Some basic, unstable, unoptimized MP3 support.

icculus · Apr 8, 2005 · ea4fbae · ea4fbae
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diff --git a/osx/AL_EXT_mp3/al_ext_mp3.c b/osx/AL_EXT_mp3/al_ext_mp3.c
@@ -0,0 +1,197 @@
+/**
+ * OpenAL cross platform audio library
+ * Copyright (C) 1999-2000 by authors.
+ * 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 Software Foundation, Inc., 59 Temple Place - Suite 330,
+ *  Boston, MA  02111-1307, USA.
+ * Or go to http://www.gnu.org/copyleft/lgpl.html
+ */
+
+// This is crappy MP3 support from mpglib.
+//  mpglib is also LGPL'd.
+//  mpglib doesn't really tolerate data corruption.
+
+#if !SUPPORTS_AL_EXT_MP3
+#error You should not compile this without SUPPORTS_AL_EXT_MP3 defined.
+#endif
+
+#include "alInternal.h"
+#include "mpg123_sdlsound.h"
+#include "mpglib_sdlsound.h"
+
+#if HAVE_PRAGMA_EXPORT
+#pragma export off
+#endif
+
+typedef struct
+{
+    struct mpstr mp;
+    UInt8 outbuf[8192];
+    int outleft;
+    int outpos;
+} MP3Opaque;
+
+
+static int doMp3Decode(MP3Opaque *o, void *outbuf, ALsizei outsize)
+{
+    int bw = 0;
+
+    while (bw < outsize)
+    {
+        if (o->outleft > 0)
+        {
+            ALsizei cpysize = outsize - bw;
+            if (cpysize > o->outleft)
+                cpysize = o->outleft;
+            memcpy(((UInt8 *) outbuf) + bw, o->outbuf + o->outpos, cpysize);
+            bw += cpysize;
+            o->outpos += cpysize;
+            o->outleft -= cpysize;
+            continue;
+        } // if
+
+        // need to decode more from the MP3 stream...
+        o->outleft = o->outpos = 0;
+        decodeMP3(&o->mp, NULL, 0, o->outbuf,
+                  sizeof (o->outbuf), &o->outleft);
+        if (o->outleft == 0)
+            break;
+    } // while
+
+    return(bw / (sizeof (SInt16) * 2));
+} // doMp3Decode
+
+
+static UInt32 __alMixMP3(struct ALcontext_struct *ctx, struct ALbuffer_struct *buf,
+                     struct ALsource_struct *src, Float32 *_dst, UInt32 frames)
+{
+    register UInt32 channels = ctx->device->streamFormat.mChannelsPerFrame;
+    register MP3Opaque *opaque = (MP3Opaque *) src->opaque;
+    register int samples = frames;
+    int srcfreq = mpglib_freqs[opaque->mp.fr.sampling_frequency];
+    int dstfreq = (int) ctx->device->streamFormat.mSampleRate;
+    ALsizei outsize = samples * sizeof (SInt16) * 2;
+    SInt16 *outbuf = (UInt16 *) alloca(outsize);
+    int decoded = doMp3Decode(opaque, outbuf, outsize);
+
+    src->bufferReadIndex = 1;  // hack to get this to not reinitialize the buffer in alContext.c.
+
+    if (srcfreq != dstfreq)
+    {
+    	ALfloat ratio = ((ALfloat) dstfreq) / ((ALfloat) srcfreq);
+        ALsizei newsize = ((ALsizei) ((outsize >> 2) * ratio)) << 2;
+        SInt16 *resampled = (SInt16 *) alloca(newsize);
+        __alResampleStereo16(outbuf, outsize, resampled, newsize);
+        outbuf = resampled;
+        outsize = newsize;
+    } // if
+
+    {  // !!! FIXME: make mixers generic against blocks of memory so I can
+       // !!! FIXME:  use them here.
+    register SInt16 *in = outbuf;
+    register Float32 *dst;
+    register Float32 *max;
+    register Float32 gainLeft;
+    register Float32 gainRight;
+
+	gainLeft = gainRight = src->gain * ctx->listener.Gain;
+    gainLeft *= ctx->device->speakergains[0];
+    gainRight *= ctx->device->speakergains[1];
+
+    // Too quiet to be worth playing? Just skip ahead in the buffer appropriately.
+    if ((gainLeft > MINVOL) || (gainRight > MINVOL))
+    {
+        // Mix to the output buffer...
+        dst = _dst;
+        max = dst + (decoded * channels);
+        in = (SInt16 *) outbuf;
+
+        gainLeft *= DIVBY32767;
+        gainRight *= DIVBY32767;
+        while (dst < max)
+        {
+            dst[0] += ((Float32) in[0]) * gainLeft;
+            dst[1] += ((Float32) in[1]) * gainRight;
+            in += 2;
+            dst += channels;  // skip rest of channels.
+        } // while
+    } // if
+    }
+
+    return(frames - decoded);
+} // __alMixMP3
+
+
+static ALboolean __alPrepareBufferMP3(ALcontext *ctx,
+                                      ALsource *src,
+                                      ALbuffer *buf)
+{
+    MP3Opaque *o = calloc(1, sizeof (MP3Opaque));
+    if (o == NULL)
+    {
+        __alSetError(AL_OUT_OF_MEMORY);
+        return(AL_FALSE);
+    } // if
+
+    InitMP3(&o->mp);
+    decodeMP3(&o->mp, buf->mixData, buf->allocatedSpace,
+              (char *) &o->outbuf, sizeof (o->outbuf), &o->outleft);
+
+    src->opaque = o;
+    return(AL_TRUE);
+} // __alPrepareBufferMP3
+
+
+static ALvoid __alProcessedBufferMP3(ALsource *src, ALbuffer *buf)
+{
+    MP3Opaque *opaque = (MP3Opaque *) src->opaque;
+    if (opaque != NULL)
+    {
+        ExitMP3(&opaque->mp);
+        free(opaque);
+    } // if
+} // __alProcessedBufferMP3
+
+
+static ALvoid __alRewindBufferMP3(ALsource *src, ALbuffer *buf)
+{
+    MP3Opaque *o = (MP3Opaque *) src->opaque;
+    if (o != NULL)
+    {
+        ExitMP3(&o->mp);
+        InitMP3(&o->mp);
+        decodeMP3(&o->mp, buf->mixData, buf->allocatedSpace,
+                  (char *) &o->outbuf, sizeof (o->outbuf), &o->outleft);
+        o->outpos = 0;
+    } // if
+} // __alRewindBufferMP3
+
+
+static ALvoid __alDeleteBufferMP3(ALbuffer *buf)
+{
+    // no-op ... we don't allocate anything as buffer-instance data currently.
+} // __alDeleteBufferMP3
+
+
+ALvoid __alBufferDataFromMP3(ALbuffer *buf)
+{
+    buf->prepareBuffer = __alPrepareBufferMP3;
+    buf->processedBuffer = __alProcessedBufferMP3;
+    buf->rewindBuffer = __alRewindBufferMP3;
+    buf->deleteBuffer = __alDeleteBufferMP3;
+    buf->mixFunc = __alMixMP3;
+} // __alBufferDataFromMP3
+
+// end of al_ext_mp3.c ...
+
diff --git a/osx/AL_EXT_mp3/mpglib/CHANGES b/osx/AL_EXT_mp3/mpglib/CHANGES
@@ -0,0 +1,4 @@
+14/Oct/1999: 
+  - VBR fix
+  - Layer2 and Layer1 added
+
diff --git a/osx/AL_EXT_mp3/mpglib/Makefile.am b/osx/AL_EXT_mp3/mpglib/Makefile.am
@@ -0,0 +1,24 @@
+noinst_LTLIBRARIES = libmpglib.la
+
+INCLUDES = -I$(top_srcdir)
+libmpglib_la_CFLAGS = -DLAYER1 -DLAYER2 -DLAYER3
+
+if USE_MPGLIB
+libmpglib_la_SOURCES =	\
+	mpglib_common.c     \
+	huffman.h           \
+	layer1.c            \
+	tabinit.c           \
+	dct64_i386.c        \
+	interface.c         \
+	layer2.c            \
+	mpg123_sdlsound.h   \
+	decode_i386.c       \
+	l2tables.h          \
+	layer3.c            \
+	mpglib_sdlsound.h
+else
+libmpglib_la_SOURCES =
+endif
+
+#EXTRA_DIST = FAQ README CHANGES TODO
diff --git a/osx/AL_EXT_mp3/mpglib/README b/osx/AL_EXT_mp3/mpglib/README
@@ -0,0 +1,39 @@
+MP3 library
+-----------
+Version 0.2a
+
+This decoder is a 'light' version (thrown out all unnecessay parts)
+from the mpg123 package. I made this for a company.
+
+Currently only Layer3 is enabled to save some space. Layer1,2 isn't
+tested at all. The interface will not change significantly. 
+A backport to the mpg123 package is planed.
+
+compiled and tested only on Solaris 2.6
+main.c contains a simple demo application for library.
+
+COPYING: you may use this source under LGPL terms! 
+  (Yes, I switched to LGPL for the _mpglib_ part!)
+
+PLEASE NOTE: This software may contain patented algorithms (at least
+  patented in some countries). It may be not allowed to sell/use products
+  based on this source code in these countries. Check this out first!
+
+COPYRIGHT of MP3 music:
+  Please note, that the duplicating of copyrighted music without explicit
+  permission violates the rights of the owner.
+
+SENDING PATCHES:
+  The current version is under LGPL. Please consider this when sending patches or 
+  changes. I also want to have the freedom to sell the code to companies that
+  cannot or do not want to use the code under LGPL. So, if you send me 
+  significant patches, I need your explicit permission to do this. Of course, 
+  there will always be the LGPLed open source version of the 100% same code.
+  In the case you cannot accept this: the code is free, it's your freedom 
+  to distribute your changes again under LGPL. 
+
+FEEDBACK:
+  I'm interessted to here from you, when you use this package as part
+  of another project.
+
+
diff --git a/osx/AL_EXT_mp3/mpglib/README-sdlsound b/osx/AL_EXT_mp3/mpglib/README-sdlsound
@@ -0,0 +1,7 @@
+This package, according to the README, is under the LGPL, which means it uses
+the same license as SDL_sound.
+
+mpglib is part of mpg123, which can be found at http://www.mpg123.de/  ...
+
+--ryan.
+
diff --git a/osx/AL_EXT_mp3/mpglib/TODO b/osx/AL_EXT_mp3/mpglib/TODO