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{* UltraStar Deluxe - Karaoke Game
*
* UltraStar Deluxe is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*}
unit UAudioConverter_SDL;
interface
{$IFDEF FPC}
{$MODE Delphi}
{$ENDIF}
{$I switches.inc}
uses
UMusic,
ULog,
UMediaPlugin,
UMediaCore_SDL,
sdl,
SysUtils,
Math;
type
TAudioConverter_SDL = class(TInterfacedObject, IAudioConverter)
public
function GetName(): string;
function GetPriority(): integer;
function Init(): boolean;
function Finalize(): boolean;
function Open(SrcFormatInfo: TAudioFormatInfo;
DstFormatInfo: TAudioFormatInfo): TAudioConvertStream;
end;
TAudioConvertStream_SDL = class(TAudioConvertStream)
private
cvt: TSDL_AudioCVT;
function Init(): boolean;
protected
constructor Create(SrcFormatInfo: TAudioFormatInfo;
DstFormatInfo: TAudioFormatInfo);
public
destructor Destroy(); override;
class function Open(SrcFormatInfo: TAudioFormatInfo;
DstFormatInfo: TAudioFormatInfo): TAudioConvertStream_SDL;
function Convert(InputBuffer: PByteArray; OutputBuffer: PByteArray; var InputSize: integer): integer; override;
function GetOutputBufferSize(InputSize: integer): integer; override;
function GetRatio(): double; override;
end;
implementation
{ TAudioConverter_SDL }
function TAudioConverter_SDL.GetName(): string;
begin
Result := 'AudioConverter_SDL';
end;
function TAudioConverter_SDL.GetPriority(): integer;
begin
{* Notes:
* - 44.1kHz to 48kHz conversion or vice versa is not supported
* by SDL 1.2 (will be introduced in 1.3).
* No conversion takes place in this cases.
* This is because SDL just converts differences in powers of 2.
* So the result might not be that accurate.
* This IS audible (voice to high/low) and it needs good synchronization
* with the video or the lyrics timer.
* - float<->int16 conversion is not supported (will be part of 1.3) and
* SDL (<1.3) is not capable of handling floats at all.
* -> Using FFmpeg or libsamplerate for resampling is preferred.
* Use SDL for channel and format conversion only.
*}
Result := 0;
end;
function TAudioConverter_SDL.Init(): boolean;
begin
Result := true;
end;
function TAudioConverter_SDL.Finalize(): boolean;
begin
Result := true;
end;
function TAudioConverter_SDL.Open(SrcFormatInfo: TAudioFormatInfo;
DstFormatInfo: TAudioFormatInfo): TAudioConvertStream;
begin
Result := TAudioConvertStream_SDL.Open(SrcFormatInfo, DstFormatInfo);
end;
{ TAudioConvertStream_SDL }
constructor TAudioConvertStream_SDL.Create(SrcFormatInfo: TAudioFormatInfo;
DstFormatInfo: TAudioFormatInfo);
begin
inherited Create(SrcFormatInfo, DstFormatInfo);
end;
destructor TAudioConvertStream_SDL.Destroy();
begin
inherited;
end;
class function TAudioConvertStream_SDL.Open(SrcFormatInfo: TAudioFormatInfo;
DstFormatInfo: TAudioFormatInfo): TAudioConvertStream_SDL;
var
Stream: TAudioConvertStream_SDL;
begin
Result := nil;
Stream := TAudioConvertStream_SDL.Create(SrcFormatInfo, DstFormatInfo);
if (not Stream.Init()) then
begin
Stream.Free;
Exit;
end;
Result := Stream;
end;
function TAudioConvertStream_SDL.Init(): boolean;
var
srcFormat: UInt16;
dstFormat: UInt16;
begin
Result := false;
if (not ConvertAudioFormatToSDL(srcFormatInfo.Format, srcFormat) or
not ConvertAudioFormatToSDL(dstFormatInfo.Format, dstFormat)) then
begin
Log.LogError('Audio-format not supported by SDL', 'TSoftMixerPlaybackStream.InitFormatConversion');
Exit;
end;
if (SDL_BuildAudioCVT(@cvt,
srcFormat, srcFormatInfo.Channels, Round(srcFormatInfo.SampleRate),
dstFormat, dstFormatInfo.Channels, Round(dstFormatInfo.SampleRate)) = -1) then
begin
Log.LogError(SDL_GetError(), 'TSoftMixerPlaybackStream.InitFormatConversion');
Exit;
end;
Result := true;
end;
(*
* Returns the size of the output buffer. This might be bigger than the actual
* size of resampled audio data.
*)
function TAudioConvertStream_SDL.GetOutputBufferSize(InputSize: integer): integer;
begin
// Note: len_ratio must not be used here. Even if the len_ratio is 1.0, len_mult might be 2.
// Example: 44.1kHz/mono to 22.05kHz/stereo -> len_ratio=1, len_mult=2
Result := InputSize * cvt.len_mult;
end;
function TAudioConvertStream_SDL.GetRatio(): double;
begin
Result := cvt.len_ratio;
end;
function TAudioConvertStream_SDL.Convert(InputBuffer: PByteArray; OutputBuffer: PByteArray; var InputSize: integer): integer;
begin
Result := -1;
if (InputSize <= 0) then
begin
// avoid div-by-zero problems
if (InputSize = 0) then
Result := 0;
Exit;
end;
// OutputBuffer is always bigger than or equal to InputBuffer
Move(InputBuffer[0], OutputBuffer[0], InputSize);
cvt.buf := PUint8(OutputBuffer);
cvt.len := InputSize;
if (SDL_ConvertAudio(@cvt) = -1) then
Exit;
Result := cvt.len_cvt;
end;
initialization
MediaManager.add(TAudioConverter_SDL.Create);
end.
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