[BC] Does a Glut of New Signals Mean More Revenue?

[Goran Tomas]

--- At 27.8.2006 01:48, Dana  Puopolo wrote: ---
>I meant MPEG-2 as in MP4 or AAC.
>
>OR as in here:
>
>http://en.wikipedia.org/wiki/MPEG-2


AAC is indeed included in both MPEG-2 and MPEG-4 standards but it is 
generally referred to as being MPEG-4. That is to say it is most 
often used inside the MPEG-4 container, hence the labels and 
extensions MP4 or M4A.

MPEG standards actually include various audio and video codecs, so 
using a standard's name can mean various things. For example MPEG-4 
can use MPEG Layer-II (MP2), MPEG Layer-III (MP3), AAC (main), AAC-LD 
(low delay), AAC-LTP (long term prediction), AAC-LC (low complexity), 
AAC-HE (high efficiency, aka aacPlus), AAC-HE v2 (aacPlus v2), CELP, etc...

Now, if your stream is 57kbps AAC mono, than indeed there should be 
no reason why IBOC at 48 kbps would sound better - apart from being 
mono :-( IMO, it would actually sound better (meaning there would be 
less noticeable artifacts) which is understandable as it encodes only 
one channel and it also uses higher bitrate to do so:

ftp://161.53.122.20/Streaming_Codecs_comparison/48kbps_AAC-HE_vs_56kbps_AAC-LC/Grease_AAC_HE_48kbps_stereo.aac
ftp://161.53.122.20/Streaming_Codecs_comparison/48kbps_AAC-HE_vs_56kbps_AAC-LC/Grease_AAC_LC_56kbps_mono.mp4

However on some program material, stereo audio (albeit with a bit 
more artifacts) would probably sound better to most people:

ftp://161.53.122.20/Streaming_Codecs_comparison/48kbps_AAC-HE_vs_56kbps_AAC-LC/ABC_AAC_HE_48kbps_stereo.aac
ftp://161.53.122.20/Streaming_Codecs_comparison/48kbps_AAC-HE_vs_56kbps_AAC-LC/ABC_AAC_LC_56kbps_mono.mp4

(To actually hear the difference you should download the files and 
play them with WinAmp v5.05 or higher. OR with Windows Media Player 
with Orban plug-in http://www.orban.com/plugin )

But, I'm afraid the comments you get have to do more with the 
marketing of "HD quality" and "HD radio" and "digital quality" rather 
than what people really hear or don't hear. It's like listening to an 
"subjective audiophile" describing to you with conviction how his new 
interconnects drastically improved the imaging, depth and transient 
response of his audio system. And I'm sure he actually hears it in his mind...


Regards,
Goran Tomas