[MPlayer-cvslog] r28667 - trunk/DOCS/tech/libvo.txt
reimar
subversion at mplayerhq.hu
Thu Feb 19 14:57:15 CET 2009
Author: reimar
Date: Thu Feb 19 14:57:14 2009
New Revision: 28667
Log:
Try to update libvo.txt
Modified:
trunk/DOCS/tech/libvo.txt
Modified: trunk/DOCS/tech/libvo.txt
==============================================================================
--- trunk/DOCS/tech/libvo.txt Thu Feb 19 13:19:55 2009 (r28666)
+++ trunk/DOCS/tech/libvo.txt Thu Feb 19 14:57:14 2009 (r28667)
@@ -6,6 +6,14 @@ Note: before start on this, read colorsp
The constants for different pixelformats are defined in img_format.h,
their usage is mandatory.
+WARNING: Please keep in mind that some of this information may be out-dated,
+so if you are working on a new vo, consider submitting preliminary patches
+very early on. Currently vo_gl is one of the more up-to-date VOs to use
+as reference if you are unsure about something and do not want to ask on the
+list.
+vo_vdpau and vo_direct3d may be a good choice, too, they use different
+approaches closer to the sometimes convoluted way DirectX works.
+
Each vo driver _has_ to implement these:
preinit():
@@ -15,7 +23,9 @@ Each vo driver _has_ to implement these:
Uninit the whole system, this is on the same "level" as preinit.
control():
- Current controls:
+ Current controls (VOCTRL_QUERY_FORMAT must be implemented,
+ VOCTRL_DRAW_IMAGE, VOCTRL_FULLSCREEN, VOCTRL_UPDATE_SCREENINFO
+ should be implemented):
VOCTRL_QUERY_FORMAT - queries if a given pixelformat is supported.
It also returns various flags decsirbing the capabilities
of the driver with teh given mode. for the flags, see
@@ -64,7 +74,37 @@ Each vo driver _has_ to implement these:
by drivers which use X11, except SDL, as well as directx and
gl2 under Windows.
VOCTRL_BORDER
- Makes the player window borderless. Only supported by directx.
+ Makes the player window borderless.
+ VOCTRL_FULLSCREEN
+ Switch from and to fullscreen mode
+ VOCTRL_GET_PANSCAN
+ VOCTRL_SET_PANSCAN
+ Needed to implement pan-scan support ('w' and 'e' keys during
+ playback in fullscreen mode)
+ VOCTRL_START_SLICE
+ Called before the first draw_slice of each frame, useful if
+ you need to do some set-up work.
+ VOCTRL_DRAW_EOSD
+ Required for EOSD (ASS subtitle) support. Provides all
+ information necessary to draw the EOSD for the current video
+ frame.
+ VOCTRL_GET_EOSD_RES
+ Required for EOSD (ASS subtitle) support. Informs the ASS
+ renderer about the properties of the drawing area (size,
+ borders).
+ VOCTRL_SET_DEINTERLACE
+ VOCTRL_GET_DEINTERLACE
+ Get or set deinterlacing status for VOs that support some kind
+ of deinterlacing.
+ VOCTRL_UPDATE_SCREENINFO
+ Should set the xinerama_x, xinerama_y, vo_screenwidth and
+ vo_screenheight appropriately for the currently used
+ monitor and -xineramascreen option.
+ Usually should simply call the w32_update_xinerama_info or
+ update_xinerama_info function.
+ By supporting this, the VO also requests the newer API
+ that sets vo_dx, vo_dy etc. appropriately before config()
+ is called.
config():
Set up the video system. You get the dimensions and flags.
@@ -86,25 +126,22 @@ Each vo driver _has_ to implement these:
So, you can check for vo_config_count>0 in uninit() when freeing
resources allocated in config() to avoid crash!
- You should call geometry() in config() to enable user defined
- window size and position. The code should look as following:
- ---
- set x,y,w,h to the values supplied by the caller or to those you deam
- useful.
- call geometry(&x, &y, &w, &h, screenw, screenh)
- call aspect()
- ---
- see libvo/geometry.c for further information
+ You should implement VOCTRL_UPDATE_SCREENINFO so that vo_dx, vo_dy,
+ vo_dwidth and vo_dheight are already pre-set to values that take
+ aspect and -geometry into account. It is also necessary to properly
+ support multi-monitor setups (if based on x11_common, w32_common).
draw_slice(): this displays YV12 pictures (3 planes, one full sized that
contains brightness (Y), and 2 quarter-sized which the colour-info
(U,V). MPEG codecs (libmpeg2, opendivx) use this. This doesn't have
to display the whole frame, only update small parts of it.
+ If this is not supported, it must be signaled in QUERY_FORMAT with
+ VOCAP_NOSLICES.
draw_frame(): this is the older interface, this displays only complete
frames, and can do only packed format (YUY2, RGB/BGR).
Win32 codecs use this (DivX, Indeo, etc).
- If you implement VOCTRL_DRAW_IMAGE, you can left draw_frame.
+ If you implement VOCTRL_DRAW_IMAGE, you do not need to implement draw_frame.
draw_osd(): this displays subtitles and OSD.
It's a bit tricky to use it, since it's a callback-style stuff.
@@ -113,11 +150,25 @@ Each vo driver _has_ to implement these:
The vo_draw_text() checks the characters to draw, and calls
draw_alpha() for each. As a help, osd.c contains draw_alpha for
each pixelformats, use this if possible!
+ Note that if you do not draw directly onto the video you should
+ use vo_draw_text_ext() which allows you to specify the border
+ values etc. needed to draw DVD menu highlights at the correct place.
+ If you do not want to implement this, you can still use -vf
+ expand=osd=1 to draw the OSD, or even implement code to insert
+ this filter automatically.
+ Make sure you set VFCAP_OSD depending on whether you implemented it
+ or not.
NOTE: This one will be obsolete soon! But it's still useful when
you want to do tricks, like rendering osd _after_ hardware scaling
(tdfxfb) or render subtitles under of the image (vo_mpegpes, sdl)
- flip_page(): this is called after each frame, this diplays the buffer for
+ NOTE2: above NOTE is probably wrong, there are currently no plans to
+ obsolete draw_osd, though there is the more advanced EOSD support for
+ ASS subtitles.
+
+ flip_page(): this is called after each frame, this displays the buffer for
real. This is 'swapbuffers' when doublebuffering.
+ Try to do as little work here as possible, since that affect jitter/
+ A-V sync.
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