ulawaudiofilter.hh

流媒体传输协议的实现代码,非常有用.可以支持rtsp mms等流媒体传输协议

/**********
This library is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the
Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)

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
**********/
// "liveMedia"
// Copyright (c) 1996-2004 Live Networks, Inc.  All rights reserved.
// Filters for converting between raw PCM audio and uLaw
// C++ header

#ifndef _ULAW_AUDIO_FILTER_HH
#define _ULAW_AUDIO_FILTER_HH

#ifndef _FRAMED_FILTER_HH
#include "FramedFilter.hh"
#endif

////////// 16-bit PCM (in various byte orderings) -> 8-bit u-Law //////////

class uLawFromPCMAudioSource: public FramedFilter {
public:
  static uLawFromPCMAudioSource*
  createNew(UsageEnvironment& env, FramedSource* inputSource,
	    int byteOrdering = 0);
  // "byteOrdering" == 0 => host order (the default)
  // "byteOrdering" == 1 => little-endian order
  // "byteOrdering" == 2 => network (i.e., big-endian) order

protected:
  uLawFromPCMAudioSource(UsageEnvironment& env, FramedSource* inputSource,
			 int byteOrdering);
      // called only by createNew()
  virtual ~uLawFromPCMAudioSource();

private:
  // Redefined virtual functions:
  virtual void doGetNextFrame();

private:
  static void afterGettingFrame(void* clientData, unsigned frameSize,
				unsigned numTruncatedBytes,
				struct timeval presentationTime,
				unsigned durationInMicroseconds);
  void afterGettingFrame1(unsigned frameSize,
			  unsigned numTruncatedBytes,
			  struct timeval presentationTime,
			  unsigned durationInMicroseconds);

private:
  int fByteOrdering;
  unsigned char* fInputBuffer;
  unsigned fInputBufferSize;
};


////////// u-Law -> 16-bit PCM (in host order) //////////

class PCMFromuLawAudioSource: public FramedFilter {
public:
  static PCMFromuLawAudioSource*
  createNew(UsageEnvironment& env, FramedSource* inputSource);

protected:
  PCMFromuLawAudioSource(UsageEnvironment& env,
			 FramedSource* inputSource);
      // called only by createNew()
  virtual ~PCMFromuLawAudioSource();

private:
  // Redefined virtual functions:
  virtual void doGetNextFrame();

private:
  static void afterGettingFrame(void* clientData, unsigned frameSize,
				unsigned numTruncatedBytes,
				struct timeval presentationTime,
				unsigned durationInMicroseconds);
  void afterGettingFrame1(unsigned frameSize,
			  unsigned numTruncatedBytes,
			  struct timeval presentationTime,
			  unsigned durationInMicroseconds);

private:
  unsigned char* fInputBuffer;
  unsigned fInputBufferSize;
};


////////// 16-bit values (in host order) -> 16-bit network order //////////

class NetworkFromHostOrder16: public FramedFilter {
public:
  static NetworkFromHostOrder16*
  createNew(UsageEnvironment& env, FramedSource* inputSource);

protected:
  NetworkFromHostOrder16(UsageEnvironment& env, FramedSource* inputSource);
      // called only by createNew()
  virtual ~NetworkFromHostOrder16();

private:
  // Redefined virtual functions:
  virtual void doGetNextFrame();

private:
  static void afterGettingFrame(void* clientData, unsigned frameSize,
				unsigned numTruncatedBytes,
				struct timeval presentationTime,
				unsigned durationInMicroseconds);
  void afterGettingFrame1(unsigned frameSize,
			  unsigned numTruncatedBytes,
			  struct timeval presentationTime,
			  unsigned durationInMicroseconds);
};


////////// 16-bit values (in network order) -> 16-bit host order //////////

class HostFromNetworkOrder16: public FramedFilter {
public:
  static HostFromNetworkOrder16*
  createNew(UsageEnvironment& env, FramedSource* inputSource);

protected:
  HostFromNetworkOrder16(UsageEnvironment& env, FramedSource* inputSource);
      // called only by createNew()
  virtual ~HostFromNetworkOrder16();

private:
  // Redefined virtual functions:
  virtual void doGetNextFrame();

private:
  static void afterGettingFrame(void* clientData, unsigned frameSize,
				unsigned numTruncatedBytes,
				struct timeval presentationTime,
				unsigned durationInMicroseconds);
  void afterGettingFrame1(unsigned frameSize,
			  unsigned numTruncatedBytes,
			  struct timeval presentationTime,
			  unsigned durationInMicroseconds);
};


////////// 16-bit values: little-endian <-> big-endian //////////

class EndianSwap16: public FramedFilter {
public:
  static EndianSwap16* createNew(UsageEnvironment& env, FramedSource* inputSource);

protected:
  EndianSwap16(UsageEnvironment& env, FramedSource* inputSource);
      // called only by createNew()
  virtual ~EndianSwap16();

private:
  // Redefined virtual functions:
  virtual void doGetNextFrame();

private:
  static void afterGettingFrame(void* clientData, unsigned frameSize,
				unsigned numTruncatedBytes,
				struct timeval presentationTime,
				unsigned durationInMicroseconds);
  void afterGettingFrame1(unsigned frameSize,
			  unsigned numTruncatedBytes,
			  struct timeval presentationTime,
			  unsigned durationInMicroseconds);
};

#endif