Mercurial > sdl-ios-xcode
view src/audio/mme/SDL_mmeaudio.c @ 773:da0a2ad35bf4
Date: Sun, 4 Jan 2004 23:48:19 +0100
From: Max Horn
Subject: Re: Again Audio CD patch
Am 04.01.2004 um 22:38 schrieb Sam Lantinga:
>
> Okay, I fixed the buffering problems by simply using a 4 second buffer
> instead of a 1 second buffer. However, using your code I can't play an
> entire CD - the playback stops after the first song.
>
Found the problem: FSReadFork returns eofErr when the file is finished.
However, we check its return value for errors, and if anything but
noErr occurs, the reader thread aborts its current iteration. That is
bad, because it aborts before it can ever set the flag which tells that
the file is over (also, any remaining data which FSRead did return is
lost - so you'd not hear about to 4 seconds from the end of the file.
Furthermore, the computed data size was 8 bytes to high (I forgot to
account for the fact that the size of an (A)IFF chunk always contains
the chunk header & size fields, too). This is enough to make it work.
However, the end condition is rather fragile, so I tuned some other
things to be pessimistic (check for <= 0 instead of == 0, when eofErr
is encountered enforce mReadFilePosition == mFileLength). You never
know...
The attached patch fixes the issue for me.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Mon, 05 Jan 2004 00:57:51 +0000 |
parents | b8d311d90021 |
children | 3692456e7b0f |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997-2004 Sam Lantinga This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library 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 Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with this library; if not, write to the Free Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA Sam Lantinga slouken@libsdl.org */ /* Tru64 UNIX MME support */ #include "SDL_mmeaudio.h" static BOOL inUse[NUM_BUFFERS]; /* Audio driver functions */ static int MME_OpenAudio(_THIS, SDL_AudioSpec *spec); static void MME_WaitAudio(_THIS); static Uint8 *MME_GetAudioBuf(_THIS); static void MME_PlayAudio(_THIS); static void MME_WaitDone(_THIS); static void MME_CloseAudio(_THIS); /* Audio driver bootstrap functions */ static int Audio_Available(void) { return(1); } static void Audio_DeleteDevice(SDL_AudioDevice *device) { if ( device ) { if ( device->hidden ) { free(device->hidden); device->hidden = NULL; } free(device); device = NULL; } } static SDL_AudioDevice *Audio_CreateDevice(int devindex) { SDL_AudioDevice *this; /* Initialize all variables that we clean on shutdown */ this = malloc(sizeof(SDL_AudioDevice)); if ( this ) { memset(this, 0, (sizeof *this)); this->hidden = malloc((sizeof *this->hidden)); } if ( (this == NULL) || (this->hidden == NULL) ) { SDL_OutOfMemory(); if ( this ) { free(this); } return(0); } memset(this->hidden, 0, (sizeof *this->hidden)); /* Set the function pointers */ this->OpenAudio = MME_OpenAudio; this->WaitAudio = MME_WaitAudio; this->PlayAudio = MME_PlayAudio; this->GetAudioBuf = MME_GetAudioBuf; this->WaitDone = MME_WaitDone; this->CloseAudio = MME_CloseAudio; this->free = Audio_DeleteDevice; return this; } AudioBootStrap MMEAUDIO_bootstrap = { "waveout", "Tru64 MME WaveOut", Audio_Available, Audio_CreateDevice }; static void SetMMerror(char *function, MMRESULT code) { int len; char errbuf[MAXERRORLENGTH]; sprintf(errbuf, "%s: ", function); len = strlen(errbuf); waveOutGetErrorText(code, errbuf+len, MAXERRORLENGTH-len); SDL_SetError("%s",errbuf); } static void CALLBACK MME_CALLBACK(HWAVEOUT hwo, UINT uMsg, DWORD dwInstance, LPARAM dwParam1, LPARAM dwParam2) { WAVEHDR *wp = (WAVEHDR *) dwParam1; if ( uMsg == WOM_DONE ) inUse[wp->dwUser] = FALSE; } static int MME_OpenAudio(_THIS, SDL_AudioSpec *spec) { MMRESULT result; int i; mixbuf = NULL; /* Set basic WAVE format parameters */ shm = mmeAllocMem(sizeof(*shm)); if ( shm == NULL ) { SDL_SetError("Out of memory: shm"); return(-1); } shm->sound = 0; shm->wFmt.wf.wFormatTag = WAVE_FORMAT_PCM; /* Determine the audio parameters from the AudioSpec */ switch ( spec->format & 0xFF ) { case 8: /* Unsigned 8 bit audio data */ spec->format = AUDIO_U8; shm->wFmt.wBitsPerSample = 8; break; case 16: /* Signed 16 bit audio data */ spec->format = AUDIO_S16; shm->wFmt.wBitsPerSample = 16; break; default: SDL_SetError("Unsupported audio format"); return(-1); } shm->wFmt.wf.nChannels = spec->channels; shm->wFmt.wf.nSamplesPerSec = spec->freq; shm->wFmt.wf.nBlockAlign = shm->wFmt.wf.nChannels * shm->wFmt.wBitsPerSample / 8; shm->wFmt.wf.nAvgBytesPerSec = shm->wFmt.wf.nSamplesPerSec * shm->wFmt.wf.nBlockAlign; /* Check the buffer size -- minimum of 1/4 second (word aligned) */ if ( spec->samples < (spec->freq/4) ) spec->samples = ((spec->freq/4)+3)&~3; /* Update the fragment size as size in bytes */ SDL_CalculateAudioSpec(spec); /* Open the audio device */ result = waveOutOpen(&(shm->sound), WAVE_MAPPER, &(shm->wFmt.wf), MME_CALLBACK, NULL, (CALLBACK_FUNCTION|WAVE_OPEN_SHAREABLE)); if ( result != MMSYSERR_NOERROR ) { SetMMerror("waveOutOpen()", result); return(-1); } /* Create the sound buffers */ mixbuf = (Uint8 *)mmeAllocBuffer(NUM_BUFFERS * (spec->size)); if ( mixbuf == NULL ) { SDL_SetError("Out of memory: mixbuf"); return(-1); } for (i = 0; i < NUM_BUFFERS; i++) { shm->wHdr[i].lpData = &mixbuf[i * (spec->size)]; shm->wHdr[i].dwBufferLength = spec->size; shm->wHdr[i].dwFlags = 0; shm->wHdr[i].dwUser = i; shm->wHdr[i].dwLoops = 0; /* loop control counter */ shm->wHdr[i].lpNext = NULL; /* reserved for driver */ shm->wHdr[i].reserved = 0; inUse[i] = FALSE; } next_buffer = 0; return 0; } static void MME_WaitAudio(_THIS) { while ( inUse[next_buffer] ) { mmeWaitForCallbacks(); mmeProcessCallbacks(); } } static Uint8 *MME_GetAudioBuf(_THIS) { Uint8 *retval; inUse[next_buffer] = TRUE; retval = (Uint8 *)(shm->wHdr[next_buffer].lpData); return retval; } static void MME_PlayAudio(_THIS) { /* Queue it up */ waveOutWrite(shm->sound, &(shm->wHdr[next_buffer]), sizeof(WAVEHDR)); next_buffer = (next_buffer+1)%NUM_BUFFERS; } static void MME_WaitDone(_THIS) { MMRESULT result; int i; if ( shm->sound ) { for (i = 0; i < NUM_BUFFERS; i++) while ( inUse[i] ) { mmeWaitForCallbacks(); mmeProcessCallbacks(); } result = waveOutReset(shm->sound); if ( result != MMSYSERR_NOERROR ) SetMMerror("waveOutReset()", result); mmeProcessCallbacks(); } } static void MME_CloseAudio(_THIS) { MMRESULT result; if ( mixbuf ) { result = mmeFreeBuffer(mixbuf); if (result != MMSYSERR_NOERROR ) SetMMerror("mmeFreeBuffer", result); mixbuf = NULL; } if ( shm ) { if ( shm->sound ) { result = waveOutClose(shm->sound); if (result != MMSYSERR_NOERROR ) SetMMerror("waveOutClose()", result); mmeProcessCallbacks(); } result = mmeFreeMem(shm); if (result != MMSYSERR_NOERROR ) SetMMerror("mmeFreeMem()", result); shm = NULL; } }