[vorbis] Video codec

[Chrissy and Raul]

Hi, it is great to be back.

Let me answer inline below:

>From: Ralph Giles <giles at snow.ashlu.bc.ca>
>Reply-To: vorbis at xiph.org
>To: vorbis at xiph.org
>Subject: Re: [vorbis] Video codec
>Date: Sun, 10 Sep 2000 11:57:25 -0700 (PDT)
>
>On Fri, 8 Sep 2000, Sean Wieland wrote:
>
> > Well, I was thinking more along the lines of reasonable storage
> > considerations.  At least 5GB per DVD is a bit harsh.  Whereas .5GB per
> > OGG-Video means plenty of room on one of those new 80GB hard drives for
> > a good-sized movie collection in addition to a good-sized CD collection,
> > all of the regular apps, games, etc.
>
>Alright, I see what you mean. I just wanted to be clear that DVD-video is
>already lossily compressed; what you were asking for was not "Oh look, I
>can fit my CD collection in 1/10th the space using Vorbis" but "Oh look, I
>can fit my mp3 collection in 1/10th the space using Vorbis *and*
>downsampling to 11kHz mono".
>
> > I'm talking about 352x240 resolution VHS-quality streaming video at
> > about 100kbps.
> > I agree that DVD level resolution and quality without broadband would be
> > extremely difficult (as in near impossible).  Although DVD resolution
> > and quality at about 1Mbps for archive on CD would be nice.
>
>I still think this is overly optimistic. None of the current codecs come
>close to VHS quality at 100kbps. But we'll see. ;-)

Lets go step by step downwards in bitrate.

I agree that for Internet media streaming, we have to concentrate on SIF 
(quarter-screen) resolution.  My reason is that DSL and other broadband 
connections will be around 384 Kbps for a while.  For wireless devices 3G is 
going to start at 348 Kbps.

If you look at how formats like Windows Media, RealVideo and QuickTime split 
audio and video, the audio part becomes more and more important 
percentagewise as you increase compression.  At 512 Kbps, RealVideo 
allocates 96 Kbps to audio in most cases, at 384 Kbps, 64 Kbps is more 
common for audio.  WindowsMedia and QuickTime can be easily setup for those 
and other mixes.  You can check:

http://www.izahi.com/internet_media

for examples of two Audio/Video clips encoded at 384 and 512 Kbps using 
several free encoders.  Please also notice the "free-ness" of this 
comparison, encoders that cost something can improve quality as 
QuickTime/Sorenson claim in their websites.  Notice also with whatever 
connection that you have how long the clip takes to start, if it plays 
smoothly (or with internet delays/clogging/etc), if it downloads or streams. 
  All of the clips are files on a server with NO special serving software, 
the client decides how to play the clip.  Of course, please look at the 
quality.

RealVideo and Windows Media start dropping frames below 384 Kbps for 
high-motion video like sports.

Complete media (audio/video) delivery at 384 Kbps, SIF (320x240, since we 
"already agreed" on square pixels) resolution and 30 frames per second(fps), 
is possible today with average-to-low picture quality for most video that we 
want to see (I suggest channel surfing on TV during a typical viewing day to 
check action vs. talking heads vs. soft pictures vs. news).

One very important step in the video codec definition is what resolution, 
frame rate and bitrates are acceptable/practical.

For now, I have not seen evidence of 128 Kbps media delivery at SIF 
resolution and I think QSIF (160x120) resolution is only good for video 
phones or media including one single talking head.

RAUL LOPEZ

>
>  -r
>
>
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