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136 lines
3.9 KiB
136 lines
3.9 KiB
/* aKode: Decoder abstract-type
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Copyright (C) 2004 Allan Sandfeld Jensen <kde@carewolf.com>
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public License
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along with this library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 51 Franklin Steet, Fifth Floor,
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Boston, MA 02110-1301, USA.
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*/
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#ifndef _AKODE_DECODER_H
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#define _AKODE_DECODER_H
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#include "pluginhandler.h"
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#include "akode_export.h"
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namespace aKode {
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class AudioConfiguration;
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class File;
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class AudioFrame;
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//! A generic interface for all decoders
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/*!
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* The Decoder works by decoding one audio-frame at a time. It is up to
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* the decoder itself to decide how large a frame is.
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*/
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class AKODE_EXPORT Decoder {
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public:
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virtual ~Decoder() {};
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/*!
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* Reads one frame from the decoder.
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* It is advisable to reuse the the same frame for every readFrame()-call,
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* as the frame size is likely to be constant in the same file,
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* which saves re-allocations.
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*
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* If readFrame returns false, it can be one of three things:
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* 1. End-of-File (check eof()).
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* 2. Fatal error (check error()).
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* 3. Recoverable error (call readFrame again)
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*/
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virtual bool readFrame(AudioFrame*) = 0;
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/*!
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* Returns the length of the file/stream in milliseconds.
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* Returns -1 if the length is unknown.
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*/
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virtual long length() = 0;
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/*!
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* Returns the current position in file/stream in milliseconds.
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* Returns -1 if the position is unknown.
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*/
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virtual long position() = 0;
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/*!
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* Attempts a seek to \a pos milliseconds into the file/stream.
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* Returns true if succesfull.
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*/
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virtual bool seek(long pos) = 0;
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/*!
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* Returns true if the decoder is seekable
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*/
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virtual bool seekable() = 0;
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/*!
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* Returns true if the decoder has reached the end-of-file/stream
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*/
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virtual bool eof() = 0;
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/*!
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* Returns true if the decoder has encountered a non-recoverable error
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*/
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virtual bool error() = 0;
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/*!
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* Returns the configuration of the decoded stream.
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* Returns 0 if unknown.
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*/
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virtual const AudioConfiguration* audioConfiguration() = 0;
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};
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/*!
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* Parent class for decoder plugins
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*/
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class DecoderPlugin {
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public:
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/*!
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* Asks the plugin to open a Decoder, returns 0 if the
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* plugin could not.
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*/
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virtual Decoder* openDecoder(File *) { return 0; };
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/*!
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* Old version version of openDecoder.
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* \deprecated
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*/
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Decoder* openFrameDecoder(File *src) { return openDecoder(src); };
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};
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/*!
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* Handler for decoder-plugins.
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*/
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class AKODE_EXPORT DecoderPluginHandler : public PluginHandler, public DecoderPlugin {
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public:
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static list<string> listDecoderPlugins();
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DecoderPluginHandler() : decoder_plugin(0) {};
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DecoderPluginHandler(const string name);
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/*!
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* Open a Decoder for the File \a src. Returns 0 if unsuccesfull
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*/
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Decoder* openDecoder(File *src);
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/*!
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* Old version version of openDecoder.
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* \deprecated
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*/
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Decoder* openFrameDecoder(File *src) { return openDecoder(src); };
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/*!
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* Loads a decoder-plugin named \a name (xiph, mpc, mpeg..)
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*/
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virtual bool load(const string name);
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virtual void unload();
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bool isLoaded() { return decoder_plugin != 0; };
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protected:
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DecoderPlugin* decoder_plugin;
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};
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} // namespace
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#endif
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