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authork-m_schindler <k-m_schindler@b956fd51-792f-4845-bead-9b4dfca2ff2c>2008-08-27 15:00:10 +0000
committerk-m_schindler <k-m_schindler@b956fd51-792f-4845-bead-9b4dfca2ff2c>2008-08-27 15:00:10 +0000
commit9506a3ab6ae1b5c51eec2ccb8773eb4219766e7d (patch)
treeb65ae0f889de664651dddabee852908f191eac07 /src/classes/UAudioCore_Portaudio.pas
parent16a6e6801fde495b2782e2e04a0cf055ce1e1516 (diff)
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rename Classes part2
git-svn-id: svn://svn.code.sf.net/p/ultrastardx/svn/trunk@1308 b956fd51-792f-4845-bead-9b4dfca2ff2c
Diffstat (limited to 'src/classes/UAudioCore_Portaudio.pas')
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diff --git a/src/classes/UAudioCore_Portaudio.pas b/src/classes/UAudioCore_Portaudio.pas
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+unit UAudioCore_Portaudio;
+
+interface
+
+{$IFDEF FPC}
+ {$MODE Delphi}
+{$ENDIF}
+
+{$I ../switches.inc}
+
+
+uses
+ Classes,
+ SysUtils,
+ portaudio;
+
+type
+ TAudioCore_Portaudio = class
+ public
+ constructor Create();
+ class function GetInstance(): TAudioCore_Portaudio;
+ function GetPreferredApiIndex(): TPaHostApiIndex;
+ function TestDevice(inParams, outParams: PPaStreamParameters; var sampleRate: Double): boolean;
+ end;
+
+implementation
+
+uses
+ ULog;
+
+{*
+ * The default API used by Portaudio is the least common denominator
+ * and might lack efficiency. In addition it might not even work.
+ * We use an array named ApiPreferenceOrder with which we define the order of
+ * preferred APIs to use. The first API-type in the list is tried first.
+ * If it is not available the next one is tried and so on ...
+ * If none of the preferred APIs was found the default API (detected by
+ * portaudio) is used.
+ *
+ * Pascal does not permit zero-length static arrays, so you must use paDefaultApi
+ * as an array's only member if you do not have any preferences.
+ * You can also append paDefaultApi to a non-zero length preferences array but
+ * this is optional because the default API is always used as a fallback.
+ *}
+const
+ paDefaultApi = -1;
+const
+ ApiPreferenceOrder:
+{$IF Defined(MSWINDOWS)}
+ // Note1: Portmixer has no mixer support for paASIO and paWASAPI at the moment
+ // Note2: Windows Default-API is MME, but DirectSound is faster
+ array[0..0] of TPaHostApiTypeId = ( paDirectSound );
+{$ELSEIF Defined(LINUX)}
+ // Note: Portmixer has no mixer support for JACK at the moment
+ array[0..2] of TPaHostApiTypeId = ( paALSA, paJACK, paOSS );
+{$ELSEIF Defined(DARWIN)}
+ array[0..0] of TPaHostApiTypeId = ( paDefaultApi ); // paCoreAudio
+{$ELSE}
+ array[0..0] of TPaHostApiTypeId = ( paDefaultApi );
+{$IFEND}
+
+
+{ TAudioInput_Portaudio }
+
+var
+ Instance: TAudioCore_Portaudio;
+
+constructor TAudioCore_Portaudio.Create();
+begin
+ inherited;
+end;
+
+class function TAudioCore_Portaudio.GetInstance(): TAudioCore_Portaudio;
+begin
+ if not assigned(Instance) then
+ Instance := TAudioCore_Portaudio.Create();
+ Result := Instance;
+end;
+
+function TAudioCore_Portaudio.GetPreferredApiIndex(): TPaHostApiIndex;
+var
+ i: integer;
+ apiIndex: TPaHostApiIndex;
+ apiInfo: PPaHostApiInfo;
+begin
+ result := -1;
+
+ // select preferred sound-API
+ for i:= 0 to High(ApiPreferenceOrder) do
+ begin
+ if(ApiPreferenceOrder[i] <> paDefaultApi) then
+ begin
+ // check if API is available
+ apiIndex := Pa_HostApiTypeIdToHostApiIndex(ApiPreferenceOrder[i]);
+ if(apiIndex >= 0) then
+ begin
+ // we found an API but we must check if it works
+ // (on linux portaudio might detect OSS but does not provide
+ // any devices if ALSA is enabled)
+ apiInfo := Pa_GetHostApiInfo(apiIndex);
+ if (apiInfo^.deviceCount > 0) then
+ begin
+ Result := apiIndex;
+ break;
+ end;
+ end;
+ end;
+ end;
+
+ // None of the preferred APIs is available -> use default
+ if(result < 0) then
+ begin
+ result := Pa_GetDefaultHostApi();
+ end;
+end;
+
+{*
+ * Portaudio test callback used by TestDevice().
+ *}
+function TestCallback(input: Pointer; output: Pointer; frameCount: Longword;
+ timeInfo: PPaStreamCallbackTimeInfo; statusFlags: TPaStreamCallbackFlags;
+ inputDevice: Pointer): Integer; cdecl;
+begin
+ // this callback is called only once
+ result := paAbort;
+end;
+
+(*
+ * Tests if the callback works. Some devices can be opened without
+ * an error but the callback is never called. Calling Pa_StopStream() on such
+ * a stream freezes USDX then. Probably because the callback-thread is deadlocked
+ * due to some bug in portaudio. The blocking Pa_ReadStream() and Pa_WriteStream()
+ * block forever too and though can't be used for testing.
+ *
+ * To avoid freezing Pa_AbortStream (or Pa_CloseStream which calls Pa_AbortStream)
+ * can be used to force the stream to stop. But for some reason this stops debugging
+ * in gdb with a "no process found" message.
+ *
+ * Because freezing devices are non-working devices we test the devices here to
+ * be able to exclude them from the device-selection list.
+ *
+ * Portaudio does not provide any test to check this error case (probably because
+ * it should not even occur). So we have to open the device, start the stream and
+ * check if the callback is called (the stream is stopped if the callback is called
+ * for the first time, so we can poll until the stream is stopped).
+ *
+ * Another error that occurs is that some devices (even the default device) might
+ * work at the beginning but stop after a few calls (maybe 50) of the callback.
+ * For me this problem occurs with the default output-device. The "dmix" or "front"
+ * device must be selected instead. Another problem is that (due to a bug in
+ * portaudio or ALSA) the "front" device is not detected every time portaudio
+ * is started. Sometimes it needs two or more restarts.
+ *
+ * There is no reasonable way to test for these errors. For the first error-case
+ * we could test if the callback is called 50 times but this can take a second
+ * for each device and it can fail in the 51st or even 100th callback call then.
+ *
+ * The second error-case cannot be tested at all. How should we now that one
+ * device is missing if portaudio is not even able to detect it.
+ * We could start and terminate Portaudio for several times and see if the device
+ * count changes but this is ugly.
+ *
+ * Conclusion: We are not able to autodetect a working device with
+ * portaudio (at least not with the newest v19_20071207) at the moment.
+ * So we have to provide the possibility to manually select an output device
+ * in the UltraStar options if we want to use portaudio instead of SDL.
+ *)
+function TAudioCore_Portaudio.TestDevice(inParams, outParams: PPaStreamParameters; var sampleRate: Double): boolean;
+var
+ stream: PPaStream;
+ err: TPaError;
+ cbWorks: boolean;
+ cbPolls: integer;
+ i: integer;
+const
+ altSampleRates: array[0..1] of Double = (44100, 48000); // alternative sample-rates
+begin
+ Result := false;
+
+ if (sampleRate <= 0) then
+ sampleRate := 44100;
+
+ // check if device supports our input-format
+ err := Pa_IsFormatSupported(inParams, outParams, sampleRate);
+ if(err <> paNoError) then
+ begin
+ // we cannot fix the error -> exit
+ if (err <> paInvalidSampleRate) then
+ Exit;
+
+ // try alternative sample-rates to the detected one
+ sampleRate := 0;
+ for i := 0 to High(altSampleRates) do
+ begin
+ // do not check the detected sample-rate twice
+ if (altSampleRates[i] = sampleRate) then
+ continue;
+ // check alternative
+ err := Pa_IsFormatSupported(inParams, outParams, altSampleRates[i]);
+ if (err = paNoError) then
+ begin
+ // sample-rate works
+ sampleRate := altSampleRates[i];
+ break;
+ end;
+ end;
+ // no working sample-rate found
+ if (sampleRate = 0) then
+ Exit;
+ end;
+
+ // FIXME: for some reason gdb stops after a call of Pa_AbortStream()
+ // which is implicitely called by Pa_CloseStream().
+ // gdb's stops with the message: "ptrace: no process found".
+ // Probably because the callback-thread is killed what confuses gdb.
+ {$IF Defined(Debug) and Defined(Linux)}
+ cbWorks := true;
+ {$ELSE}
+ // open device for testing
+ err := Pa_OpenStream(stream, inParams, outParams, sampleRate,
+ paFramesPerBufferUnspecified,
+ paNoFlag, @TestCallback, nil);
+ if(err <> paNoError) then
+ begin
+ exit;
+ end;
+
+ // start the callback
+ err := Pa_StartStream(stream);
+ if(err <> paNoError) then
+ begin
+ Pa_CloseStream(stream);
+ exit;
+ end;
+
+ cbWorks := false;
+ // check if the callback was called (poll for max. 200ms)
+ for cbPolls := 1 to 20 do
+ begin
+ // if the test-callback was called it should be aborted now
+ if (Pa_IsStreamActive(stream) = 0) then
+ begin
+ cbWorks := true;
+ break;
+ end;
+ // not yet aborted, wait and try (poll) again
+ Pa_Sleep(10);
+ end;
+
+ // finally abort the stream
+ Pa_CloseStream(stream);
+ {$IFEND}
+
+ Result := cbWorks;
+end;
+
+end.