[MPlayer-dev-eng] [PATCH] dvdnav part 3 - emptyframe

[Reimar Doeffinger]

Hello,
On Tue, Jul 31, 2007 at 04:13:05PM +0200, Michael Niedermayer wrote:
> btw, vo_gl.c get_image does
> 
>  if (mpi->flags & MP_IMGFLAG_READABLE) return VO_FALSE;
>  if (mpi->type == MP_IMGTYPE_IP || mpi->type == MP_IMGTYPE_IPB)
>     return VO_FALSE; // we can not provide readable buffers
> 
> isnt the 2nd if wrong? i mean if MP_IMGFLAG_READABLE isnt set then the
> decoder shouldnt read from the buffer
> (note writes could cause cache lines to be fetched if things arent
> configured correctly ...)

In theory yes, in practice MPlayer just forgets to set the readable flag
even when it is needed, resulting in now really horrible speed when this
is removed (at least that were my test results when I wrote the code).

> also if draw_slice (many glUploadTex) is so slow while a single glUploadTex
> is fast then maybe allocating a buffer get_image() style and then
> memcpy_agp / memcpy into that for each slice might be faster ...

Yes, possibly. But I fear that actually the situation might be
completely reversed for AGP vs. PCIe, at least I can't remember this
issue appearing on my old systems.
But since I as said did not do any proper measurements since it is only
guesswork.

Greetings,
Reimar Doeffinger