Creating flac file or flac stream using BASS dll with Delphi

问题

I am playing with BASS from http://www.un4seen.com/.

I need to create a flac file(16bits) or flac stream from user speaking on Microphone.

I have seen this demo in BASS source code. There is a bassenc_flac.dll as well with these functions:

function BASS_Encode_FLAC_Start(handle:DWORD; options:PChar; flags:DWORD; proc:ENCODEPROCEX; user:Pointer): HENCODE; {$IFDEF MSWINDOWS}stdcall{$ELSE}cdecl{$ENDIF}; external bassencflacdll;
function BASS_Encode_FLAC_StartFile(handle:DWORD; options:PChar; flags:DWORD; filename:PChar): HENCODE; {$IFDEF MSWINDOWS}stdcall{$ELSE}cdecl{$ENDIF}; external bassencflacdll;

How could I change the next code to encode the audio to flac file or stream?

From RecordTest BASS demo

(* This is called while recording audio *)
function RecordingCallback(Handle: HRECORD; buffer: Pointer; length: DWORD; user: Pointer): boolean; stdcall;
var level:dword;
begin
    level:=BASS_ChannelGetLevel(Handle);
    // Copy new buffer contents to the memory buffer
    Form1.WaveStream.Write(buffer^, length);
    // Allow recording to continue
    Result := True;
end;

(* Start recording to memory *)
procedure TForm1.StartRecording;
begin
    if ComboBox1.ItemIndex < 0 then Exit;
    if WaveStream.Size > 0 then
    begin   // free old recording
        BASS_StreamFree(chan);
        WaveStream.Clear;
    end;
    // generate header for WAV file
    with WaveHdr do
    begin
        riff := 'RIFF';
        len := 36;
        cWavFmt := 'WAVEfmt ';
        dwHdrLen := 16;
        wFormat := 1;
        wNumChannels := 2;
        dwSampleRate := 44100;
        wBlockAlign := 4;
        dwBytesPerSec := 176400;
        wBitsPerSample := 16;
        cData := 'data';
        dwDataLen := 0;
    end;
    WaveStream.Write(WaveHdr, SizeOf(WAVHDR));
    // start recording @ 44100hz 16-bit stereo
    rchan := BASS_RecordStart(44100, 2, 0, @RecordingCallback, nil);
    if rchan = 0 then
    begin
        MessageDlg('Couldn''t start recording!', mtError, [mbOk], 0);
        WaveStream.Clear;
    end
    else
    begin
        bRecord.Caption := 'Stop';
        bPlay.Enabled := False;
        bSave.Enabled := False;
    end;
end;


(* Stop recording *)
procedure TForm1.StopRecording;
var
    i: integer;
  he:BassEnc.HENCODE;
begin
    BASS_ChannelStop(rchan);
    bRecord.Caption := 'Record';
    // complete the WAV header
    WaveStream.Position := 4;
    i := WaveStream.Size - 8;
    WaveStream.Write(i, 4);
    i := i - $24;
    WaveStream.Position := 40;
    WaveStream.Write(i, 4);
    WaveStream.Position := 0;
    // create a stream from the recorded data
    chan := BASS_StreamCreateFile(True, WaveStream.Memory, 0, WaveStream.Size, 0);
    if chan <> 0 then
    begin
        // enable "Play" & "Save" buttons
        bPlay.Enabled := True;
        bSave.Enabled := True;
    end
    else
        MessageDlg('Error creating stream from recorded data!', mtError, [mbOk], 0);
    if SaveDialog.Execute then
       WaveStream.SaveToFile(SaveDialog.FileName);

end;

回答1:

I have updated code because of comments that show incorrect work of previous encoder version. And I am totally agree with these comments.

In order to create an encoder to FLAC we should go to un4seen web-site and download the next files:

BASS audio library 2.4
BASSFLAC 2.4.4
BASSenc 2.4.14
BASSenc_FLAC 2.4.1.1

Go through these folders and look for the next files:

bass.pas
bassenc.pas
bassenc_flac.pas

Now place these pas-files into one folder and add it to Library via Delphi's options.
After this step create new project, save it in separate folder.
Then go through BASS_XXX folders and look for *.dll files.
Combine them together in the folder where you have saved your project!

Now let's write some code.

Add to the uses clause bass.pas, bassenc.pas and bassenc_flac.pas. Then copy the code shown below.

  uses ..., BASS, BASSEnc, BASSEnc_FLAC;

  ...

  TForm1 = class(TForm)
    ProgressBar1: TProgressBar;      
  public
    { Public declarations }
    procedure StartEncode(SourceFileName, OutputFileName: String);
    procedure StopEncode;
  end;

...

procedure TForm1.StartEncode(SourceFileName, OutputFileName: String);
var
  PercentDone: Cardinal;
  Buffer: array [0..1024] of Byte;
begin
  Channel := BASS_StreamCreateFile(false, PChar(SourceFileName), 0, 0, BASS_MUSIC_DECODE or BASS_UNICODE);
  BASSEnc_FLAC.BASS_Encode_FLAC_StartFile(Channel, 0, BASS_ENCODE_FP_AUTO or BASS_UNICODE, PChar(OutputFileName));
  while BASS_ChannelIsActive(Channel) > 0 do
  begin
    BASS_ChannelGetData(Channel, @Buffer, 1024);
    PercentDone := Trunc(100 * (BASS_ChannelGetPosition(Channel, BASS_POS_BYTE) / BASS_ChannelGetLength(Channel, BASS_POS_BYTE)));
    ProgressBar1.Position := PercentDone;
  end;
  StopEncode;
end;

procedure TForm1.StopEncode;
begin
  BASS_Encode_Stop(Channel);
  BASS_StreamFree(Channel);
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  BASS_Init(-1, 44100, 0, Application.Handle, nil);
  try   
    // Set name of file to convert it to FLAC and save it with output name
    StartEncode('SourceFileName', 'OutputFileName');
  finally
    BASS.BASS_Free;
  end;
end;

One notice:
Indeed, file encoded with previous version of the code had incorrect header (I could see it when opened file in Notepad.exe). After code has been updated I can see valid header (in Notepad, of course, because I have no professional instruments for work with audio-files).
Now you even have no need to add plugin to BASS as I did earlier. Since this I think that the encoder works as it was expected.

来源：https://stackoverflow.com/questions/52236347/creating-flac-file-or-flac-stream-using-bass-dll-with-delphi

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Delphi

audio

encode

flac

bass