| This file contains information about the implementation of the | |
| multimedia layer of WINE. The libraries consist of MMSYSTEM.DLL | |
| (win16), WINMM.DLL (win32) and some (abstracted, not Windows | |
| compatible) low level drivers. | |
| The implementation can be found in the dlls/winmm/ sub directory. | |
| 0. Overview | |
| =========== | |
| The multimedia stuff is split into 3 layers. The low level (device | |
| drivers), mid level (MCI commands) and high level abstraction layers. | |
| The low level may depend on current hardware and OS services (like | |
| OSS). Mid level (MCI) and high level must be written independently | |
| from the hardware and OS services. | |
| There are two specific low level drivers call mappers (for wave and | |
| +midi) whose role is to : | |
| * help choosing one low level driver between many | |
| * add the possibility to convert stream (ie ADPCM => PCM) | |
| * add the possibility to filter a stream (adding echo, equalizer...) | |
| All of those components are defined as DLLs (one by one) and are | |
| candidate for dllglue migration. | |
| 1. Low level layers | |
| =================== | |
| Please note that native low level drivers are not currently supported | |
| in WINE, because they either access hardware components or require | |
| VxDs to be loaded; WINE does not correctly supports those two so far. | |
| The following low level layers are implemented: | |
| 1.1 (Wave form) Audio | |
| --------------------- | |
| MMSYSTEM and WINMM call the real low level audio driver using the | |
| wodMessage/widMessage which handles the different requests. | |
| 1.1.1 OSS implementation | |
| The low level audio driver is currently only implemented for the | |
| OpenSoundSystem (OSS) as supplied in the Linux and FreeBSD kernels by | |
| [1]4Front Technologies. The presence of this driver is checked by | |
| configure (depends on the <sys/soundcard.h> file). Source code resides | |
| in dlls/winmm/wineoss/audio.c, | |
| The implementation contains all features commonly used, but has | |
| several problems (see TODO list). | |
| TODO: | |
| * add asynchronous reads [recording] (must use threads) as done for | |
| writes [playing] | |
| * verify all functions for correctness | |
| * looping of WaveHdr will fail | |
| * share access to /dev/dsp with dsound interface (either on a | |
| descriptor basis, or using a virtual mixer between different wave | |
| inputs. EsounD provides this type of capability). | |
| 1.1.2 Other sub systems | |
| None are available. Could think of Sun Audio, remote audio systems | |
| (using X extensions, ...), ALSA, EsounD | |
| 1.2 MIDI | |
| -------- | |
| MMSYSTEM and WINMM call the low level driver functions using the | |
| midMessage and the modMessage functions. | |
| 1.2.1 OSS driver | |
| The low level audio driver is currently only implemented for the | |
| OpenSoundSystem (OSS) as supplied in the Linux and FreeBSD kernels by | |
| [1]4Front Technologies . The presence of this driver is checked by | |
| configure (depends on the <sys/soundcard.h> file, and also some | |
| specific defines because MIDI is not supported on all OSes by OSS). | |
| Source code resides in dlls/winmm/wineoss/midi.c | |
| Both Midi in and Midi out are provided. The type of MIDI devices | |
| supported is external MIDI port (requires an MIDI capable device - | |
| keyboard...) and OPL/2 synthesis (the OPL/2 patches for all | |
| instruments are in midiPatch.c). | |
| TODO: | |
| * use better instrument definition for OPL/2 (midiPatch.c) or use | |
| existing instrument definition (from playmidi or kmid) with a | |
| .winerc option | |
| * have a look at OPL/3 ? | |
| * implement asynchronous playback of MidiHdr | |
| * implement STREAM'ed MidiHdr (question: how shall we share the code | |
| between the midiStream functions in MMSYSTEM/WINMM and the code | |
| for the low level driver) | |
| * use a more accurate read mechanism than the one of snooping on | |
| timers (like select on fd) | |
| 1.2.2 Other sub systems | |
| Could support other midi implementation for other sub systems (any | |
| idea here ?) | |
| Could also implement a software synthesizer, either inside Wine or | |
| using using MIDI loop back devices in an external program (like | |
| timidity). The only trouble is that timidity is GPL'ed... | |
| 1.3 Mixer | |
| --------- | |
| MMSYSTEM and WINMM call the low level driver functions using the | |
| mixMessage function. | |
| 1.3.1 OSS implementation | |
| The current implementation uses the OpenSoundSystem mixer, and resides | |
| in dlls/winmm/wineoss/mixer.c | |
| TODO: | |
| * implement notification mechanism when state of mixer's controls | |
| change | |
| 1.3.2 Other sub systems | |
| TODO: | |
| * implement mixing low level drivers for other mixers (ALSA...) | |
| 1.4 AUX | |
| ------- | |
| The AUX low level driver is the predecessor of the mixer driver | |
| (introduced in Win 95). | |
| 1.4.1 OSS driver | |
| The implementation uses the OSS mixer API, and is incomplete. | |
| TODO: | |
| * verify the implementation | |
| * check with what is done in mixer | |
| * open question: shall we implement it on top of the low level mixer | |
| functions ? | |
| 1.5 Joystick | |
| ------------ | |
| The API consists of the joy* functions found in dlls/winmm/joystick.c. | |
| The implementation currently uses the Linux joystick device driver | |
| API. It is lacking support for enhanced joysticks and has not been | |
| extensively tested. | |
| TODO: | |
| * better support of enhanced joysticks | |
| * support more joystick drivers (like the XInput extension) | |
| * should make joystick a separate DLL (impact also on | |
| WINMM/MMSYSTEM), or a real low level driver, as it is on Windows | |
| 1.6 Wave mapper (msacm.drv) | |
| --------------------------- | |
| The Wave mapper device allows to load on-demand codecs in order to | |
| perform software conversion for the types the actual low level driver | |
| (hardware). Those codecs are provided through the standard ACM | |
| drivers. | |
| 1.6.1 Build-in | |
| A first working implementation for wave out as been provided (wave in | |
| exists, but doesn't allow conversion). | |
| Wave mapper driver implementation can be found in dlls/winmm/wavemap/ | |
| directory. This driver heavily relies on MSACM and MSACM32 DLLs which | |
| can be found in dlls/msacm and dlls/msacm32. Those DLLs load ACM | |
| drivers which provide the conversion to PCM format (which is normally | |
| supported by low level drivers). ADPCM, MP3... fit into the category | |
| of non PCM formats. | |
| There is currently no builtin ACM driver in Wine, so you must use | |
| native ones if you're looking for non PCM playback. | |
| In order to use native ACM drivers to play non PCM files, you must use | |
| -dll msacm,msacm32,msacm.drv=b. Note that this code is not complete | |
| yet, and may cause problems. sndrec32 and mplayer from Win95 appear to | |
| work reasonably well though. | |
| TODO: | |
| * do wave in | |
| * check for correctness and robustness | |
| 1.6.2 Native | |
| Seems to work quite ok (using of course native MSACM/MSACM32 DLLs) | |
| Some other testings report some issues while reading back the registry | |
| settings. | |
| 1.7 MIDI mapper | |
| --------------- | |
| Midi mapper allows to map each one of 16 MIDI channels to a specific | |
| instrument on an installed sound card. This allows for example to | |
| support different MIDI instrument definition (XM, GM...). It also | |
| permits to output on a per channel basis to different MIDI renderers. | |
| 1.7.1 Built-in | |
| A builtin MIDI mapper can be found in dlls/winmm/midimap. It only | |
| provides the pickup of an existing MIDI low level driver for playback. | |
| TODO: | |
| * implement the Midi mapper features (channel / instrument on the | |
| fly modification) | |
| 1.7.2 Native | |
| Currently, the native midimapper i'm using is not working (mainly | |
| because it reads low level drivers configuration from registry). | |
| TODO: | |
| * let native midimapper driver load | |
| 2. Mid level drivers (MCI) | |
| ========================== | |
| The mid level drivers are represented by some common API functions, | |
| mostly mciSendCommand and mciSendString. See status in chapter 3 for | |
| more information. WINE implements several MCI mid level drivers | |
| (status is given for both built-in and native implementation): | |
| TODO: (apply to all built-in MCI drivers) | |
| * use mmsystem multitasking caps instead of the home grown | |
| 2.1 CDAUDIO | |
| ----------- | |
| 2.1.1 Built-in | |
| The currently best implementation is the MCI CDAUDIO driver that can | |
| be found in dlls/winmm/mcicda/mcicda.c. The implementation is mostly | |
| complete, there have been no reports of errors. It makes use of | |
| misc/cdrom.c Wine internal cdrom interface. | |
| This interface has been ported on Linux, FreeBSD and NetBSD. (Sun | |
| should be similar, but are not implemented.) | |
| A very small example of a cdplayer consists just of the line | |
| mciSendString("play cdaudio",NULL,0,0); | |
| TODO: | |
| * add support for other cdaudio drivers (Solaris...) | |
| * add support for multiple cdaudio devices | |
| 2.1.2 Native | |
| Native MCICDA works also correctly... It uses the mscdex traps (on int | |
| 2f). | |
| 2.2 MCIWAVE | |
| ----------- | |
| 2.2.1 Built-in | |
| The implementation is rather complete and can be found in | |
| dlls/winmm/mciwave/audio.c. It uses the low level audio API (although | |
| not abstracted correctly). | |
| FIXME: | |
| * The MCI_STATUS command is broken. | |
| TODO: | |
| * check for correctness | |
| * better use of asynchronous playback from low level | |
| * record has to be checked | |
| * MCI_CUE command is broken | |
| * better implement non waiting command (without the MCI_WAIT flag). | |
| 2.2.2 Native | |
| Native MCIWAVE works also correctly. | |
| 2.3 MCISEQ (MIDI sequencer) | |
| --------------------------- | |
| 2.3.1 Built-in | |
| The implementation can be found in dlls/winmm/mciseq/mcimidi.c. Except | |
| from the Record command, should be close to completion (except for non | |
| blocking commands). | |
| TODO: | |
| * implement it correctly | |
| * finish asynchronous commands (especially for reading/record) | |
| * better implement non waiting command (without the MCI_WAIT flag). | |
| 2.3.2 Native | |
| Native MCIMIDI has been working but is currently blocked by scheduling | |
| issues (mmTaskXXX no longer work). | |
| FIXME: | |
| * midiStreamPlay get from time to time an incorrect MidiHdr when | |
| using the native MCI sequencer | |
| 2.4 MCIANIM | |
| ----------- | |
| 2.4.1 Built-in | |
| The implementation consists of stubs and is in dlls/winmm/mcianim.c. | |
| TODO: | |
| * implement it, probably using xanim or something similar. | |
| 2.4.2 Native | |
| Native MCIANIM is reported to work (but requires native video DLLs | |
| also). | |
| 2.5 MCIAVI | |
| ---------- | |
| 2.5.1 Built-in | |
| The implementation consists of stubs and is in | |
| dlls/winmm/mciavi/mciavi.c. | |
| TODO: | |
| * implement it, probably using xanim or something similar. | |
| 2.5.2 Native | |
| Native MCIAVI is reported to work (but requires native video DLLs | |
| also). Some files exhibit some deadlock issues anyway. | |
| 3 High level layers | |
| =================== | |
| The rest (basically the MMSYSTEM and WINMM DLLs entry points). It also | |
| provides the skeleton for the core functionality for multimedia | |
| rendering. Note that native MMSYSTEM and WINMM do not currently work | |
| under WINE and there is no plan to support them (it would require to | |
| also fully support VxD, which is not done yet). | |
| MCI and low level drivers can either be 16 or 32 bit. | |
| TODO: | |
| * it seems that some program check what's installed in registry | |
| against value returned by drivers. Wine is currently broken | |
| regarding this point. | |
| * add clean-up mechanisms when process detaches from MM DLLs | |
| * prepare for the 16/32 big split | |
| * check thread-safeness for MMSYSTEM and WINMM entry points | |
| * unicode entry points are badly supported | |
| 3.1 MCI skeleton | |
| ---------------- | |
| Implementation of what is needed to load/unload MCI drivers, and to | |
| pass correct information to them. This is implemented in | |
| dlls/winmm/mci.c. The mciSendString function uses command strings, | |
| which are translated into normal MCI commands as used by | |
| mciSendCommand with the help of command tables. The API can be found | |
| in dlls/winmm/mmsystem.c and dlls/winmm/mci.c. The functions there | |
| (mciOpen,mciSysInfo) handle mid level driver allocation and calls. The | |
| implementation is not complete. | |
| MCI drivers are seen as regular WINE modules, and can be loaded (with | |
| a correct load order between built-in, native, elfdll, so), as any | |
| other DLL. Please note, that MCI drivers module names must bear the | |
| .drv extension to be correctly understood. | |
| The list of available MCI drivers is obtained as follows: | |
| 1. key 'mci' in [option] section from .winerc (or wineconf) | |
| mci=CDAUDIO:SEQUENCER gives the list of MCI drivers (names, in | |
| uppercase only) to be used in WINE. | |
| 2. This list, when defined, supersedes the mci key in | |
| c:\windows\system.ini | |
| Note that native VIDEODISC crashes when the module is loaded, which | |
| occurs when the MCI procedures are initialised. Make sure that this is | |
| not in the list from above. Try adding: | |
| mci=CDAUDIO:SEQUENCER:WAVEAUDIO:AVIVIDEO:MPEGVIDEO | |
| to the [options] section of wine.conf. | |
| TODO: | |
| * correctly handle the MCI_ALL_DEVICE_ID in functions. | |
| * finish mapping 16 <=> 32 of MCI structures and commands | |
| * MCI_SOUND is not handled correctly (should not be sent to MCI | |
| driver => same behavior as MCI_BREAK) | |
| * do not display module warning when failed to 32-bit load a 16 bit | |
| module when 16 bit load can succeed (and the other way around) | |
| * implement auto-open feature (ie, when a string command is issued | |
| for a not yet opened device, MCI automatically opens it) | |
| 3.2 MCI multi-tasking | |
| --------------------- | |
| Multi-tasking capabilities used for the MCI drivers are provided in | |
| dlls/winmm/mmsystem.c. | |
| TODO: | |
| mmTaskXXX functions are currently broken because the 16 loader does | |
| not support binary command lines => provide Wine's own mmtask.tsk not | |
| using binary command line. | |
| the Wine native MCI drivers should use the mmThreadXXX API and no | |
| longer use the MCI_AsyncCommand hack. | |
| 3.3 Timers | |
| ---------- | |
| It currently uses a service thread, run in the context of the calling | |
| process, which should correctly mimic Windows behavior. | |
| TODO: | |
| * Check if minimal time is satisfactory for most programs. | |
| * current implementation may let a timer tick (once) after it has | |
| been destroyed | |
| 3.4 MMIO | |
| -------- | |
| The API consists of the mmio* functions found in mdlls/winmm/mmio.c. | |
| Seems to work ok in most of the cases. There's some linear/segmented | |
| issues with 16 bit code. | |
| 3.5 sndPlayXXX functions | |
| ------------------------ | |
| Seem to work correctly. | |
| 4 Multimedia configuration | |
| ========================== | |
| Currently, multimedia configuration heavily relies on Win 3.x | |
| configuration model. | |
| 4.1 Drivers | |
| ----------- | |
| Since all multimedia drivers (MCI, low level ones, ACM drivers, | |
| mappers) are, at first, drivers they need to appear in the [mci] or | |
| [mci32] section of the system.ini file. | |
| Since all drivers are, at first, DLLs, you can choose to load their | |
| Wine's (builtin) or Windows (native) version. | |
| 4.2 MCI | |
| ------- | |
| A default [mci] section (in system.ini) looks like (see the note above | |
| on videodisc): | |
| [mci] | |
| cdaudio=mcicda.drv | |
| sequencer=mciseq.drv | |
| waveaudio=mciwave.drv | |
| avivideo=mciavi.drv | |
| videodisc=mcipionr.drv | |
| vcr=mcivisca.drv | |
| MPEGVideo=mciqtz.drv | |
| By default, the list of loadable MCI drivers will be made of those | |
| drivers (in the [mci] section). | |
| The list of loadable (recognized) MCI drivers can be altered in the | |
| [option] section of wine.conf, like: | |
| mci=CDAUDIO:SEQUENCER:WAVEAUDIO:AVIVIDEO:MPEGVIDEO | |
| TODO: | |
| use a default registry setting to bypass this (ugly) configuration | |
| model | |
| 4.3 Low level drivers | |
| --------------------- | |
| They are currently hardcoded in dlls/winmm/lolvldrv.c. | |
| TODO: | |
| use a default registry setting to provide a decent configuration | |
| model. this shall also help some programs to work (some of them test | |
| the names returned by low level drivers with the ones defined and | |
| installed in the registry) | |
| 4.4 ACM | |
| ------- | |
| To be done (use the same mechanism as MCI drivers configuration). | |
| 5 Multimedia architecture | |
| ========================= | |
| 5.1 Windows 9x multimedia architecture | |
| -------------------------------------- | |
| | | |
| Kernel space | Client applications | |
| | | |
| | | | ^ ^ | | | | | |
| | 16>| |<32 16>| |<32 16>| |<32 16>| |<32 | |
| | | v | | | v | v | |
| | +----|-----------|---------|------------|-------+ | |
| | | | | | | | WinMM.dll | |
| | | | | | | | 32 bit | |
| | +----|-----------|---------|------------|-------+ | |
| | | | | ^ | | | | |
| | +------+ | |<16 | | | |<16 | | |
| | | 16>| | | | | | | | | |
| | | v v v | | v v v | |
| | | +---------------+---+-------------+-------------+ | |
| | | | waveInXXX | | mciXXX | *playSound* | | |
| | | | waveOutXXX | | | mmioXXX | | |
| | | | midiInXXX | | | timeXXX | | |
| | | | midiOutXXX | | | driverXXX | | |
| | | | midiStreamXXX | | | | MMSystem.dll | |
| | | | mixerXXX | | | | 16 bit | |
| +--------+ | | | auxXXX +---+ +---+ mmThread| | | |
| |MMDEVLDR|<------->| joyXXX | Call back | mmTask | | | |
| +--------+ | | +-----------+-----------+---------+-------------+ | |
| ^ | | | ^ ^ | ^ | |
| | | | 16>| |<16>| 16>| |<16 | |
| v | | v | | v | | |
| +--------+ | | +-------------+ +----------+ | |
| | VxD |<------->| .drv | | mci*.drv | | |
| +--------+ | | +--------------+ +-----------+ | |
| | | | msacmm.drv | | mciwave | | |
| | | +--------------+ +-----------+ | |
| | | | midimap.drv | | mcimidi | | |
| | | +-------------+ +-----------+ | |
| | | Low-level drivers | ... | MCI drivers | |
| | | +----------+ | |
| | | | | |
| | | |<16 | |
| | +-------------------------------+ | |
| | | |
| The important points to notice are: | |
| * all drivers (and most of the core code) is 16 bit | |
| * all hardware (or most of it) dependant code reside in the kernel | |
| space (which is not surprising) | |
| 5.2 Wine multimedia architecture | |
| -------------------------------- | |
| | | |
| Kernel space | Client applications | |
| | | |
| | | | ^ ^ | | | | | |
| | 16>| |<32 16>| |<32 16>| |<32 16>| |<32 | |
| | | | | | | | | | | |
| | +------+ | | | | | | | | | |
| | |32/16>| | | | | | | | | | |
| | | v v v | | v v v v | |
| | | +---------------+---+-------------+-------------+ | |
| | | | waveInXXX | | mciXXX | *playSound* | | |
| | | | waveOutXXX | | | mmioXXX | WinMM.dll | |
| | | | midiInXXX | | | timeXXX | 32 bit | |
| | | | midiOutXXX | | | driverXXX | | |
| | | | midiStreamXXX | | | | MSystem.dll | |
| | | | mixerXXX | | | | 16 bit | |
| | | | auxXXX +---+ +---+ mmThread| | | |
| | | | joyXXX | Call back | mmTask | | | |
| | | +-----------+-----------+---------+-------------+ | |
| | | | | ^ ^ || ^^ | |
| | | 16>| |<32 |<16>| 16>||<32>||<16 | |
| | | v v |<32>| vv || | |
| +---------+ | | +-------------+ +----------+ | |
| |HW driver|<------->| .drv | | mci*.drv | | |
| +---------+ | | +--------------+ +-----------+ | |
| | | | msacmm.drv | | mciwave | | |
| | | +--------------+ +-----------+ | |
| | | | midimap.drv | | mcimidi | | |
| | | +-------------+ +-----------+ | |
| | | Low-level drivers | ... | MCI drivers | |
| | | +----------+ | |
| | | | | |
| | | |<32/16 | |
| | +-------------------------------+ | |
| | | |
| From the previous drawings, the most noticeable difference are: | |
| * low-level drivers can either be 16 or 32 bit | |
| * MCI drivers can either be 16 or 32 bit | |
| * MMSystem and WinMM will be hosted in a single elfglue library | |
| * no link between the MMSystem/WinMM pair on kernel space shall | |
| exist. For example, there will be a low level driver to talk to a | |
| UNIX OSS (Open Sound System) driver | |
| * all built-in drivers (low-level and MCI) will be written as 32 bit | |
| drivers | |
| all native drivers will be 16 bits drivers | |
| ______________________________________________________ | |
| Last updated: 6, December 1999 | |
| By: Eric Pouech (eric.pouech@wanadoo.fr) | |
| References | |
| 1. http://www.4front-tech.com/ |