[vorbis] Video codec

[Chrissy and Raul]

Hi,

I guess this is a good time to start putting together a wish list for a 
video codec.

I see that for audio the compression is around 10X for reasonable quality.  
I am sure this will start its own thread of conversation.

For video you can do 40X fairly easily and the big task is to go to 80X or 
100X with reasonable picture quality, say, a peak luma SNR of more than 30 
dB.  Uncompressed Professional Quality video (called "D1" see below), like 
the one at TV stations before broadcast, is 216 Mbps.  Smaller resolutions 
have less bps of course.

One of the many tasks is going to be to work around the existing patents but 
if the audio guys can do it, the video guys should be able to as well.  Not 
everything has been discovered or patented for video compression.

I suggest to focus on "SIF", quarter-screen video (352x240 for NSTC 
rectangular, TV, pixels and 320x240 for square, computer, pixels).  For 
nomenclature purposes full screen is "VGA" is 640x480p progressive and "D1" 
is 720x480i interlaced (some people also use "Half D1" 360x480i for some 
products).  Computers are progressive, TV is interlaced.  30 Frames/second, 
or 60 fields/second yields a natural moving image that does not suffer too 
much from "jumpiness" during pans.  Movie film is 24 fps sometimes 
presenting each frame three times for a net 72 fps.

Experiments show good quality for SIF, 30 progressive frames/second at 512 
Kbps system bitrate (Audio is 96 Kbps).  There are some experiments on D1 
(full) resolution at 1.5 Mbps video-only but the quality is not good.  D1 
resolution at 3 Mbps can look good today.

Any input on desired resolutions, bitrates, color resolution (color 
subsampling), frame rates, etc?

I will be unavailable until Monday, Sep 11th so if you send e-mail or post 
questions I will not be able to get back to you until Sep 11th.

Excuse the apparent lack of order, I just want to start throwing 
ideas/concepts to the list.  All can be clarified and classified in due 
time.

RAUL LOPEZ
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