Bug 10438

Summary: i965 Xv scaling wrong for nonsquare pixels
Product: xorg Reporter: Doug Larrick <doug>
Component: Driver/intelAssignee: Eric Anholt <eric>
Status: RESOLVED FIXED QA Contact: Xorg Project Team <xorg-team>
Severity: normal    
Priority: medium    
Version: git   
Hardware: x86 (IA32)   
OS: Linux (All)   
URL: http://www.parkercat.org/doug/i965_video.patch
Whiteboard:
i915 platform: i915 features:
Bug Depends on:    
Bug Blocks: 10102    
Attachments:
Description Flags
Patch for i965_video.c none

Description Doug Larrick 2007-03-27 17:35:28 UTC 
MythTV implements "bob" deinterlacing by rearranging the scanlines of an
interlaced picture such that the first field's lines are in the top half
of the picture, and the second field's lines are in the bottom half.  It
then does XvShmPutImage with first the top half of the frame (one field)
then the bottom, at twice the video's interlaced frame rate.  It is
counting on the video card/driver to scale the output back to full
height.  I wrote this code.  It has worked for a few years for many
people on a variety of hardware.  

Example debug output from i830_video.c, I830PutImage :

  I830PutImage: src: (0,0)(704,240), dst: (209,50)(960,720)
  width 704, height 480
  I830PutImage: src: (0,240)(704,240), dst: (209,51)(960,720)
  width 704, height 480

With the current Intel driver (as well as with recent i810 drivers), the video is not scaled to fit the entire window, instead showing in the top half only.

The simple patch in the supplied URL fixes this problem for me.
Comment 1 Doug Larrick 2007-03-27 17:37:02 UTC 
Created attachment 9332 [details] [review]
Patch for i965_video.c
Comment 2 Doug Larrick 2007-03-28 14:29:09 UTC 
You can see a related effect in the GXine or Totem movie players by zooming in on a video while it's playing.  The video takes up progressively less of the window with each zoom step.  With the patch, it works properly.
Comment 3 Eric Anholt 2007-04-17 10:50:51 UTC 
Fixed with a slightly different patch.  Thanks!

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