VB6 RC5-CoreAudio-Demo

Here a small CoreAudio-Example, based on the appropriate abstraction-Classes of the RichClient.
(as mentioned and requested in this thread): http://www.vbforums.com/showthread.p...ther-like-Game

CoreAudio was introduced as the new (LowLevel) SoundAPI for Win-Versions from Vista onwards.

It allows such things as "InApp-Session-VolumeControl, Soundbuffer-reading and -writing, Enumeration of
Sound-Devices, Fine-Control over each of the channels of e.g. a "5+1" SoundCard etc...

The Read-direction of CoreAudio-SoundBuffers I've already covered in this older example here:
http://www.vbforums.com/showthread.p...and-onwards%29
(visualizing the Buffer-Input, which comes in over: ...GetDefaultAudioEndpoint(eCapture, eCommunications) -> usually the microphone).

This example here is focusing on demonstrating the handling of "InApp-SoundVolume/Muting" -
and the SoundRendering of 4 smaller SoundBuffers (which reside as *.mp3 in the Apps \Res\-SubFolder).
Here the Zip: Attachment 138073

With relatively low efforts, one could expand on this Demo, to e.g. implement a nice
"Piano-Roll-like Sequencer" - or something alike (as seen in some Phone- or -Tablet-Apps, that cover
simple "SoundLoop-Pattern-Mixers" which support live-changes of "correctly fitted" Sample-Loops).

Here's a ScreenShot, what the Demo currently looks like:
http://vbRichClient.com/Downloads/CoreAudioDemo1.png

The 4 SoundSample-Player-Widgets to the right of the above Form can be:
- in case of the Top-Widget, labelled 'SampleLoop' - switched On and Off permanently
- and the lower three Sound-Widgets are in "Tap-Mode" (acting more like a little Drum-Kit)

So you can Switch-On the TopMost Sound - it will be in repeat-mode by default -
and then you can add sound by "tapping" the other three (if you keep the Mouse down,
the 3 Tap-Widgets will repeat themselves in a timely fashion).

So, whilst the right part of the above ScreenShot demonstrates the CoreAudio-SoundBuffer-Handling,
the left part of the Screen (the rotating Knob-Widget) demonstrates the interaction with:
- cSimpleAudioVolume (responsible for interaction with the InApp-SoundLevel and InApp-Muting)
- cAudioMeterInformation (responsible for the Peak-Meter-Visualization at the bottom of the Knob).

This InApp-AudioVolume-Handling works in a "two-way-fashion", since it is also present in
the new WinSystem-Mixer-Dialogues:
http://vbRichClient.com/Downloads/CoreAudioDemo3.png

In the above ScreenShot, the focused Entry labeled "CoreAudioDemo" allows to
control your InApp-SoundVolume/Muting as well - and should be properly reflected
in the appropriate Control of your App, so that both GUI-interactions remain "synced"
(the Knob reflecting the Settings of the System-Dialogue, and vice versa).

http://vbRichClient.com/Downloads/CoreAudioDemo2.png

The cSimpleAudioVolume-Class of the RC5 offers the needed Events for that kind of
two-way interaction.

But take a look at the code yourself, play around a bit - and just ask when something is not clear.

Have fun!

Olaf

Much appreciated, Olaf. Checking it out now...

Is there a way to control the other app volumes, rather than just the current app ? I've had a look but can fathom it out or see any documentation.thank you.

When I tested the RC5-CoreAudio-Demo on Win10, everything was OK. But when I tested it on XP, there was an error message: Couldn't create DeviceEnumerator

CoreAudio is only available on Vista and upwards...

Quote:

---

Originally Posted by ColinE66

CoreAudio is only available on Vista and upwards...

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Oh, thank you for your reminder. I was so blind that I didn't see Olaf's instructions.

Hi Olaf,

I tried to open a large mp3 file (8M) in the example of "VB6 RC5-CoreAudio-Demo", the program popped up an error message: Run-time error '6': Overflow

Code:

---


Public Property Get FrameIdxCurrent() As Double
  If ARC Is Nothing Then Exit Property
  FrameIdxCurrent = (FrameIdxToCopyFrom - ARC.CalcFrameCountAheadOfClientSrc + 1000 * 1# * FramesTotal) Mod FramesTotal
End Property

---

Note: FramesTotal = 21703680 at this point.

I don't quite understand the meaning of that red sentence (code line with error), I made some changes to avoid Overflow error. The program now opens a large Mp3 file without error. Maybe someone else has a better solution.

Code:

---


Public Property Get FrameIdxCurrent() As Double
    If ARC Is Nothing Then Exit Property
 
    '---------------------------------------------------------------------------------------------------------------------------------------------
    '--- To avoid overflow --- DreamManor Update on 24-11-2017 ---
    'FrameIdxCurrent = (FrameIdxToCopyFrom - ARC.CalcFrameCountAheadOfClientSrc + 1000 * 1# * FramesTotal) Mod FramesTotal
 
    Dim nIndex As Double
       
    nIndex = 1# * 1000 * FramesTotal
    nIndex = FrameIdxToCopyFrom - ARC.CalcFrameCountAheadOfClientSrc + nIndex
   
    If nIndex <= 2 ^ 31 - 1 Then
        FrameIdxCurrent = (FrameIdxToCopyFrom - ARC.CalcFrameCountAheadOfClientSrc + 1000 * FramesTotal) Mod FramesTotal
    Else
        nIndex = nIndex / FramesTotal
        nIndex = nIndex - Int(nIndex)
        If nIndex > 0 Then
            nIndex = nIndex * FramesTotal
        End If
        FrameIdxCurrent = nIndex
    End If
    '--------------------------------------------------------------------------------------------------------------------------------------------
   
End Property

---

Now there is another problem that needs Olaf's help.
When I open an mp3 file(1.5M), the following error message appears:

Code:

---

Public Sub InitFromMP3(FileNameOrByteArray, RenderEndPoint As cMMDevice, ByVal PlayFreq As Long, Optional ByVal SkipLeadingSilence As Boolean)
Dim Src() As Byte, Dst() As Long, DstBytesUsed As Long, msEstimated As Long
    Src = FileNameOrByteArray
    If VarType(FileNameOrByteArray) = vbString Then Src = New_c.FSO.ReadByteContent(CStr(FileNameOrByteArray))
    With New_c.MP3Resource
      .GetMP3Info Src, OrigFreq, Channels, ID3Offs, msEstimated
      ReDim Dst(0 To msEstimated / 1000 * OrigFreq * 1.5)
      .OpenConverter OrigFreq, Channels, 16
      .ConvertBuffer VarPtr(Src(ID3Offs)), UBound(Src) + 1 - ID3Offs, VarPtr(Dst(0)), 4 * (UBound(Dst) + 1), DstBytesUsed, True
    End With
    ReDim Preserve Dst(DstBytesUsed \ 4 - 1)
    InitWithFrames Dst, RenderEndPoint, PlayFreq, SkipLeadingSilence
End Sub

---

Then you need to figure out what's needed in the following code line:

Code:

---

ReDim Dst(0 To msEstimated / 1000 * OrigFreq * 1.5)

---

Is the file compressed using VBR or a fixed bitrate?

Quote:

---

Originally Posted by Arnoutdv

Then you need to figure out what's needed in the following code line:

Code:

---

ReDim Dst(0 To msEstimated / 1000 * OrigFreq * 1.5)

---

Is the file compressed using VBR or a fixed bitrate?

---

Hi Arnoutdv, thanks for your reminder.

I tracked the variable msEstimated, whose value is 38353 ms, but in TheTrick's software this value (duration-ms) is 39079 ms. This value is also greater than 39,000 in Audacity software. In other words, in the RC5.MP3Resource class, the audio files' playback time (estimated time) is less than other software. This causes the allocation capacity of the dst array is too small. I modified the following source code, now the program can play that mp3 file:

Code:

---

'ReDim Dst(0 To msEstimated / 1000 * OrigFreq * 1.5)
ReDim Dst(0 To msEstimated / 1000 * OrigFreq * 3)

---

I don't know what is the basis of multiplying 1.5 or multiplying 3 in the source code?

In addition, vbForums doesn't allow uploading files over 500K, so I have no way to upload the test file.

As soon as I start the project "CoreAudioDemo", I get this error:

Ungültiger Prozeduraufruf oder ungültiges Argument.
(Invalid procedure call or invalid argument)

Windows 10:

Attachment 183478

Quote:

---

Originally Posted by tmighty2

As soon as I start the project "CoreAudioDemo", I get this error:

Ungültiger Prozeduraufruf oder ungültiges Argument.
(Invalid procedure call or invalid argument)

---

Are you trying to use that (RC5-based) demo with RC6 by any chance?

If yes, then "just switching the Project-Reference" is not enough for most older Demos.

In many larger RC5-Demos, there's an additional need, to do a global search/replace on the Code:
- searching for fully qualified Class-Types, which start with the term: [vbRichClient5.] <-- please notice the trailing dot ...
- replacing it with either an empty String, or with a leading [RC6.] as the lib-name of the fully qualified Class-Type

Olaf

Excellent work Olaf. It's also a great example of Cairo widgets.

I feel like Sherlock Holmes researching RichClient, and a very pleasant discovery was the Unicode path function to supersede VB's anemic ANSI Dir function, or the various DirW routines floating around.

Code:

---

Dim DL As cDirList
Set DL = New_c.FSO.GetDirList(App.Path & "\Res", , "*.jpg;*.png")

---

I see there is a cMP3Resource class in RC5 and RC6 with :

Code:

---

Function OpenConverter(DstFreq As Long, [DstChan As Long = 2], [DstBits As Long = 16], [DstFmtT As Long = 1]) As Boolean

---

I assume this for conversion to .Wav ...? Are there any examples of how to use this?

It would be overkill for converting an mp3 to DstBits As Long = 24, or 32 ---- but if it works, that would be nice for some audio editing software to do granular noise reduction.

Cheers

Quote:

---

Originally Posted by taishan

I see there is a cMP3Resource class in RC5 and RC6 with :

Code:

---

Function OpenConverter(DstFreq As Long, [DstChan As Long = 2], [DstBits As Long = 16], [DstFmtT As Long = 1]) As Boolean

---

I assume this for conversion to .Wav ...? Are there any examples of how to use this?

---

If I use google to find RC-Demos for a certain class...
- I usually include the classname in DoubleQuotes
- and prefix this search-term with site:vbForums.com

E.g. in your case, it would look like: [ site:vbforums.com "cMP3Resource" ]
Which spits out (among a handful of other related Links):
https://www.vbforums.com/showthread....=1#post4936139

Olaf

Quote:

---

Originally Posted by Schmidt

If I use google to find RC-Demos for a certain class...
- I usually include the classname in DoubleQuotes
- and prefix this search-term with site:vbForums.com

E.g. in your case, it would look like: [ site:vbforums.com "cMP3Resource" ]
Which spits out (among a handful of other related Links):
https://www.vbforums.com/showthread....=1#post4936139

Olaf

---

Thank you for the google search hints! you are the man!

btw, please don't let this documentation expire. Seems like a few examples worth keeping... plus, it is a cool website. Cheers