src/ALAC/* : Big code dump of code for Apple's ALAC file format.

libsndfile · Mar 3, 2012 · 297cb9c · 297cb9c
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diff --git a/ChangeLog b/ChangeLog
@@ -1,3 +1,12 @@
+2012-02-03  Erik de Castro Lopo  <erikd AT mega-nerd DOT com>
+
+    * src/ALAC/*
+    Big code dump of code for Apple's ALAC file format. This copyyright to this
+    code is owned by Apple who have released it under an Apache style license.
+    A few modifications were made to allow this to be integrated into libsndfile
+    but unfortunately the history of those changes were lost because they were
+    developed in a Bzr tree and during that time libsndfile moved to Git.
+
 2012-02-02  Erik de Castro Lopo  <erikd AT mega-nerd DOT com>
 
     * src/aiff.c src/wav.c

diff --git a/README b/README
@@ -20,6 +20,9 @@ Bormann. Their original code can be found at :
 The src/G72x directory contains code written and released by Sun Microsystems
 under a suitably free license.
 
+The src/ALAC directory contains code written and released by Apple Inc and
+released under the Apache license.
+
 
 LINUX
 -----

diff --git a/src/ALAC/ALACAudioTypes.h b/src/ALAC/ALACAudioTypes.h
@@ -0,0 +1,200 @@
+/*
+ * Copyright (c) 2011 Apple Inc. All rights reserved.
+ *
+ * @APPLE_APACHE_LICENSE_HEADER_START@
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * @APPLE_APACHE_LICENSE_HEADER_END@
+ */
+
+/*
+	File:		ALACAudioTypes.h
+*/
+
+#ifndef ALACAUDIOTYPES_H
+#define ALACAUDIOTYPES_H
+
+/* Force these Mac OS specific things to zero. */
+#define PRAGMA_STRUCT_ALIGN 0
+#define PRAGMA_STRUCT_PACKPUSH 0
+#define PRAGMA_STRUCT_PACK 0
+#define PRAGMA_ONCE 0
+#define PRAGMA_MARK 0
+
+
+#if PRAGMA_ONCE
+#pragma once
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+
+#include "sfendian.h"
+
+#if CPU_IS_BIG_ENDIAN == 1
+#define TARGET_RT_BIG_ENDIAN 1
+#else
+#define TARGET_RT_BIG_ENDIAN 0
+#endif
+
+#define kChannelAtomSize 12
+
+enum
+{
+    kALAC_UnimplementedError   = -4,
+    kALAC_FileNotFoundError    = -43,
+    kALAC_ParamError           = -50,
+    kALAC_MemFullError         = -108,
+    fALAC_FrameLengthError     = -666,
+};
+
+enum
+{
+    kALACFormatAppleLossless = MAKE_MARKER ('a', 'l', 'a', 'c'),
+    kALACFormatLinearPCM = MAKE_MARKER ('l', 'p', 'c', 'm')
+};
+
+enum
+{
+    kALACMaxChannels	= 8,
+    kALACMaxEscapeHeaderBytes = 8,
+    kALACMaxSearches	= 16,
+    kALACMaxCoefs		= 16,
+    kALACDefaultFramesPerPacket = 4096
+};
+
+typedef uint32_t ALACChannelLayoutTag;
+
+enum
+{
+    kALACFormatFlagIsFloat                     = (1 << 0),     // 0x1
+    kALACFormatFlagIsBigEndian                 = (1 << 1),     // 0x2
+    kALACFormatFlagIsSignedInteger             = (1 << 2),     // 0x4
+    kALACFormatFlagIsPacked                    = (1 << 3),     // 0x8
+    kALACFormatFlagIsAlignedHigh               = (1 << 4),     // 0x10
+};
+
+enum
+{
+#if TARGET_RT_BIG_ENDIAN
+    kALACFormatFlagsNativeEndian       = kALACFormatFlagIsBigEndian
+#else
+    kALACFormatFlagsNativeEndian       = 0
+#endif
+};
+
+// this is required to be an IEEE 64bit float
+typedef double alac_float64_t;
+
+// These are the Channel Layout Tags used in the Channel Layout Info portion of the ALAC magic cookie
+enum
+{
+    kALACChannelLayoutTag_Mono          = (100<<16) | 1,    // C
+    kALACChannelLayoutTag_Stereo        = (101<<16) | 2,	// L R
+    kALACChannelLayoutTag_MPEG_3_0_B    = (113<<16) | 3,	// C L R
+    kALACChannelLayoutTag_MPEG_4_0_B    = (116<<16) | 4,	// C L R Cs
+    kALACChannelLayoutTag_MPEG_5_0_D    = (120<<16) | 5,    // C L R Ls Rs
+    kALACChannelLayoutTag_MPEG_5_1_D    = (124<<16) | 6,	// C L R Ls Rs LFE
+    kALACChannelLayoutTag_AAC_6_1       = (142<<16) | 7,	// C L R Ls Rs Cs LFE
+    kALACChannelLayoutTag_MPEG_7_1_B	= (127<<16) | 8     // C Lc Rc L R Ls Rs LFE    (doc: IS-13818-7 MPEG2-AAC)
+};
+
+// ALAC currently only utilizes these channels layouts. There is a one for one correspondance between a
+// given number of channels and one of these layout tags
+static const ALACChannelLayoutTag	ALACChannelLayoutTags[kALACMaxChannels] =
+{
+    kALACChannelLayoutTag_Mono,         // C
+    kALACChannelLayoutTag_Stereo,		// L R
+    kALACChannelLayoutTag_MPEG_3_0_B,	// C L R
+    kALACChannelLayoutTag_MPEG_4_0_B,	// C L R Cs
+    kALACChannelLayoutTag_MPEG_5_0_D,	// C L R Ls Rs
+    kALACChannelLayoutTag_MPEG_5_1_D,	// C L R Ls Rs LFE
+    kALACChannelLayoutTag_AAC_6_1,		// C L R Ls Rs Cs LFE
+    kALACChannelLayoutTag_MPEG_7_1_B	// C Lc Rc L R Ls Rs LFE    (doc: IS-13818-7 MPEG2-AAC)
+};
+
+// AudioChannelLayout from CoreAudioTypes.h. We never need the AudioChannelDescription so we remove it
+struct ALACAudioChannelLayout
+{
+    ALACChannelLayoutTag          mChannelLayoutTag;
+    uint32_t                      mChannelBitmap;
+    uint32_t                      mNumberChannelDescriptions;
+};
+typedef struct ALACAudioChannelLayout ALACAudioChannelLayout;
+
+struct AudioFormatDescription
+{
+    alac_float64_t mSampleRate;
+    uint32_t  mFormatID;
+    uint32_t  mFormatFlags;
+    uint32_t  mBytesPerPacket;
+    uint32_t  mFramesPerPacket;
+    uint32_t  mBytesPerFrame;
+    uint32_t  mChannelsPerFrame;
+    uint32_t  mBitsPerChannel;
+    uint32_t  mReserved;
+};
+typedef struct AudioFormatDescription  AudioFormatDescription;
+
+/* Lossless Definitions */
+
+enum
+{
+	kALACCodecFormat		= MAKE_MARKER ('a', 'l', 'a', 'c'),
+	kALACVersion			= 0,
+	kALACCompatibleVersion	= kALACVersion,
+	kALACDefaultFrameSize	= 4096
+};
+
+// note: this struct is wrapped in an 'alac' atom in the sample description extension area
+// note: in QT movies, it will be further wrapped in a 'wave' atom surrounded by 'frma' and 'term' atoms
+typedef struct ALACSpecificConfig
+{
+	uint32_t				frameLength;
+	uint8_t					compatibleVersion;
+	uint8_t					bitDepth;							// max 32
+	uint8_t					pb;									// 0 <= pb <= 255
+	uint8_t					mb;
+	uint8_t					kb;
+	uint8_t					numChannels;
+	uint16_t				maxRun;
+	uint32_t				maxFrameBytes;
+	uint32_t				avgBitRate;
+	uint32_t				sampleRate;
+
+} ALACSpecificConfig;
+
+
+// The AudioChannelLayout atom type is not exposed yet so define it here
+enum
+{
+	AudioChannelLayoutAID = MAKE_MARKER ('c', 'h', 'a', 'n')
+};
+
+#if PRAGMA_STRUCT_ALIGN
+    #pragma options align=reset
+#elif PRAGMA_STRUCT_PACKPUSH
+    #pragma pack(pop)
+#elif PRAGMA_STRUCT_PACK
+    #pragma pack()
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif	/* ALACAUDIOTYPES_H */