From d86e498088d9fb049d85b24be2fe1327b4cb4163 Mon Sep 17 00:00:00 2001 From: reimar Date: Thu, 19 Feb 2009 13:57:14 +0000 Subject: Try to update libvo.txt git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@28667 b3059339-0415-0410-9bf9-f77b7e298cf2 --- DOCS/tech/libvo.txt | 77 ++++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 64 insertions(+), 13 deletions(-) (limited to 'DOCS') diff --git a/DOCS/tech/libvo.txt b/DOCS/tech/libvo.txt index 70cd3997f0..6176cdbdff 100644 --- a/DOCS/tech/libvo.txt +++ b/DOCS/tech/libvo.txt @@ -6,6 +6,14 @@ Note: before start on this, read colorspaces.txt ! 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. -- cgit v1.2.3