Waveform Audio Media Control Driver DLL (AUDIOMCT.DLL)

Following describes the files and messages that are processed in in the AUDIOMCT.DLL.

File

Description
ADMCOPEN.C
Processes the MCI_OPEN message. On an MCI_OPEN, a streaming MCD should perform the following actions: 1. Check flags and validate pointers.
2. Get default values from the INI files (if necessary).
3. Process MCI_OPEN_PLAYLIST (if supported).
4. Process MCI_OPEN_MMIO (if supported).
5. Process MCI_OPEN_ELEMENT (if supported).
6. Connect to the amp/mixer.
7. Get the stream protocol key (if necessary).

LOADSUBS.C
Provides various utility functions used by MCI_OPEN and MCI_LOAD including: 1. Creating temporary filenames (CheckForValidElement)
2. Aborting in process commands (LoadAbortNotify)
3. Processing the OPEN_MMIO flag (OpenHandle)
4. Rational as to when to open the card in record or playback mode (OpenHandle) (ProcessElement).
5. Processing temp files (ProcessElement).
6. Opening a file with MMIO (ProcessElement).
7. Processing the MCI_READ_ONLY flag (ProcessElement).
8. Creating a temporary file ( SetupTempFiles).
9. Using mmioSendMessage API to talk to an IOProc (SetupTempFiles).
10.Retrieving a connection and opening the connected device.
11.Stream Handler Setup (StreamSetup)
12.Processing MCI_NOTIFY or MCI_WAIT and callback handles (NotifyWaitSet up).

AUDIOMCD.C
Processes the MCIDRV_RESTORE message. A streaming MCD will receive a restore message when it regains control of the device they are attached to (for example, someone quit another application causing us to gain use of the device). On a restore, the MCD should check to see if it is in a paused state. If so, resume the stream.
Processes the MCIDRV_SAVE message. A streaming MCD will receive a save message when it loses control of the device it is attached to (for example, someone started another application which takes over the waveaudio device). On a save, the MCD should check to see if the MCD is currently streaming (either record or playback). If so, pause the stream, and set a flag stating that the MCD was saved.
ADMCLOAD.C
Processes the MCI_LOAD message. This file illustrates the following concepts: 1. How to check flags on a load.
2. How to stop any commands which are in process.
3. Why cuepoints/positionadvises need to be turned off on a MCI_LOAD.
4. Handling OPEN_MMIO on an MCI_LOAD.
5. Why reassociation of a stream on MCI_LOAD is desirable and
when it is appropriate.

ADMCCAP.C
Processes the MCI_GETDEVCAPS message. This file illustrates several concepts used to handle MCI_GETDEVCAPS including: 1. How to process the capability message commands.
These are messages which this MCD supports (such as play, close etc.)
Messages (or commands to the caller) such as sysinfo are
not supported by this MCD.
2. How to process the capability item flag.
Items describe particular features (such as the ability to record)
which the MCD either does or does not support.

ADMCSTAT.C
Processes the MCI_STATUS message. This file illustrates several concepts used to handle MCI_STATUS including: 1. When/If to report media position within a stream.
2. How to determine the length of an existing file.
3. How to determine the length of a file which is currently
being recorded.
4. Communicating with the amp/mixer to determine volume,
and other amplifier specific commands.
5. Reporting our current mode.
6. Reporting the current time format.

ADMCCUE.C
Processes the MCI_CUE message. Applications will typically call MCI_CUE in order to reduce the time required to begin the initial record or play. To a streaming MCD, MCI_CUE translates to an SPI_START_PREROLL. The start preroll will fill up all of the initial streaming buffers but will not start the stream. Then, when MCI_PLAY or MCI_RECORD are called, when they do an SpiStartStream then stream can start immediately.

On an MCI_CUE, a streaming MCD should perform the following actions: 1. Check flags and validate pointers.
2. Check to see if the stream is already in cue state. If it is, then
just return success.
3. If the caller wants to cue for output, execute the following:
a. stop any in process commands.
b. If the stream is going in the wrong direction (that is, record),
destroy it.
c. Create the stream if necessary.
d. Preroll start the stream.

4. If the caller wants to cue for input, execute the following:
a. Stop any in process commands.
b. If the stream is going in the wrong direction, destroy it.
c. Create the stream if necessary.
d. Preroll start the stream.


• Processes the MCI_SET_CUEPOINT message. On a MCI_SET_CUEPOINT, a streaming MCD should perform the following actions: 1. Check flags and validate pointers.
  2. Turn the cuepoint on or off depending on what flags are passed in.
  

  ADMCSEEK.C

  Processes the MCI_SEEK message. On a seek, a streaming MCD should perform the following actions: 1. Verify that the flags passed are valid.
  2. Verify the MCI_FROM, MCI_TO parameter if they were passed in.
  3. Ensure that any pointers passed are valid.
  4. Stop any commands which are active on another thread.
  5. If no stream has been created, then create one.
  6. If a stream had previously been created, ensure that it is in
  stopped state.
  
  ADMCPLAY.C
  Processes the MCI_PLAY message. On a MCI_PLAY, a streaming MCD should perform the following actions: 1. Always check flags and validate memory first. This way,
  if the flags are invalid, the previous command will not be interrupted.
  2. If there is a command active on another thread (that is, a play,
  record or save), then either abort (record or save) or supersede
  (play) by stopping the stream and sending a message to the caller.
  3. If the stream is going the wrong way (for example,
  it is set up for recording) then destroy the stream.
  4. If no stream has been created, then create one. If the stream handler
  needs to associate a data object, do it here.
  5. If we destroyed a recording stream before creating the play back stream,
  ensure that playback stream has the same position as the previous
  record stream.
  6. Enable any events (such as cuepoints or position advises).
  7. Start stream.
  8. Wait for a streaming event.
  9. Stop the stream if necessary.
  10.If MCI_NOTIFY was sent used, inform the caller of command completion.
  
  ADMCRECD.C
  Processes the MCI_RECORD message. On a MCI_RECORD, a streaming MCD should perform the following actions: 1. Always check flags and validate memory first. This way, if the flags
  are invalid, the previous command will not be interrupted.
  2. If there is a command active on another thread (that is,
  a play, record or save), then either abort (play or save)
  or supersede (record) by stopping the stream and sending
  a message to the caller.
  3. If the stream is going the wrong way (for example,
  it is setup for playback) then destroy the stream.
  4. If no stream has been created, then create one. If the stream handler
  needs to associate a data object, do it here.
  5. If we destroyed a play back stream before creating the record stream,
  seek to the same position in the record stream where the play back
  stream was.
  6. Enable any events (such as cuepoints or position advises).
  7. Start stream.
  8. Wait for a streaming event.
  9. Stop the stream if necessary.
  10.If MCI_NOTIFY was sent used, inform the caller of command completion.
  
  ADMCCLOS.C
  Processes the MCI_CLOSE message. On a close, a streaming MCD must perform the following actions: 1. Stop all commands which are active on another thread(s).
  2. Destroy all active streams.
  3. Close all open files.
  4. Delete any temporary files.
  5. Close any connected devices (such as an amp-mixer).
  6. If MCI_NOTIFY was used, notify the caller of completion.
  
  ADMCCONN.C
  Processes the MCI_CONNECTOR message. This source file illustrates how to enable, disable and query connectors. It also illustrates how to pass messages on to a connected MCD.
  ADMCREST.C
  Processes the MCI_STOP message. On a stop, a streaming MCD should perform the following actions: 1. Verify that the flags passed are valid.
  2. Stop any commands which are active on another thread.
  3. If a stream had previously been created, ensure that it is in
  stopped state.
  4. If it is a paused stream, then do a STOP_PAUSE to ensure that
  no data will be lost.
  
• Processes the MCI_RESUME message. On a MCI_RESUME, a streaming MCD should perform the following actions: 1. Ensure that no flags are passed in.
  2. If we are paused, resume the stream.
  

• Processes the MCI_SETPOSITIONADVISE message. To a streaming MCD, a position advise simply is a cuepoint which reoccurs every x time units. To enable position advise, the following steps should be followed: 1. Check flags and validate and pointers.
  2. If the caller has asked for position advise to be turned on then
  a. If a stream has been created, then enable the recurring cuepoint
  event.
  b. Else, set a flag and enable the event later.
  3. If position advise is to be turned off, then disable the recurring
  cuepoint event.
  

• Processes the MCI_PAUSE message. On a MCI_PAUSE, a streaming MCD should perform the following actions: 1. Ensure that no flags are passed in.
  2. If we are currently streaming, pause the stream.
  3. Set flag indicating that we are in paused state.
  

  ADMCSAVE.C

  Processes the MCI_SAVE message. MCI_SAVE is not a required command, however, if a streaming MCD takes advantage of temporary files, then it should use MCI_SAVE. 1. Ensure that the flags are valid.
  2. Then ensure that all pointers point to valid memory.
  3. If any operations are currently active, they are then
  aborted.
  4. Finally, the save operation itself is then done.
  
  AUDIOSUB.C
  Contains various utility functions including: 1. Correct processing of notifications.
  2. Handling calls the are neither MCI_WAIT or MCI_NOTIFY (PostMDMMessage).
  3. Using mmioGetHeader to obtain audio settings from a file (GetHeader).
  4. Creating a playlist stream (AssociatePlaylist).
  5. Installing an IOProc (InstallIOProc).
  6. Communicating with IOProcs with different capabilities (OpenFile).
  7. Processing audio files with various file formats (OpenFile).
  8. Time format conversion (ConvertToMM + ConvertTimeFormat).
  9. Creating an SPI stream (CreateNAssociateStream)
  10.Associating an SPI stream (CreateNAssociateStream)
  11.Setting an event for use in play to/record to (DoTillEvent).
  
  ADMCPST.C
  Processes the MCI_PASTE message. This file illustrates using MMIO functions and clipboard functions to: 1. Process the MCI_FROM_BUFFER flag or MCI_TO_BUFFER.
  2. Handle default positioning if no MCI_FROM/MCI_TO flags are
  passed
  3. Use MMIO to insert information into a file.
  
  ADMCCOPY.C
  Processes the MCI_COPY, MCI_DELETE, MCI_CUT, MCI_UNDO and MCI_REDO messages. It is a generic routine which handles placing information into the clipboard: 1. Default positioning for cut/copy/delete messages.
  2. Using MMIOM_DELETE to remove information from a file.
  3. Positioning after a cut/copy/delete
  4. Using MMIOM_UNDO and MMIOM_REDO messages.
  
  ADMCEDIT.C
  Contains utilities used by clipboard functions (such as cut and copy). The file illustrates: 1. How to Process MCI_FROM / MCI_TO for edit operations (CheckEditFlags) .
  2. Determine default from/to positions.
  3. Generic stream abort routine
  4. Retrieving information from the clipboard.
  5. Placing information into the clipboard.
  6. Using MMIO memory files to manipulate clipboard data.
  
  ADMCINI.C
  Illustrates how to parse device specific parms from the INI file.
  STRMSUBS.C
  Contains streaming subroutines used by play, record and cue. 1. How to close mmio files, and temp files (CloseFile).
  2. How to stop a record/playback stream (StopStream).
  3. How to use a semaphore to protect in progress commands
  from being aborted in sensitive areas.
  4. Why a stream must be destroyed after an MCI_SET (DestroySetStream).
  5. How to handle superseding and aborting of notifies.
  6. How and why to set a cue time pause event for
  MCI_TO (ProcessFromToFlags).
  7. How to enable cuepoints and positionchanges (EnableEvents).
  8. Networking functions (BeginQualityOfService, EndQualityOfService)
  

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