--- /dev/null
+/***************************************************************************
+ 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 <tdebug.h>
+#include <tstring.h>
+
+#include "mpegproperties.h"
+#include "mpegfile.h"
+#include "xingheader.h"
+
+using namespace TagLib;
+
+class MPEG::Properties::PropertiesPrivate
+{
+public:
+ PropertiesPrivate(File *f, ReadStyle s) :
+ file(f),
+ xingHeader(0),
+ style(s),
+ length(0),
+ bitrate(0),
+ sampleRate(0),
+ channels(0),
+ layer(0),
+ version(Header::Version1),
+ channelMode(Header::Stereo),
+ protectionEnabled(false),
+ isCopyrighted(false),
+ isOriginal(false) {}
+
+ ~PropertiesPrivate()
+ {
+ delete xingHeader;
+ }
+
+ File *file;
+ XingHeader *xingHeader;
+ ReadStyle style;
+ int length;
+ int bitrate;
+ int sampleRate;
+ int channels;
+ int layer;
+ Header::Version version;
+ Header::ChannelMode channelMode;
+ bool protectionEnabled;
+ bool isCopyrighted;
+ bool isOriginal;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+// public members
+////////////////////////////////////////////////////////////////////////////////
+
+MPEG::Properties::Properties(File *file, ReadStyle style) : AudioProperties(style)
+{
+ d = new PropertiesPrivate(file, style);
+
+ if(file && file->isOpen())
+ read();
+}
+
+MPEG::Properties::~Properties()
+{
+ delete d;
+}
+
+int MPEG::Properties::length() const
+{
+ return d->length;
+}
+
+int MPEG::Properties::bitrate() const
+{
+ return d->bitrate;
+}
+
+int MPEG::Properties::sampleRate() const
+{
+ return d->sampleRate;
+}
+
+int MPEG::Properties::channels() const
+{
+ return d->channels;
+}
+
+const MPEG::XingHeader *MPEG::Properties::xingHeader() const
+{
+ return d->xingHeader;
+}
+
+MPEG::Header::Version MPEG::Properties::version() const
+{
+ return d->version;
+}
+
+int MPEG::Properties::layer() const
+{
+ return d->layer;
+}
+
+bool MPEG::Properties::protectionEnabled() const
+{
+ return d->protectionEnabled;
+}
+
+MPEG::Header::ChannelMode MPEG::Properties::channelMode() const
+{
+ return d->channelMode;
+}
+
+bool MPEG::Properties::isCopyrighted() const
+{
+ return d->isCopyrighted;
+}
+
+bool MPEG::Properties::isOriginal() const
+{
+ return d->isOriginal;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// private members
+////////////////////////////////////////////////////////////////////////////////
+
+void MPEG::Properties::read()
+{
+ // Since we've likely just looked for the ID3v1 tag, start at the end of the
+ // file where we're least likely to have to have to move the disk head.
+
+ long last = d->file->lastFrameOffset();
+
+ if(last < 0) {
+ debug("MPEG::Properties::read() -- Could not find a valid last MPEG frame in the stream.");
+ return;
+ }
+
+ d->file->seek(last);
+ Header lastHeader(d->file->readBlock(4));
+
+ long first = d->file->firstFrameOffset();
+
+ if(first < 0) {
+ debug("MPEG::Properties::read() -- Could not find a valid first MPEG frame in the stream.");
+ return;
+ }
+
+ if(!lastHeader.isValid()) {
+
+ long pos = last;
+
+ while(pos > first) {
+
+ pos = d->file->previousFrameOffset(pos);
+
+ if(pos < 0)
+ break;
+
+ d->file->seek(pos);
+ Header header(d->file->readBlock(4));
+
+ if(header.isValid()) {
+ lastHeader = header;
+ last = pos;
+ break;
+ }
+ }
+ }
+
+ // Now jump back to the front of the file and read what we need from there.
+
+ d->file->seek(first);
+ Header firstHeader(d->file->readBlock(4));
+
+ if(!firstHeader.isValid() || !lastHeader.isValid()) {
+ debug("MPEG::Properties::read() -- Page headers were invalid.");
+ return;
+ }
+
+ // Check for a Xing header that will help us in gathering information about a
+ // VBR stream.
+
+ int xingHeaderOffset = MPEG::XingHeader::xingHeaderOffset(firstHeader.version(),
+ firstHeader.channelMode());
+
+ d->file->seek(first + xingHeaderOffset);
+ d->xingHeader = new XingHeader(d->file->readBlock(16));
+
+ // Read the length and the bitrate from the Xing header.
+
+ if(d->xingHeader->isValid() &&
+ firstHeader.sampleRate() > 0 &&
+ d->xingHeader->totalFrames() > 0)
+ {
+ double timePerFrame =
+ double(firstHeader.samplesPerFrame()) / firstHeader.sampleRate();
+
+ double length = timePerFrame * d->xingHeader->totalFrames();
+
+ d->length = int(length);
+ d->bitrate = d->length > 0 ? d->xingHeader->totalSize() * 8 / length / 1000 : 0;
+ }
+ else {
+ // Since there was no valid Xing header found, we hope that we're in a constant
+ // bitrate file.
+
+ delete d->xingHeader;
+ d->xingHeader = 0;
+
+ // TODO: Make this more robust with audio property detection for VBR without a
+ // Xing header.
+
+ if(firstHeader.frameLength() > 0 && firstHeader.bitrate() > 0) {
+ int frames = (last - first) / firstHeader.frameLength() + 1;
+
+ d->length = int(float(firstHeader.frameLength() * frames) /
+ float(firstHeader.bitrate() * 125) + 0.5);
+ d->bitrate = firstHeader.bitrate();
+ }
+ }
+
+
+ d->sampleRate = firstHeader.sampleRate();
+ d->channels = firstHeader.channelMode() == Header::SingleChannel ? 1 : 2;
+ d->version = firstHeader.version();
+ d->layer = firstHeader.layer();
+ d->protectionEnabled = firstHeader.protectionEnabled();
+ d->channelMode = firstHeader.channelMode();
+ d->isCopyrighted = firstHeader.isCopyrighted();
+ d->isOriginal = firstHeader.isOriginal();
+}
projects / someplayer / blobdiff