[mythtv-users] Re: Automatic Commercial Detection - how to get it

[Michael T. Dean]

On 09/22/2004 10:36 AM, Gavin Hurlbut wrote:

>Chris Pinkham <cpinkham at bc2va.org> wrote:
>  
>
>>I've yet to look at the audio data enough to know this or not, but I've heard
>>and read that it's not volume, it's something else that changes that makes
>>it seem louder.
>>    
>>
>I think that the commercials are more compressed (using dynamic compression,
>not like MP3 compression), so they appear louder to the human ear.  Also, they
>may also be boosting the levels after the compression.
>  
>
Yeah.  That seems to be the most common cause for the apparent 
difference.  Fortunately, enough consumers have been so upset by the 
apparent increase in volume that a lot of tax-payer dollars around the 
world have been spent to figure out what's going on...

Here are some links:

Best technical description:  
http://www.mastersonaudio.com/audio/20020801.htm
Nice article describing a gadget that "corrects" audio level - gives 
some good things to think about: 
http://www.tvtechnology.com/features/Inside-Audio/f_dm_inside_audio-03-05-03.shtml
Slightly technical, pretty humorous: 
http://www.cosmik.com/aa-march03/karl92.html
 From Canada: http://www.crtc.gc.ca/eng/INFO_SHT/G3.HTM
 From Australia: 
http://www.aba.gov.au/tv/investigations/projects/loud_advertisements/rpt_disc1.htm
 From the US: http://www.fcc.gov/cgb/consumerfacts/backgroundnoise.html

Mike