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-rw-r--r--libs/taglib/taglib/mpeg/mpegheader.cpp276
1 files changed, 276 insertions, 0 deletions
diff --git a/libs/taglib/taglib/mpeg/mpegheader.cpp b/libs/taglib/taglib/mpeg/mpegheader.cpp
new file mode 100644
index 0000000000..5238498b2e
--- /dev/null
+++ b/libs/taglib/taglib/mpeg/mpegheader.cpp
@@ -0,0 +1,276 @@
+/***************************************************************************
+ copyright : (C) 2002 - 2008 by Scott Wheeler
+ email : wheeler@kde.org
+ ***************************************************************************/
+
+/***************************************************************************
+ * This library is free software; you can redistribute it and/or modify *
+ * it under the terms of the GNU Lesser General Public License version *
+ * 2.1 as published by the Free Software Foundation. *
+ * *
+ * 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 *
+ * Lesser General Public License for more details. *
+ * *
+ * You should have received a copy of the GNU Lesser 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 *
+ * *
+ * Alternatively, this file is available under the Mozilla Public *
+ * License Version 1.1. You may obtain a copy of the License at *
+ * http://www.mozilla.org/MPL/ *
+ ***************************************************************************/
+
+#include <bitset>
+
+#include <tbytevector.h>
+#include <tstring.h>
+#include <tdebug.h>
+
+#include "mpegheader.h"
+
+using namespace TagLib;
+
+class MPEG::Header::HeaderPrivate : public RefCounter
+{
+public:
+ HeaderPrivate() :
+ isValid(false),
+ version(Version1),
+ layer(0),
+ protectionEnabled(false),
+ sampleRate(0),
+ isPadded(false),
+ channelMode(Stereo),
+ isCopyrighted(false),
+ isOriginal(false),
+ frameLength(0),
+ samplesPerFrame(0) {}
+
+ bool isValid;
+ Version version;
+ int layer;
+ bool protectionEnabled;
+ int bitrate;
+ int sampleRate;
+ bool isPadded;
+ ChannelMode channelMode;
+ bool isCopyrighted;
+ bool isOriginal;
+ int frameLength;
+ int samplesPerFrame;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+// public members
+////////////////////////////////////////////////////////////////////////////////
+
+MPEG::Header::Header(const ByteVector &data)
+{
+ d = new HeaderPrivate;
+ parse(data);
+}
+
+MPEG::Header::Header(const Header &h) : d(h.d)
+{
+ d->ref();
+}
+
+MPEG::Header::~Header()
+{
+ if (d->deref())
+ delete d;
+}
+
+bool MPEG::Header::isValid() const
+{
+ return d->isValid;
+}
+
+MPEG::Header::Version MPEG::Header::version() const
+{
+ return d->version;
+}
+
+int MPEG::Header::layer() const
+{
+ return d->layer;
+}
+
+bool MPEG::Header::protectionEnabled() const
+{
+ return d->protectionEnabled;
+}
+
+int MPEG::Header::bitrate() const
+{
+ return d->bitrate;
+}
+
+int MPEG::Header::sampleRate() const
+{
+ return d->sampleRate;
+}
+
+bool MPEG::Header::isPadded() const
+{
+ return d->isPadded;
+}
+
+MPEG::Header::ChannelMode MPEG::Header::channelMode() const
+{
+ return d->channelMode;
+}
+
+bool MPEG::Header::isCopyrighted() const
+{
+ return d->isCopyrighted;
+}
+
+bool MPEG::Header::isOriginal() const
+{
+ return d->isOriginal;
+}
+
+int MPEG::Header::frameLength() const
+{
+ return d->frameLength;
+}
+
+int MPEG::Header::samplesPerFrame() const
+{
+ return d->samplesPerFrame;
+}
+
+MPEG::Header &MPEG::Header::operator=(const Header &h)
+{
+ if(&h == this)
+ return *this;
+
+ if(d->deref())
+ delete d;
+
+ d = h.d;
+ d->ref();
+ return *this;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// private members
+////////////////////////////////////////////////////////////////////////////////
+
+void MPEG::Header::parse(const ByteVector &data)
+{
+ if(data.size() < 4 || uchar(data[0]) != 0xff) {
+ debug("MPEG::Header::parse() -- First byte did not mactch MPEG synch.");
+ return;
+ }
+
+ std::bitset<32> flags(data.toUInt());
+
+ // Check for the second byte's part of the MPEG synch
+
+ if(!flags[23] || !flags[22] || !flags[21]) {
+ debug("MPEG::Header::parse() -- Second byte did not mactch MPEG synch.");
+ return;
+ }
+
+ // Set the MPEG version
+
+ if(!flags[20] && !flags[19])
+ d->version = Version2_5;
+ else if(flags[20] && !flags[19])
+ d->version = Version2;
+ else if(flags[20] && flags[19])
+ d->version = Version1;
+
+ // Set the MPEG layer
+
+ if(!flags[18] && flags[17])
+ d->layer = 3;
+ else if(flags[18] && !flags[17])
+ d->layer = 2;
+ else if(flags[18] && flags[17])
+ d->layer = 1;
+
+ d->protectionEnabled = !flags[16];
+
+ // Set the bitrate
+
+ static const int bitrates[2][3][16] = {
+ { // Version 1
+ { 0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448, 0 }, // layer 1
+ { 0, 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384, 0 }, // layer 2
+ { 0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 0 } // layer 3
+ },
+ { // Version 2 or 2.5
+ { 0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256, 0 }, // layer 1
+ { 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 0 }, // layer 2
+ { 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 0 } // layer 3
+ }
+ };
+
+ const int versionIndex = d->version == Version1 ? 0 : 1;
+ const int layerIndex = d->layer > 0 ? d->layer - 1 : 0;
+
+ // The bitrate index is encoded as the first 4 bits of the 3rd byte,
+ // i.e. 1111xxxx
+
+ int i = uchar(data[2]) >> 4;
+
+ d->bitrate = bitrates[versionIndex][layerIndex][i];
+
+ // Set the sample rate
+
+ static const int sampleRates[3][4] = {
+ { 44100, 48000, 32000, 0 }, // Version 1
+ { 22050, 24000, 16000, 0 }, // Version 2
+ { 11025, 12000, 8000, 0 } // Version 2.5
+ };
+
+ // The sample rate index is encoded as two bits in the 3nd byte, i.e. xxxx11xx
+
+ i = uchar(data[2]) >> 2 & 0x03;
+
+ d->sampleRate = sampleRates[d->version][i];
+
+ if(d->sampleRate == 0) {
+ debug("MPEG::Header::parse() -- Invalid sample rate.");
+ return;
+ }
+
+ // The channel mode is encoded as a 2 bit value at the end of the 3nd byte,
+ // i.e. xxxxxx11
+
+ d->channelMode = ChannelMode((uchar(data[3]) & 0xC0) >> 6);
+
+ // TODO: Add mode extension for completeness
+
+ d->isOriginal = flags[2];
+ d->isCopyrighted = flags[3];
+ d->isPadded = flags[9];
+
+ // Calculate the frame length
+
+ if(d->layer == 1)
+ d->frameLength = 24000 * 2 * d->bitrate / d->sampleRate + int(d->isPadded);
+ else
+ d->frameLength = 72000 * d->bitrate / d->sampleRate + int(d->isPadded);
+
+ // Samples per frame
+
+ static const int samplesPerFrame[3][2] = {
+ // MPEG1, 2/2.5
+ { 384, 384 }, // Layer I
+ { 1152, 1152 }, // Layer II
+ { 1152, 576 } // Layer III
+ };
+
+ d->samplesPerFrame = samplesPerFrame[layerIndex][versionIndex];
+
+ // Now that we're done parsing, set this to be a valid frame.
+
+ d->isValid = true;
+}
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