2.3.1. Video output devices

General:

  x11  X11 with optional SHM extension
xvX11 using overlays with the Xvideo extension (hardware YUV & scaling)
OpenGL renderer, so far works only with:
  • all cards with Utah-GLX
  • Matrox cards with X/DRI >=4.0.3
  • Radeon with X/DRI CVS
dgaX11 DGA extension
fbdevOutput to general framebuffers
svgaOutput to SVGAlib
sdl   1.1.7: supports software scaling
  1.1.8: supports Xvideo (hardware scaling/fullscreen)
  1.2.0: supports AAlib (-vo aa is very recommended, see below!)
ggisimilar to SDL
aatextmode rendering with AAlib
vesaOutput to VESA BIOS.

Card specific:

  mga  Matrox G200/G400 hardware YUV overlay via the mga_vid device
xmgaMatrox G200/G400 overlay (mga_vid) in X11 window
(Xv emulation on X 3.3.x!)
syncfbMatrox G400 YUV support on framebuffer (obsoleted, use mga/xmga)
3dfxVoodoo3/Banshee hardware YUV (/dev/3dfx) support (not yet tested, maybe broken)
tdfxfbVoodoo3/Banshee hardware YUV support on tdfx framebuffer (works!)

Special:

  png  PNG files output (use -z switch to set compression)
pgmPGM files output (for testing purposes or ffmpeg encoding)
md5MD5sum output (for MPEG conformance tests)
nullNull output (for speed tests/benchmarking)

NOTE: check the following subsections for details and requirements!

2.3.1.1. Setting up MTRR

It is VERY recommended to check if the MTRR registers are set up properly, because they can give a big performance boost.

Do a 'cat /proc/mtrr' :

--($:~)-- cat /proc/mtrr
reg00: base=0xe4000000 (3648MB), size= 16MB: write-combining, count=9
reg01: base=0xd8000000 (3456MB), size= 128MB: write-combining, count=1

It's right, shows my Matrox G400 with 16Mb memory. I did this from XFree 4.x.x , which sets up MTRR registers automatically.

If nothing worked, you have to do it manually. First, you have to find the base address. You have 3 ways to find it:

Then let's find the memory size. This is very easy, just convert video ram size to hexadecimal, or use this table:

  1 MB0x100000
2 MB0x200000
4 MB0x400000
8 MB0x800000
16 MB0x1000000
32 MB0x2000000

You know base address and memory size, let's setup mtrr registers! For example, for the Matrox card above (base=0xd8000000) with 32MB ram (size=0x2000000) just execute:

  echo "base=0xd8000000 size=0x2000000 type=write-combining" >| /proc/mtrr

Not all CPUs support MTRRs. For example older K6-2's [around 266Mhz, stepping 0] doesn't support MTRR, but stepping 12's do ('cat /proc/cpuinfo' to check it').

2.3.1.2. Xv

Under XFree86 4.0.2 or newer, you can use your card's hardware YUV routines using the XVideo extension. This is what the option '-vo xv' uses. In order to make this work, be sure to check the following:

2.3.1.2.1. 3dfx cards

Older 3dfx drivers were known to have problems with XVideo acceleration, it didn't support either YUY2 or YV12, and so. Verify that you have XFree86 version 4.1.0 or greater, it works ok. Alternatively, you can use DRI cvs. If you experience strange effects using -vo xv, try SDL (it has XVideo too) and see if it helps. Check the SDL section for details.

OR, try the NEW -vo tdfxfb driver! See the 2.3.1.9 section!

2.3.1.2.2. S3 cards

S3 Savage3D's should work fine, but for Savage4, use XFree86 version 4.0.3 or greater (in case of image problems, try 16bpp). As for S3 Virge.. sell it.

NOTE: Savage4 has a slow YV12 image displaying capability (it needs to do YV12->YUY2 conversion, because the Savage hardware can't display YV12). So when this documentation says at some point "this has YV12 output use this, it's faster", you shouldn't. Stick to YUY2.

2.3.1.2.3. nVidia cards

nVidia isn't a very good choice under Linux.. You'll have to use the binary nVidia driver, available at nVidia's website. The standard X driver doesn't support XVideo for these cards, due to nVidia's closed sources/specifications.

2.3.1.2.4. ATI cards

  • The GATOS driver (which you should use) has VSYNC enabled by default. It means that decoding speed (!) is synced to the monitor's refresh rate. If playing seems to be slow, try disabling VSYNC somehow, or set refresh rate to n*(fps of the movie) Hz.
  • Radeon VE - currently only XFree86 CVS has driver for this card, version 4.1.0 doesn't. Of course with MPlayer you can happily get accelerated display, with or without TV output, and no libraries or X are needed. Read VESA driver and Radeon acceleration sections).
  • 2.3.1.2.5. NeoMagic cards

    These cards can be found in many laptops. Under Linux, their peak is only DGA. Unfortunately, the DGA driver in X 4.1.0 doesn't work, you'll have to wait for 4.2.0, or download a modified driver for 4.0.3 or 4.1.0 from here : http://www.mplayerhq.hu/MPlayer/contrib/NeoMagic-driver (there is also the patch to the driver's source).
    Drivers provided by Tomek Jarzynka.

    2.3.1.3. DGA

    2.3.1.3.1. Summary

    This document tries to explain in some words what DGA is in general and what the DGA video output driver for mplayer can do (and what it can't).

    2.3.1.3.2. What is DGA

    DGA is short for Direct Graphics Access and is a means for a program to bypass the X-Server and directly modifying the framebuffer memory. Technically spoken this happens by mapping the framebuffer memory into the memory range of your process. This is allowed by the kernel only if you have superuser privileges. You can get these either by logging in as root or by setting the suid bit on the mplayer excecutable (NOT recommended!).

    There are two versions of DGA: DGA1 is used by XFree 3.x.x and DGA2 was introduced with XFree 4.0.1.

    DGA1 provides only direct framebuffer access as described above. For switching the resolution of the video signal you have to rely on the XVidMode extension.

    DGA2 incorporates the features of XVidMode extension and also allows switching the depth of the display. So you may, although basically running a 32 bit depth XServer, switch to a depth of 15 bits and vice versa.

    However DGA has some drawbacks. It seems it is somewhat dependent on the graphics chip you use and on the implementation of the XServer's video driver that controls this chip. So it does not work on every system ...

    2.3.1.3.3. Installing DGA support for MPlayer

    First make sure X loads the DGA extension, see in /var/log/XFree86.0.log:

        (II) Loading extension XFree86-DGA

    See, XFree86 4.0.x or greater is VERY RECOMMENDED! MPlayer's DGA driver is autodetected on ./configure, or you can force it with --enable-dga.

    If the driver couldn't switch to a smaller resolution, experiment with switches -vm (only with X 3.3.x), -fs, -bpp, -zoom to find a video mode that the movie fits in. There is no converter right now.. :(

    Become ROOT. DGA needs root access to be able to write directly video memory. If you want to run it as user, then install MPlayer SUID root:

        chown root /usr/local/bin/mplayer
        chmod 750 /usr/local/bin/mplayer
        chmod +s /usr/local/bin/mplayer

    Now it works as a simple user, too.

    !!!! BUT STAY TUNED !!!!
    This is a BIG security risk! Never do this on a server or on a computer can be accessed by more people than only you because they can gain root privilegies through suid root mplayer.
    !!!! SO YOU HAVE BEEN WARNED ... !!!!

    Now use '-vo dga' option, and there you go! (hope so:) You should also try if the '-vo sdl:dga' option works for you! It's much faster!!!

    2.3.1.3.4. Resolution switching

    The DGA driver allows for switching the resolution of the output signal. This avoids the need for doing (slow) software scaling and at the same time provides a fullscreen image. Ideally it would switch to the exact resolution (except for honouring aspect ratio) of the video data, but the XServer only allows switching to resolutions predefined in /etc/X11/XF86Config (/etc/X11/XF86Config-4 for XFree 4.0.X respectively). Those are defined by so-called modelines and depend on the capabilites of your video hardware. The XServer scans this config file on startup and disables the modelines not suitable for your hardware. You can find out which modes survive with the X11 log file. It can be found at: /var/log/XFree86.0.log.

    See appendix A for some sample modeline definitions.

    2.3.1.3.5. DGA & MPlayer

    DGA is used in two places with MPlayer: The SDL driver can be made to make use of it (-vo sdl:dga) and within the DGA driver (-vo dga). The above said is true for both; in the following sections I'll explain how the DGA driver for MPlayer works.

    2.3.1.3.6. Features of the DGA driver

    The DGA driver is invoked by specifying -vo dga at the command line. The default behaviour is to switch to a resolution matching the original resolution of the video as close as possible. It deliberately ignores the -vm and -fs switches (enabling of video mode switching and fullscreen) - it always tries to cover as much area of your screen as possible by switching the video mode, thus refraining to use a single additional cycle of your CPU to scale the image. If you don't like the mode it chooses you may force it to choose the mode matching closest the resolution you specify by -x and -y. By providing the -v option, the DGA driver will print, among a lot of other things, a list of all resolutions supported by your current XF86-Config file. Having DGA2 you may also force it to use a certain depth by using the -bpp option. Valid depths are 15, 16, 24 and 32. It depends on your hardware whether these depths are natively supported or if a (possibly slow) conversion has to be done.

    If you should be lucky enough to have enough offscreen memory left to put a whole image there, the DGA driver will use doublebuffering, which results in much smoother movie replaying. It will tell you whether double- buffering is enabled or not.

    Doublebuffering means that the next frame of your video is being drawn in some offscreen memory while the current frame is being displayed. When the next frame is ready, the graphics chip is just told the location in memory of the new frame and simply fetches the data to be displayed from there. In the meantime the other buffer in memory will be filled again with new video data.

    Doublebuffering may be switched on by using the option -double and may be disabled with -nodouble. Current default option is to disable doublebuffering. When using the DGA driver, onscreen display (OSD) only works with doublebuffering enabled. However, enabling doublebuffering may result in a big speed penalty (on my K6-II+ 525 it used an additional 20% of CPU time!) depending on the implementation of DGA for your hardware.

    2.3.1.3.7. Speed issues

    Generally spoken, DGA framebuffer access should be at least as fast as using the X11 driver with the additional benefit of getting a fullscreen image. The percentage speed values printed by mplayer have to be interpreted with some care, as for example, with the X11 driver they do not include the time used by the X-Server needed for the actual drawing. Hook a terminal to a serial line of your box and start top to see what is really going on in your box ...

    Generally spoken, the speedup done by using DGA against 'normal' use of X11 highly depends on your graphics card and how well the X-Server module for it is optimized.

    If you have a slow system, better use 15 or 16bit depth since they require only half the memory bandwidth of a 32 bit display.

    Using a depth of 24bit is even a good idea if your card natively just supports 32 bit depth since it transfers 25% less data compared to the 32/32 mode.

    I've seen some avi files already be replayed on a Pentium MMX 266. AMD K6-2 CPUs might work at 400 MHZ and above.

    2.3.1.3.8. Known bugs

    Well, according to some developpers of XFree, DGA is quite a beast. They tell you better not to use it. Its implementation is not always flawless with every chipset driver for XFree out there.

    2.3.1.3.9. Future work

    2.3.1.3.A. Some modelines

      Section "Modes"
        Identifier    "Modes[0]"
        Modeline	"800x600"  40     800 840 968 1056  600 601 605 628
        Modeline	"712x600"  35.0   712 740 850 900   400 410 412 425
        Modeline	"640x480"  25.175 640 664 760 800   480 491 493 525
        Modeline 	"400x300"  20     400 416 480 528   300 301 303 314 Doublescan
        Modeline	"352x288"  25.10  352 368 416 432   288 296 290 310
        Modeline	"352x240"  15.750 352 368 416 432   240 244 246 262 Doublescan
        Modeline	"320x240"  12.588 320 336 384 400   240 245 246 262 Doublescan
      EndSection
    

    These entries work fine with my Riva128 chip, using nv.o XServer driver module.

    2.3.1.3.B. Bug Reports

    If you experience troubles with the DGA driver please feel free to file a bug report to me (e-mail address below). Please start mplayer with the -v option and include all lines in the bug report that start with vo_dga:

    Please do also include the version of X11 you are using, the graphics card and your CPU type. The X11 driver module (defined in XF86-Config) might also help. Thanks!

    Acki (acki@acki-netz.de, www.acki-netz.de)

    2.3.1.4. SDL

    Here are some notes about SDL out in MPlayer.

    There are several commandline switches for SDL:

      -vo sdl:name   specifies sdl video driver to use (ie. aalib, dga, x11)
    -ao sdl:namespecifies sdl audio driver to use (ie. dsp, esd, arts)
    -noxvdisables Xvideo hardware acceleration
    -forcexvtries to force Xvideo acceleration

    SDL Keys:

    Ftoggles fullscreen/windowed mode
    Ccycles available fullscreen modes
    W/Smappings for * and / (mixer control)

    KNOWN BUGS:

    2.3.1.5. SVGAlib

    If you don't have X, you can use the SVGAlib target! Be sure not to use the -fs switch, since it toggles the usage of the software scaler, and it's SLOOOW now, unless you have a real fast CPU (and/or MTRR?). :(

    Of course you'll have to install svgalib and its development package in order for MPlayer build its SVGAlib driver (autodetected, but can be forced), and don't forget to edit /etc/vga/libvga.config to suit your card & monitor.

    2.3.1.6. Framebuffer output (FBdev)

    Whether to build the FBdev target is autodetected during ./configure . Read the framebuffer documentation in the kernel sources (Documentation/fb/*) for info on how to enable it, etc.. !

    If your card doesn't support VBE 2.0 standard (older ISA/PCI cards, such as S3 Trio64), only VBE 1.2 (or older?) : Well, VESAfb is still available, but you'll have to load SciTech Display Doctor (formerly UniVBE) before booting Linux. Use a DOS boot disk or whatever. And don't forget to register your UniVBE ;))

    The FBdev output takes some additional parameters above the others:

      -fb   specify the framebuffer device to use (/dev/fd0)
    -fbmodemode name to use (according to /etc/fb.modes)
    -fbmodeconfig config file of modes (default /etc/fb.modes)
    -monitor_hfreqIMPORTANT values, see example.conf
    -monitor_vfreq
    -monitor_dotclock

    If you want to change to a specific mode, then use

        mplayer -vm -fbmode (NameOfMode) filename

    NOTE: FBdev video mode changing _does not work_ with the VESA framebuffer, and don't ask for it, since it's not an MPlayer limitation.

    2.3.1.7. Matrox framebuffer (mga_vid)

    This section is about the Matrox G200/G400/G450/G550 BES (Back-End Scaler) support, the mga_vid kernel driver. It's active developed by me (A'rpi), and it has hardware VSYNC support with triple buffering. It works on both framebuffer console and under X.

    To use it, you first have to compile mga_vid.o:

        cd drivers
        make

    Then create /dev/mga_vid device:

        mknod /dev/mga_vid c 178 0

    and load the driver with

        insmod mga_vid.o

    You should verify the memory size detection using the 'dmesg' command. If it's bad, use the mga_ram_size option (rmmod mga_vid first), specify card's memory size in MB:

        insmod mga_vid.o mga_ram_size=16

    To make it load/unload automatically when needed, insert the following line at the end of /etc/modules.conf:

        alias char-major-178 mga_vid

    Then run

        depmod -a

    Now you have to (re)compile MPlayer, ./configure will detect /dev/mga_vid and build the 'mga' driver. Using it from MPlayer goes by '-vo mga' if you have matroxfb console, or '-vo xmga' under XFree86 3.x.x or 4.x.x.

    The mga_vid driver cooperates with Xv.

    2.3.1.8. SiS 6326 framebuffer (sis_vid)

    SiS 6326 YUV Framebuffer driver -> sis_vid kernel driver

    Its interface should be compatible with the mga_vid, but the driver was not updated after the mga_vid changes, so it's outdated now. Volunteers needed to test it and bring the code up-to-date.

    2.3.1.9. 3dfx YUV support (tdfxfb)

    This driver uses the kernel's tdfx framebuffer driver to play movies with YUV acceleration. You'll need a kernel with tdfxfb support, and recompile with ./configure --enable-tdfxfb

    2.3.1.10. OpenGL output

    MPlayer support displaying movies using OpenGL. Unfortunately, not all drivers support this ability. For example the Utah-GLX drivers (for XFree86 3.3.6) have it, with all cards. See http://utah-glx.sourceforge.net for details about how to install it.

    XFree86(DRI) >= 4.0.3 supports it only with Matrox, and Radeon cards. See http://dri.sourceforge.net for download, and installation instructions.

    2.3.1.11. AAlib - text mode displaying

    AAlib is a library for displaying graphics in text mode, using powerful ASCII renderer. There are LOTS of programs already supporting it, like Doom, Quake, etc. MPlayer contains a very usable driver for it. If ./configure detects aalib installed, the aalib libvo driver will be built.

    You can use some keys in the AA Window to change rendering options:

      1  decrease contrast
    2increase contrast
    3decrease brightness
    4increase brightness
    5switch fast rendering on/off
    6set dithering mode (none, error distribution, floyd steinberg)
    7invert image
    atoggles between aa and mplayer control)

    The following command line options can be used:

    -aaosdcolor=Vchange osd color
    -aasubcolor=Vchange subtitle color

    where V can be: (0/normal, 1/dark, 2/bold, 3/boldfont, 4/reverse, 5/special)

    AAlib itselves provides a large sum of options. Here are some important:

    -aadriverset recommended aa driver (X11, curses, linux)
    -aaextendeduse all 256 characters
    -aaeightuse eight bit ascii
    -aahelpprints out all aalib options

    NOTE: the rendering is very CPU intensive, especially when using AA-on-X (using aalib on X), and it's least CPU intensive on standard, non-framebuffer console. Use SVGATextMode to set up a big textmode, then enjoy! (secondary head Hercules cards rock :)) (anyone can enhance bdev to do conversion/dithering to hgafb? Would be neat :)

    Use the -framedrop option if your comp isn't fast enough to render all frames!

    Playing on terminal you'll get better speed and quality using the linux driver, not curses (-aadriver linux). But therefore you need write access on /dev/vcsa<terminal>! That isn't autodetected by aalib, bu vo_aa tries to find the best mode. See http://aa-project.sourceforge.net/tune/ for further tuning issues.

    2.3.1.12. VESA - output to VESA BIOS

    This driver was designed and introduced as generic driver for any video card which has VESA VBE 2.0 compatible BIOS. But exists still one reason of developing of this driver - it's multiple troubles with displaying movie on TV.
    VESA BIOS EXTENSION (VBE) Version 3.0 Date: September 16, 1998 (Page 70) says:

    Dual-Controller Designs
    VBE 3.0 supports the dual-controller design by assuming that since both controllers are typically provided by the same OEM, under control of a single BIOS ROM on the same graphics card, it is possible to hide the fact that two controllers are indeed present from the application. This has the limitation of preventing simultaneous use of the independent controllers, but allows applications released before VBE 3.0 to operate normally. The VBE Function 00h (Return Controller Information) returns the combined information of both controllers, including the combined list of available modes. When the application selects a mode, the appropriate controller is activated. Each of the remaining VBE functions then operates on the active controller.

    So you have chances to get working TV-out by using this driver.
    (I guess that TV-out frequently is standalone head or standalone output at least.)

    What are pluses:
    - You have chances to watch movies if Linux even doesn't know your video hardware.
    - You don't need to have installed any graphics' related things on your Linux (like X11 (aka XFree86), fbdev and so on). This driver can be run from text-mode.
    - You have chances to get working TV-out. (It's known at least for ATI's cards).
    - This driver calls int 10h handler thus it's not an emulator - it calls real things of real BIOS in real-mode. (Finely - in vm86 mode).
    - Most important :) You can watch DVD at 320x200 if you don't have a powerful CPU.

    What are minuses:
    - It works only on x86 systems.
    - It's the slowest driver from all the available ones for MPlayer.
    (But only if your card doesn't support DGA mode - otherwise this driver is comparable by speed with -vo dga and -vo fbdev ones.
    - It can be used only by ROOT.
    - Currently it's available only for Linux.
    - It doesn't use any hardware accelerations (like YUV overlay or hw scaling).

    These switches of command line currently are available for VESA:

      -vo vesa:optscurrently recognized: dga to force dga mode and nodga to disable dga mode. Note: you may omit these parameters to enable autodetect of dga mode. (In the future also will specify mode parameters such as refresh rate, interlacing, doublescan and so on. Samples: i43, 85, d100)
    -screenw, -screenh, -bppforce userdefined mode
    -x, -yset userdefined prescaling
    -zoomenables userdefined prescaling
    -fsscales image to fullscreen
    -fs -zoomscales userdefined prescaling to fullscreen
    -doubleenables double buffering mode. (Available only in DGA mode). Should be slower of single buffering, but has no flickering effects.

    Known problems and workaround:
    - If you have installed NLS font on your Linux box and run VESA driver from text-mode then after terminating mplayer you will have ROM font loaded instead of national. You can load national font again by using setsysfont utility from for example Mandrake distribution.
    (Hint: The same utility is used for localizating fbdev).
    - Some Linux graphics drivers don't update active BIOS mode in DOS memory. So if you have such problem - always use VESA driver only from text-mode. Otherwise text-mode (#03) will be activated anyway and you will need restart your computer.
    - Often after terminating VESA driver you get black screen. To return your screen to original state - simply switch to other console (by pressing Alt-Fx) then switch to your previous console by the same way.
    - To get working TV-out you need have plugged tv-connector in before booting your PC since video BIOS initializes itself only once during POST procedure.

    2.3.1.13. X11

    Avoid if possible. Outputs to X11 (uses shared memory extension), with no hardware acceleration at all. Supports (MMX/3DNow/SSE accelerated, but still slow) software scaling, use the options -fs -zoom. Most cards have hardware scaling support, use the -vo xv output for them, or -vo xmga for Matroxes.

    The problem is that most cards' driver doesn't support hardware acceleration on the second head/TV. In those cases, you see green/blue coloured window instead of the movie. This is where this driver comes in handy, but you need powerful CPU to use software scaling. Don't use the SDL driver's software output+scaler, it has worse image quality !

    2.3.1.14. Radeon video overlay (radeon_vid)

    radeon_vid provides support for the BackEnd Scaler on ATI Radeon chipsets. It was designed and introduced as analog of mga_vid driver, so you can use it in the same way!
    But main goal of this driver usage is VESA driver.
    Simply because VESA enables TV-out on ATI's card but Backend scaler is used after mode switching. This implementation outputs video stream on both: TV-screen and CRTC display simultaneously. (It slightly degrades quality of video output but it's much better than nothing). Sorry! I couldn't find out any video overlay's related information on ATI pages. (I planned to implement it through int 10h calls). But it was very easy to implement this stuff through reading/writing Radeon ports.
    NOTE: XXX_VID technology is perfectly undocumented and maybe in the future this stuff will be fully rewritten. This is the first public release of driver.

    Installation


    Usage:
      mplayer -vo vesa:lvo:/dev/radeon_vid <your options> filename

    NOTE: don't use any framebuffers when you plan to use this driver ! Use it only from textmode console.

    Limitations: Currently it works only with YUY2 format, so use the DirectShow codec family with it. You should have at least 32MB of video memory.
    Conclusion: I know there are lot of lacks and bugs. So if you are able to improve something then simply send me your patches.

    2.3.1.A. TV-out support

    2.3.1.A.1. Matrox cards

    Under Linux you have 2 methods to get TV out working :

    2.3.1.A.2. ATI cards

    A few word about ATI's TV-out:
    Currently ATI doesn't want to support any of its TV-out chips under Linux. Below is official answer from ATI Inc.:


    > Hello!
    >
    > On your pages you wrote that you support linux developers.
    > Currently I participate with mplayer project (www.mplayerhq.hu)
    > I'm interesting with enabling TV-out on Radeon VE chips during
    > movie playback. I would be glad to add this feature to radeonfb driver
    > (which can be found in CVS tree of mplayer project at main/drivers/radeon).
    > Do I have a chance to get any official technical documenation?

    We will not provide TV out related documents due to macrovision concerns.
    Also mpeg2 decoding is something that we MAY consider in the future but not
    at this current time. This is again due to proprietary and 3rd party
    information.

    Pity isn't?

    Q:What is Macrovision?
    A:It's copy protection mechanism.

    It means that if they open any TV-out related information then hackers will be able to disable copy protection on their chips. Therefore we have no chance to get working TV-out on ATI.

    What's status of ATI's tv-out chips under Linux:

  • ATI Mach64 has ImpacTV which is supported by gatos.
  • ASIC Radeon VIVO has Rage Theatre which is supported by gatos.
  • Radeon VE and Rage PRO LT have ImpacTV2+ which is not supported under Linux.

    Fortunately, owners of fast enough CPUs (Duron, Celeron2 and better) can watch movies on their TV through VESA drivers.

    I should say good words to ATI Inc. too:
    they produce top quality BIOSes.

    VESA drivers don't use any hardware acceleration but it simulates DGA through 64K window, which is configured through 32-bit mode functions of BIOS. ATI cards have enough fast video memory (DIMM or DDR chips with 64 - 128-bit access) so it's not bottleneck for them. There are no limitations on which video mode can be displayed on your TV (like on other cards) so you can use any video mode on your TV (from 320x200 up to 1024x768).
    From other side (it's known at least for Radeons) there is DGA mode which is detected automatically and in this case you'll get comparable with -vo dga and -vo fbdev drivers speed.
    Only thing you need to do - have TV connector plugged in before booting your PC since video BIOS initializes itself only once during POST procedure.

    For detail see VESA sections of this documentation.

    2.3.1.A.4. Voodoo 3

    Check this URL.