[geeks] Whee! Lightning strikes, AGAIN!

[Joshua Boyd]

On Wed, Jul 29, 2009 at 07:17:40PM +0300, gsm at mendelson.com wrote:

>> That said, a really smart encode is still limited by how stupid many
>> decoders are, and as such, a fixed pattern of I frames (key frames) and
>> non I frames is often required (called a group of pictures, GOP).
>
> I don't know how true that is. Most of the Chinese DVD players run some
> sort of Linux with an mplayer/vlc/xine derived playing engine. AFAIK they
> all have a mechanism in place to load a new set of firmware into flash,
> although details of the exact mechanism and how to package your own version 
> are obscure. 

It is hard to believe that of the chinese dvd players I've seen
recently.  Wouldn't a completely integrated chip be cheaper?

Also, it could be possible that the dvd player does run linux
and mplayer, but actual decoding it handed off to a MPEG2 decoder chip
that is limited in how much variation away from certain standards it can
support. 

> So far no one seems to have bothered to produce the equivalent of DD-WRT
> or Tomato, etc (Linksys WRT54G-L router) Linux distributions for custom 
> loading, nor have customization toolkits appeared for them.

That would be interesting to see.

>> AAC was actually introduced in MPEG2 Part 7.
>
> Ok, wouldn't that make it too late for the MPEG2 used in DVD's or was it
> considered just too complicated for the time?

I don't know which, but I would presume it was too late for DVDs.

>> Both MPEG2 and MPEG4 have been extended to carry numerous audio types
>> other than just MP3 or AAC.  Also extensively used are AC3, AC3+, DTS,
>> and Dolby E.
>
> As long as a DVD has a "regular" audio track too, then the disk would
> be compatible with older players, assuming anyone has them. Mine last 3-6 
> months, depending upon the abuse my kids give them and how rarely they
> get the dust blown off.

I've never seen a DVD player without both AC3 and DTS support, but that
isn't to say it couldn't exist.  I didn't get into the DVDs until 2000
though. 

> Our living room DVD player is a computer running Mythtv, which used to go
> through DVD drives every 6 months until I started putting the heavily used
> stuff as MP4 files on the hard drive. Before anyone goes and says anything,
> I'm not in the US, it's legal here.

I'm thinking of doing a myth box to replace our DVD player.