[theora-dev] resolution issues

Mauricio Piacentini mauricio at tabuleiro.com
Tue Jun 3 13:49:59 PDT 2003

I have just implemented this change and it is checked into the CVS tree.
Update your local copies, and remember that this is a bitstream change, so
content needs to be reencoded.
The encoder_example has been revised to do the right thing. The players are
however still displaying the whole decoded frame window. I guess this is
useful for debugging at this time, allowing developers to check if the
offset is correct, etc. It should be trivial to instruct the player to only
get the pixels in the specified rectangle, maybe with a flag.


> after discussion on IRC, it was provisionally agreed (by those present at
the time) that Theora should support arbitrary pixel sizes (presently it is
limited to multiples of 16 both horizontally and vertically).
> It is felt that this can be achieved with minimal pain by adding four
values to the page header, immediately following the present width & height
parameters (before fps_numerator & fps_denominator): pixel_width,
pixel_height, x_offset, and y_offset (or somesuch).
> The existing width & height parameters specify (in 16x16 units as they do
now) the encoded frame size, which will always be a multiple of 16x16
blocks. The new parameters should specify a rectangle within said encoded
frame which correspond to the actual pixels to be displayed. The encoder is
responsible for properly promoting the incoming image to a multiple of
16x16, and specifying the cropping rectangle (-dbm 5/22/03)

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