MultiMedia

How do you record sound from your sound card?

Visual Basic | Delphi | C++ Builder | Windows API | References

Visual Basic 6.0

Right click the Toolbox and select Components...
Under Controls, you can selct

Microsoft Multimedia Control 6.0 - MCI32.OCX the butons look identical to the Delphi TMediaPlayer component (though the order is different). It also appears to have the same limitations (see below), but I haven't tested that. Must be distributed with your application - 194K.
Windows Media Player - MSDXM.OCX which can play movies.

Under Insertable Objects, you can selct

Wave Sound - sndrec32.exe which has no properties.

Delphi

Delphi 5 - There are no components which support recording sounds.

There are no examples of recording sounds from the standard microphone input because it doesn't work very logically. The following works (sort of)

Create an *.wav file - test.wav - must right click and select New / Wave Sound. This writes the correct header to the file.
Place a System / MediaPlayer component on a form
Set the MediaPlayer1.FileName property
In FormActivate, add MediaPlayer1.open;
Run the form - use the Record and Play buttons

But MediaPlayer1.Save erases the file, and the program won't run again (because the format information was lost).

According to the Borland web site, Delphi 5 contains a design error in the MPlayer unit - Open fails for Wave Audio. So I downloaded Upgrade 1 (26 megs). Well, that was a waste of time.

  Old  mplayer.dcu 9-11-99
  New  mplayer.dcu 1-24-00

Yes, it records if a file name is provided when Open is called, but it only saves to a temporary file (ie, you can not write over the open file). If you assign a new filename before saving, the save is ok. However, you can not record a new wave file (which is of course what I want). Thus, this upgrade did NOT fix the problem.

According to the Windows SDK, the mciSendCommand requires a different structure when opening the Wave Audio device - it requires a parameter which specifies how many seconds to record.

tagMCI_OPEN_PARMSA = record dwCallback: DWORD; wDeviceID: MCIDEVICEID; lpstrDeviceType: PAnsiChar; lpstrElementName: PAnsiChar; lpstrAlias: PAnsiChar; end;

tagMCI_WAVE_OPEN_PARMSA = record dwCallback: DWORD; wDeviceID: MCIDEVICEID; lpstrDeviceType: PAnsiChar; lpstrElementName: PAnsiChar; lpstrAlias: PAnsiChar; dwBufferSeconds: DWORD; end;

The MPlayer unit (\Program Files\Borland\Delphi5\Source\Vcl\mplayer.pas) references the MMSystem unit (\Program Files\Borland\Delphi5\Source\Rtl\Win\mmsystem.pas) which encapsulates the Windows API (mmsystem.h -> winmm.dll).

Basic Windows API functions and related help (Help / Windows SDK)

PlaySound('C:\WINDOWS\MEDIA\Tada.wav', 0, SND_SYNC); // 0 is used because NULL caused a failure
sndPlaySound - maintained for backward compatibility
Recording Waveform Audio
mciSendCommand / mciSendString - used by MPlayer

Solution

Well, based on lots of reading, I now know why TMediaPlayer is unable to record a new Wave Audio File.

First, based on TI1427D, in order to create a new recording, both MCI_OPEN_ELEMENT and mci_Open_Type must be set when MCI_OPEN is called. However, MCI_OPEN_ELEMENT is set only when a file name is given.
Equally important, there is no way to set the recording parameters

Number of bits per sample - 8 or 16
Samples per second - 11K, 22k, 44k
Number of channels - 1 or 2 (mono or stereo)
In fact the MCI_SET command is only used twice in TMediaPlayer, and neither of those includes an MCI_WAVE_SET_PARMS structure.

Based on a search of the VCL source for "WaveFormat" and "WAVE_SET", none of the supplied Delphi components support wave recording.

References

Borland provides TI1427D which shows how to use MCI commands to record a new .wav file.
Playing and Recording Sound in Delphi, 1997 by Dr Darryl Gove. This is an excellent tutorial on using the Windows MultiMedia API functions (MMSystem). I highly recomend it.
Recording Wave Audio, Teach Yourself Borland Delphi 4 in 21 Days, Chapter 12, Graphics and Multimedia Programming
This reference confirms that there is no way for TMediaPlayer to create a new recording without first loading an existing wav file. It also points out that TMediaPlayer has no way to specify stereo/mono or samples per second.
Multimedia Components and Tools provides free components. There are audio recording components, but no source.
These Multimedia Tools are for sale ($500). I have not tried them nor do I recommend them, but you may find them interesting and they do offer some Free Stuff.
efg has tons of links, including one that explains how to record and play sounds using the Wave API (full source code written in C).
Torry provides numerous tips, including one to record wave files (*.wav).
Using WaveIn Functions to Record Sound is a tutorial on using WaveIn and WaveOut.

Playing Sounds

This works

uses mmsystem; // required for PlaySound

procedure TForm1.Button1Click(Sender: TObject);
begin
  PlaySound('C:\WINDOWS\Media\ding.wav', 0, 0);
end;

  PlaySound('C:\WINDOWS\Media\ding.wav', 0, SND_LOOP + SND_ASYNC); // loop forever

  PlaySound(nil, 0, 0); // stop the current sound

Torry provides numerous tips, including
- How to create and play a sine wave.

C++ Builder

This should have the same interface as Delphi, except that the syntax is different.

Windows API

See Waveform Audio and Waveform Audio Reference

  PlaySound("C:\\WINDOWS\\MEDIA\\Chord.wav", NULL, SND_SYNC);

See Recording Waveform Audio for information on the wavein commands. These let you set all the necessary parameters and supply buffers. This API looks useful when your final product is not a .wav file. (Use the MCI API for that.)

winmm.dll implements

   Specifically - mciSendCommand, sndPlaySound, PlaySound
   Generically  - mci, midi, joystick, mixer, waveIn, waveOut
                   and various related functions

References

The Sonic Spot describes the *.wav file format.

Author: Robert Clemenzi - clemenzi@cpcug.org

MultiMedia

Visual Basic 6.0

Delphi

Solution

References

Playing Sounds

C++ Builder

Windows API

References

URL: http:// cpcug.org / user / clemenzi / technical / Languages / MultiMedia.htm