Quality and BitRate of SAT Recordings posted on tribal mixes

SpasV V.I.P. on March 9th, 2007 / post 16919

There is one more statement I need to address.
“hec aac+ v1 is a low bitrate codec! only developed to serve acceptable quality at the lowest bitrate possible. i think u have missed that point. it is the main reason for developing such codecs!”
I am sorry, I have to object that as totally wrong.
First, when we are talking about XM Sat Radio we have to think about aac+ v2, not acc+ v1. (It is enough for me to go by another's mistakes.)
Second, I am not a sound compression expert, I am not prepared to discuss a topic such evaluation of HE-AAC v2 - the MPEG-4 High Efficiency AAC v2 profile.
So, I can not go in details and I can not make statements like “hec aac+ v1 is a low bitrate codec! only developed to serve acceptable quality at the lowest bitrate possible”, which of course is not true at all.
What I can is to refer to the article I have already mention: “MPEG-4 HE-AAC v2 — Audio Coding For Today's Digital Media World” by Stefan Meltzer and Gerald Moser. ” (EBU TECHNICAL REVIEW – January 2006)
The say “HE-AAC v2 has proven in several independent tests to be the most efficient audio compression scheme available worldwide. Nothing about “a low bitrate codec” but “the most efficient audio compression scheme available worldwide”.
Further: “This article gives an overview of the standardization, its technical components and compression efficiency, and provides an outlook on the future potential of ongoing development work.” So, read it.
And further: “Considering the fact that the quality of compressed audio signals scales with the bitrate, the following interpretation of the available test results can be made.
Combining AAC with SBR and PS into HE-AAC v2 results in a very efficient audio codec, providing high audio quality over a wide bitrate range, with only moderate gradual reduction of the perceived audio quality towards very low bitrates.” And “Even at bitrates as low as 24 kbit/s, HE-AAC v2 still produces a quality far higher than that of any other audio codec available.”
The entirely wrong impression of a “a low bitrate codec” arises from the fact that at a low bitrate “HE-AAC v2 still produces a quality far higher than that of any other audio codec available.” No codec exist that can be even comparable at low bitrate.

Skype:spas.velev

SpasV V.I.P. on March 9th, 2007 / post 16921

@TomMix
Maybe I could guess where the misunderstanding of the acc+ v1 comes from but it is better for you to find it by yourself.
Here is a reference from https://www.codingtechnologies.com/products/layer2.htm:
“In most cases, the overall system (digital broadcast systems) capacity is fixed, so there is no chance to extend the number of transmission channels easily.
This is exactly where SBR (Spectral Band Replication) comes into play. By adding SBR to MPEG Layer-2, the bit rate of a particular audio service can be reduced up to 50 % by maintaining the audio quality. Thus, the amount of services in a certain system can be increased by remaining backward compatibility to MPEG Layer-2 decoders - non-SBR receivers may stay in use!”

Skype:spas.velev

TomMix 3daywarning on March 9th, 2007 / post 16951

1st. im that tired after that day so i keep my info short
2nd. ur link to codingtechnologies reference isnt working
and last but not least:
please read about SBR to realize its artificial syntetic highband at the endpoint POSTPROCESSING
please read about AAC to realize its for low bandwidth

lol read this: xm facts

"Official XM Radio WebSite" wrote:
XM searched the world for the best sound quality technologies and found them in customized CT-aacPlus audio encoding with Neural Audio optimization, which provides superior sound quality remarkably close to Compact Disc.

The key to XM's outstanding sound quality is CT-aacPlus, a third-generation audio encoding technology. CT-aacPlus is the combination of Advanced Audio Coding (AAC), a highly efficient global standard combining the work of the world's foremost experts on perceptual audio encoding -- AT&T, Dolby, Fraunhofer, and Sony - with Coding Technologies' revolutionary Spectral Band Replication (SBRTM) technology.

Neural Audio created a customized version of its process for XM, designed to enhance CT-aacPlus results by optimizing temporal and spectral elements prior to encoding, improving soundstage clarity, and increasing intelligibility. The unique combination of CT-aacPlus and Neural Audio algorithms enable XM to deliver a consistent, superior sound experience.

In addition, Neural Audio's "stereo transcoder" algorithm preserves the imaging and spatiality of stereo and surround-sound content that XM broadcasts. So XM customers with matrix-style surround sound equipment, including Dolby technology, can receive a full surround sound experience.

well i am asking myself now: why i havent found the website earlier :-/

no aac v2, no full cd-quality!
any further questions?

TomMix 3daywarning on March 12th, 2007 / post 17032

almost three days past now and no response so far. i hope nothing serious happend to spasv :unsure:

SoCoJosh in the SHAdOwZ on March 12th, 2007 / post 17033

TomMix wrote:
:-|

almost three days past now and no response so far. i hope nothing serious happend to spasv :unsure:

bocaccio11 Open your eyes on March 12th, 2007 / post 17070

He's probably tired of the arguments :yes:

TomMix 3daywarning on March 12th, 2007 / post 17072

bocaccio11 wrote:
He's probably tired of the arguments :yes:

i hope not.
but im a bit concerned about him because of the statements he makes:

SpasV wrote:
:-)

m4a @192kbps is much better than mp3 @192 kbps
The sound spectrum bandwidth is 20 Hz - 20,000 Hz, while
mp3's is 20 Hz - 15,000 Hz : This is an essential difference.

it is a contradiction against his own screenshots from above where one can see 192kbit/s mp3
up to 18khz ...
and an hec aac v1 xm stream at 64 - 96kbit/s makes up to 20khz and higher
please follow my links to SBR to learn about how aac artificially constructs this hig-band data

SpasV V.I.P. on March 12th, 2007 / post 17074

Hi,
I am a little bit busy and I need to take a couple of spectra.
For now,
there are mp3 files @192 kbps at 15 kHz bandwidth that you can download here. To me, they are obviously recorded from a FM radio stream.
One can compress a CD rip @192kbps mp3 preserving a 16 kHz bandwidth using a Lame 3.97 encoder.
One can compress a CD rip @192kbps mp3 preserving around 18 kHz bandwidth using a better encoder.
The m4a encoder I use preserves 20 kHz bandwidth.
Finally, the reference “The sound spectrum bandwidth is 20 Hz - 20,000 Hz, while mp3's is 20 Hz - 15,000 Hz : This is an essential difference.” is taken out of the context of a comparison with FM recorded files.
Obviously I have to be more precise but I’ll do this later.

Skype:spas.velev

TomMix 3daywarning on March 12th, 2007 / post 17077

ur very right and i agree, FM radio is limited to 15khz by default.
but where the heck are FM rips on here :unsure:

KISS FM is just the name of the station but it is no FM rip it is a HOTBIRD DAB-S rip :wink:

btw. have you realized that the statement of xm, they dont have cd-like quality, confirms the bitrate of 64 - 96kbit/s hec aac v1 ?!

SpasV V.I.P. on March 13th, 2007 / post 17091

Sorry, I made mistake. If I had to be more precise
I would say "The mp3 @192 kbps sound spectrum bandwidth, I have checked,
was 20 Hz - 16,000 Hz",
not 20 Hz - 15,000 Hz

Skype:spas.velev

SpasV V.I.P. on March 13th, 2007 / post 17092

Here is a little problem as an exercise.
• Download: Jimmie Page and Sander Kleinenberg - at USR on XM80[m4a] - 11-Mar-2007 (if you do not have it)
• Download: Sander Kleinenberg - @ USR on XM80 - 11-Mar-2007 (if you do not have it)
• Run a Spectrum Analysis using Sony Sound Forge 8.0 (there is a month free trail version) on both Sander Kleinenberg’s files
• Comment the results

Skype:spas.velev

SoCoJosh in the SHAdOwZ on March 14th, 2007 / post 17097

when

will this fight END?!?!?! it doesnt MATTER!!!!!!!!!!! only thing most ppl look at on here (users) is how big the file size is... 320 creates a problem for a lot of users... filesize is just too big... quality is one thing.. but cmon.. who cares anymore afer this has gone on for so long.... 192 is the optimal bitrate unless you have sonic ears...

**it... just get over it you guys..... i dont download anything over 192 unless its direct sound files.. like espresso's work with the WMC... stuff like that.. the rest.. pfffffft a waste of bandwidth for me...

:lol:

well u 2 duke it out some more.. just a thought :lol:

SpasV V.I.P. on March 14th, 2007 / post 17101

I agree this is not a discussion.
This has not been a discussion since the very beginning

Skype:spas.velev

TomMix 3daywarning on March 14th, 2007 / post 17105

@SoCoJosh
so i introduced the whole thing :-D

"TomMix" wrote:
i just want bring some light in about how stuff works

and i think we are done.
xm has undoubtable a bitrate of 64 - 96kbit/s of a encrypted hec aac v1 stream
thats all the talk was about. for me at least

@spasv
please, please with sugar on top: dont take any PCM source captured sound to comparsion anymore :no:

u almost got me with ur graphs :wink:

i mean the xm-recorded looked sometimes even bettern than the cd-source :lol:

and by the way: ur uploads encoded with aac lc at 192kbit/s cbr are ... (i wont start another :evil:

)

Ojay mp2/mp3/aac/ogg on March 21st, 2007 / post 17335

TomMix wrote:
and by the way: ur uploads encoded with aac lc at 192kbit/s cbr are ... (i wont start another :evil:

)

But me!

LC-AAC (that means normal AAC without "plus") should now be better than MP3 at the same bitrate (almost as good as Ogg Vorbis) at 192kbps or higher!

Still most people use MP3.