From owner-freebsd-multimedia Fri Jul 25 18:43:53 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id SAA07808 for multimedia-outgoing; Fri, 25 Jul 1997 18:43:53 -0700 (PDT) Received: from rah.star-gate.com (rah.star-gate.com [204.188.121.18]) by hub.freebsd.org (8.8.5/8.8.5) with ESMTP id SAA07802 for ; Fri, 25 Jul 1997 18:43:51 -0700 (PDT) Received: from rah.star-gate.com (localhost.star-gate.com [127.0.0.1]) by rah.star-gate.com (8.8.5/8.8.5) with ESMTP id SAA00696; Fri, 25 Jul 1997 18:43:46 -0700 (PDT) Message-Id: <199707260143.SAA00696@rah.star-gate.com> X-Mailer: exmh version 2.0gamma 1/27/96 To: lamaster@george.arc.nasa.gov cc: freebsd-multimedia@FreeBSD.ORG In-reply-to: Your message of "Fri, 25 Jul 1997 17:09:00 PDT." <199707260009.RAA15761@george.arc.nasa.gov> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Fri, 25 Jul 1997 18:43:46 -0700 From: Amancio Hasty Sender: owner-freebsd-multimedia@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk >From The Desk Of lamaster@george.arc.nasa.gov : > friendly, so the system can handle it, but MPEG-2 decode will want > most of the CPU, so it would be nice if the X server were better > optimized for painting video images in a window. With respect to the X server and additional functionality needed to support high speed mpeg decoding what we need is: 1. yuv to rgb in hardware . matrox and s3 cards support such functionality 2. scaling with antialising. matrox and s3 cards support such functionality 4. Direct Memory access is already provided by DGA and is proving to be useful for cool video apps such as fxtv . 3. For Pentium Pros and Pentium II enable write combining for the frame buffer. This can boost the memory bandwith to the frame buffer by a factor or 5 so . Typically, when write combining is not enabled the thruput to a PCI frame buffer is around 20MBs or so when when write combining is enable the thruput for a decent video adapter jumps to 80MB/sec to 90MB/sec. You can easily test this assumption by dowloading the DOS utility fastvid. I managed to write something similar so if anyone is interested just e-mail me. On Win95 and WinNT the above functionality is readily available at least the first two via directdraw so we should come up with a cool api to do the same thing 8) Also anyone with a databook for a modern graphic adapter should be able to code up a simple api . That, Thats, All Folks 8) Amancio