PS3 Trailer's AAC vs PCM/DD-HD/DTS-MA/etc.?

[Blu3]

Hi,

I've always wondered how the PS3 downloaded trailers from the PS Store, who use AAC for audio, IIRC 2 channel at a low kilo bit rate, have so much sound and high volume compared to the usual codecs used in full features. Why not just use AAC for the full features? Or is it just not as good as the usual DD-HD, DTS-MA, PCM, etc.?

I'm a noob with little time to search, so please if this has been asked or covered a 1000 times before, sorry and I'll take the short answer

TIA

[fronn]

Originally Posted by Blu3

Hi,

I've always wondered how the PS3 downloaded trailers from the PS Store, who use AAC for audio, IIRC 2 channel at a low kilo bit rate, have so much sound and high volume compared to the usual codecs used in full features. Why not just use AAC for the full features? Or is it just not as good as the usual DD-HD, DTS-MA, PCM, etc.?

I'm a noob with little time to search, so please if this has been asked or covered a 1000 times before, sorry and I'll take the short answer

TIA

Actually, this is exactly what's wrong with much of audio today. Volume doesn't equal quality, often it's quite the opposite -- the ipod generation is ruining our audio But that is another story/rant.

The AAC audio on those trailers is going to be missing a lot of the sound information -- it may get just as loud (although that's sort of independent of the codec used), but it's going to lack subtleties and proper frequency ranges. AAC isn't terrible, but it's ultimately still compressed quite a bit -- if you know what to listen for it's rather easy to hear the side effects of audio compression. That's not to say there aren't excellent compressed audio tracks out there that are quite hard to tell that they are compressed (Transformers HD DVD and Kingdom of heaven BR both have spectacular 1.5mb compressed tracks, for example).

To make a long story short, AAC is just the standard audio Sony picked (as it's the audio format they like over MP3). They probably don't want to pay for Dolby/DTS licensing for a minute long trailer, and they've never been a fan of MP3 (AAC is said to be a little better than MP3, at least). AAC isn't meant for multiple channel audio, so it wouldn't be practical to use on an actual movie -- it also lacks the advanced features that DTSHDMA or Dolby TrueHD have.

[Blu3]

Originally Posted by fronn

Actually, this is exactly what's wrong with much of audio today. Volume doesn't equal quality, often it's quite the opposite -- the ipod generation is ruining our audio But that is another story/rant.

The AAC audio on those trailers is going to be missing a lot of the sound information -- it may get just as loud (although that's sort of independent of the codec used), but it's going to lack subtleties and proper frequency ranges. AAC isn't terrible, but it's ultimately still compressed quite a bit -- if you know what to listen for it's rather easy to hear the side effects of audio compression. That's not to say there aren't excellent compressed audio tracks out there that are quite hard to tell that they are compressed (Transformers HD DVD and Kingdom of heaven BR both have spectacular 1.5mb compressed tracks, for example).

To make a long story short, AAC is just the standard audio Sony picked (as it's the audio format they like over MP3). They probably don't want to pay for Dolby/DTS licensing for a minute long trailer, and they've never been a fan of MP3 (AAC is said to be a little better than MP3, at least). AAC isn't meant for multiple channel audio, so it wouldn't be practical to use on an actual movie -- it also lacks the advanced features that DTSHDMA or Dolby TrueHD have.

Fantastic - thanks. That was my guess too. I just found it funny that I had to turn the volume down every time I played a trailer vs a movie.

And yeah, I'll take CD quality audio over MP3 any day of the week.