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1
OK, the scheme in which these documents are filed is a bit strange, and it seems there's lots of duplication going on.
All files have been updated or at least checked on March of 2017, so they're not that old, or at least not that much out of date.
The specification documents are in .DOC (Microsoft Office 2003) format, out of all things - I can't even...

  • 26.273 contains source code an MSVC project files, and a compiled library and an encoder and decoder executable. Each have the suffix "_fx", which would be consistent with it being the fixed-point variant. While the .DOC file has been last changes in March 2017, the source code hasn't been changed since 2005 or 2006 depending on file.

  • 26.274 contains test vectors, as well as compiled versions of the encoders, decoders and libraries as well as companion programs in several directories (I don't quite understand the logic behind that, except perhaps convenience?). Both "_fx" and the floating point variants are scattered in various places here. No source code, though. The samples are interesting, though. All files, including the test samples are from 2005, except for some compiled files, which are from 2006, only the documentation has been updated in March of 2017.

  • 26.290 only contains a .doc document *sigh*, which explains the signal processing part. Transfer functions ( H(z) = ... ), and mathematical models are explained here, as well as a couple block diagrams, bode diagrams, and things like file formats are explained here as well. Last changed in March 2017.

  • 26.304 is very much like 26.273, it contains sourcecode, MSVC project files, a bit of documentation and compiled versions of the DLL, and encoder and decoder .EXE files. These are the versions without the "_fx" suffix in the name, which is consistent with what is mentioned in the 3GPP portal page, describing this as the floating point variant of the codec. Most of this code is slightly older, from 2004, with the latest changes to some of the source code in 2006. The documentation has been touched in March 2017.

It's hard to say if and what was changed in the main .DOC files warranting an update. For all I know, it might've been no changes at all, etc.

In general, there doesn't seem to be much maintenance going on. I can only imagine, that the reason why the fixed point variant and the floating point variant are kept in individual repositories, is just so they can be filed individually. There's really no reason not having both variants in one repository and simply have compilation rules for each variant. At the same time, it's just a matter of a couple functions to which this difference is pertaining. So they could be kept next to each other without confusion, etc. Maybe making licensing easier was another reason.

The repository mentioned in jensend's post, is essentially the floating point variant, re-uploaded and modified for compilation with autotools. I'll take a look at it later, perhaps.

Porting code from MSVC to GCC I find atrociously annoying, especially if the IDE is >10 years old...
2
Audio Hardware / Re: Interview Time
Last post by evgenetic -
i see that adding the distortion isn't difficult at all, but how would one go about replicating the same "model" of distortion from one of his tube amps for example, how do you reverse engineer it? i guess harmonic distortion can be quite predictable, but from what i understand IMD may only enter audibility with some particular signals, and thus very individual to every amp.
3
3rd Party Plugins - (fb2k) / Re: foo_uie_lyrics3
Last post by XoRRoX -
Hi everyone,

I have the feeling that the developer isn't supporting the plugin anymore, but maybe someone else can help me.

When I listen to streaming radio, the Artist is not specified in the respective field, but the Artist + Song Title as a whole in the Title field; "The Cure - A Forest" and thus the plugin doesn't find the lyrics.
Does someone know of any way I can feed the plugin the Artist and Song Title in the fields it needs?
 
Thanks in advance for any help.


Ok, I researched and dove into title formatting, which works in the Lyric Show 3 fields. Here's what I came up with:
 
I test if there's a "-" in the title, which the station puts inbetween the artist - songtitle in the %title% filed. When it contains the "-", I extract everything before it and return it, for the Artist parameter box. If not, I just return %artist%. Same principle for the Title config box, but then everything after "-".
 
So:
- Artist   : $ifgreater($strstr(%title%,-),0,$trim($left(%title%,$sub($strchr(%title%,-),1))),%artist%)
- Title   : $ifgreater($strstr(%title%,-),0,$trim($right(%title%,$sub($len(%title%),$strchr(%title%,-)))),%title%)
 
I know it's not perfect for titles of songs containing a "-", but I cannot think of another way and accept those rare (?) cases.
 
Hope it's also helpful to someone else.
 
Cheers.
4
General Audio / Re: Powering Up Audio System
Last post by Arnold B. Krueger -
You might want to use a scope and monitor AC line current under demanding audio peaks to see if the amp ever spikes as high or higher than the startup cap-charge spike.

Ever actually do this?   The results are usually very stunning for what they don't show.

Quote
I'm not aware that inrush current limiters are common in audio power amps.

The basic design of a naively designed simple linear power supply creates high inrush currents.  Switchmode power supplies which are becoming more common can accomplish this with very little expense or trouble.

In a simple linear power supply the inrush current is limited by things that are always there to some degree, such as the maximum saturation current of the power transformer, the CD resistance of its windings, and the ESR of the rectifiers and filter caps.

As long as power amps are designed to satisfy imaginary requirements created by audiophile myths such as all channels driven power ratings, there is a strong exposure to excessive inrush currents.

One simple solution to this problem might be to use a more realistically sized power amp to drive the subwoofer.

BTW turnon thumps and inrush currents need not have any relationship to each other.  They are separate problems that can easily have separate causes.


5
...But if your home theater speakers are matched or were sold as a set, you shouldn't need to adjust the balance/levels.
I do not wish to hijack the OP's thread, but my query may also assist him. The above quote from DVDdoug stirred me to post here in this thread.
I have a 7.1 AV amp (Yamaha DSP-AX757SE) with 5 matching speakers (4 x Mission 751, and Mission 75C centre) hooked up so it is a 5.0 setup. My room is far from ideal. I never bothered setting up the calibration mic, and left everything flat/default with regard to timings and levels. My experience is satisfactory. Seating is not arranged as a theatre, so there is no sweet spot. My thought was that if I am sitting nearer to left rear, it would be quite natural that I should hear a bit more of the left rear than if I was say sitting nearer front right.
Is this a reasonable view to take with matching speakers, or would I and the OP really benefit from doing some room calibration?

http://www.roomeqwizard.com/help/help_en-GB/html/iseqtheanswer.html#top
6
Support - (fb2k) / Re: Library update after file rename?
Last post by mefoo -
File change monitoring doesn't tend to work that well over remote shares. You can also right click on a media library path and force an update.

Didn't know about that context menu, so thanks.

OTOH I thought I'd read somewhere that foobar would be aware of file operations like renaming carried on by itself, so I thought maybe the library would keep track, rather than rely on the monitoring for a change.
7
If you just want to set/match the levels from the 5 speakers without tweaking equalization/frequency response, you don't need anything calibrated.  All you need is something with a level meter that makes repeatable measurements.    You might need to run a recording application on your laptop or phone to get a meter on the screen.  

Then, run your white noise or pink noise test files.  Noise is harder to measure because it's "unstable", but a single-frequency tone will be affected by reflections in unpredictable ways and your overall volume-balance may be off.

But if your home theater speakers are matched or were sold as a set, you shouldn't need to adjust the balance/levels.

And, you might want to adjust the subwoofer to your taste.

If it were only true. :-(
8
hi all, know this is kinda inactive. I don't even use windows but I still use foobar pretty much on account of this and other game related plugins. one thing I remember though was that gep used to have more advanced controls? like you used to be able to mute specific tracks in the song emulation. is that no longer a feature?

it's be really handy for recording specific elements...


anyway, it's still great, so thanks kode54 for your hard work!
In foobar menu, check View->GEP control. If the emulation format supports channel muting and stuff, that's where the controls are going to be.
9
3rd Party Plugins - (fb2k) / Re: foo_youtube
Last post by 3dyd -
Could not reproduce the crash. Crash report would be helpful (files *.dmp and *.txt). You can send them via PM or directly to fy[at]3dyd.com
10
hi all, know this is kinda inactive. I don't even use windows but I still use foobar pretty much on account of this and other game related plugins. one thing I remember though was that gep used to have more advanced controls? like you used to be able to mute specific tracks in the song emulation. is that no longer a feature?

it's be really handy for recording specific elements...


anyway, it's still great, so thanks kode54 for your hard work!