good site! Clear explanation of the basics

ernest@303.nu · Post by **ernest@303.nu** » Tue Dec 10, 2002 8:31 am

http://www.mpeg.org/MPEG/audio.html contains a wealth of (often hi-tech) links on mpeg-related audio compression

samplaire · Post by **samplaire** » Thu Dec 12, 2002 8:49 am

I found this on Ogg Vorbis: http://www.xlr8yourmac.com/audio/index.html . It's all regarding Macs but the info is unisex

The site look like it's updated frequently so if the link doesn't contain the text about Ogg Vorbis then look at the bottom of the site for back issues links.

[ This Message was edited by: samplaire on 2002-12-12 08:59 ]