Talk:GenReS

To be really useful for the vidoesecurity applications plugin needs to implement pan (without decoding all the throuwn-away data), not just zoom as we discussed a year ago :-). At least with a step of one macroblock (16x16 pixels with no decimation), and even with JPED DC coefficients are not independent (difference in scan-line order is encoded).

Of course that will require getting inside the Mplayer to add the additionbal processing, but that is really needed for the multiple cameras applications.

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lowres parameter is passed to mplayer as -lavdopts lowres=<value>. From man mplayer:

lowres=<number>[,<w>]
                     Decode  at  lower  resolutions.  Low resolution decoding is not supported by all codecs, and it will
                     often result in ugly artifacts.  This is not a bug, but a side effect of not decoding at full  reso-
                     lution.
                        0: disabled
                        1: 1/2 resolution
                        2: 1/4 resolution
                        3: 1/8 resolution

I look that with mjpeg it works fine. Decoding with 1/8 resolution needs 1/2 of full decoding time. But 1/16 is not implemented in mplayer. --Sergey Khlutchin 12:34, 20 November 2005 (CST)

Yes, I understand that Mplayer does not have windowing feature that would allow faster decoding just a selected window from the full frame that is streamed. That will require to get into Mplayer itself - both pass the additional parameters for the window selection and actually implement windoiw processing. But I don't think it is too difficult and we definitely need it.

Other parameter that we need to pass to plugin - drop specified number of frames (reduce on-screen frame rate) - show each N-th frame. This too will help us to have more active camera preview windows on the same computer. --Andrey.filippov 20:47, 20 November 2005 (CST)