/* * ---------------------------------------------------------------------------- * "THE BEER-WARE LICENSE" (Revision 42): * wrote this file. As long as you retain this notice you * can do whatever you want with this stuff. If we meet some day, and you think * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp * ---------------------------------------------------------------------------- * * Extract DTMF signals from 16 bit PCM audio * * Originally written by Poul-Henning Kamp * Made into a C++ class by Roger Hardiman , January 2002 * * $Revision: 21788 $ * $Author: rjongbloed $ * $Date: 2008-12-12 05:42:13 +0000 (Fri, 12 Dec 2008) $ */ #ifndef PTLIB_DTMF_H #define PTLIB_DTMF_H #ifdef P_USE_PRAGMA #pragma interface #endif class PDTMFDecoder : public PObject { PCLASSINFO(PDTMFDecoder, PObject) public: PDTMFDecoder(); PString Decode(const short * sampleData, PINDEX numSamples, unsigned mult = 1, unsigned div = 1); protected: enum { NumTones = 10 }; // key lookup table (initialised once) char key[256]; // frequency table (initialised once) int p1[NumTones]; // variables to be retained on each cycle of the decode function int h[NumTones], k[NumTones], y[NumTones]; int nn, so, ia; }; /** This class can be used to generate PCM data for tones (such as telephone calling tones and DTMF) at a sample rate of 8khz. The class contains a master volume which is applied as well as the individual tone volumes. Thus a master volume ot 50% and a tone voluem of 50% would result in a net volume of 25%. Tones may be described via a list of descriptor strings based on an ITU-T "semi-standard", one used within various standard documents but not a standard in itself. This format was enhanced to allow for multiple tones and volume indications. The basic format is: [volume % ] frequency ':' cadence [ '/' ... ] where frequency is one of frequency single frequency tone freq1 '+' freq2 two frequency juxtaposed (simple mixing) freq1 'x' freq2 first frequency modulated by second frequency freq1 '-' freq2 Alternate frequencies, generated tone is freq1 used for compatibility with tone filters and cadence is mintime ontime '-' offtime [ '-' ontime '-' offtime [ ... ] ] and volume is a percentage of full volume examples: 300:0.25 300Hz for minimum 250ms 1100:0.4-0.4 1100Hz with cadence 400ms on, 400ms off 900-1300:1.5 900Hz for 1.5 seconds 350+440:1 350Hz superimposed with 440Hz (US dial tone) for 1 second 425x15:0.4-0.2-0.4-2 425Hz modulated with 15Hz (Aus ring back tone) with cadence 400ms on, 200ms off, 400ms on, 2s off 425:0.4-0.1/50%425:0.4-0.1 425Hz with cadence 400ms on, 100ms off, 400ms on, 100ms off, where second tone is reduced in volume by 50% A database of tones for all contries in the worls is available at: http://www.3amsystems.com/wireline/tone-search.htm */ class PTones : public PShortArray { PCLASSINFO(PTones, PShortArray) public: enum { MaxVolume = 100, SampleRate = 8000, MaxFrequency = (SampleRate/4), MinFrequency = 30, MinModulation = 5, SineScale = 1000 }; /** Create an empty tone buffer. Tones added will use the specified master volume. */ PTones( unsigned masterVolume = MaxVolume ///< Percentage volume ); /** Create a filled tone buffer using the specified descriptor. */ PTones( const PString & descriptor, ///< Descriptor string for tone(s). See class notes. unsigned masterVolume = MaxVolume ///< Percentage volume ); /** Generate a tone using the specified descriptor. See class general notes for format of the descriptor string. */ bool Generate( const PString & descriptor ///< Descriptor string for tone(s). See class notes. ); /** Generate a tone using the specified values. The operation parameter may be '+', 'x', '-' or ' ' for summing, modulation, pure tone or silence resepctively. The tones duration is always rounded up to the nearest even multiple of the tone cycle to assure correct zero crossing when tones change. */ bool Generate( char operation, unsigned frequency1, ///< Primary frequency for tone unsigned frequency2, ///< Secondary frequency for summing or modulation unsigned milliseconds, ///< Duration of tone unsigned volume = MaxVolume ///< Percentage volume ); protected: bool Juxtapose(unsigned frequency1, unsigned frequency2, unsigned milliseconds, unsigned volume); bool Modulate (unsigned frequency, unsigned modulate, unsigned milliseconds, unsigned volume); bool PureTone (unsigned frequency, unsigned milliseconds, unsigned volume); bool Silence (unsigned milliseconds); unsigned CalcSamples(unsigned milliseconds, unsigned frequency1, unsigned frequency2 = 0); void AddSample(int sample, unsigned volume); unsigned masterVolume; char lastOperation; unsigned lastFrequency1, lastFrequency2; int angle1, angle2; }; /** * this class can be used to generate PCM data for DTMF tones * at a sample rate of 8khz */ class PDTMFEncoder : public PTones { PCLASSINFO(PDTMFEncoder, PTones) public: enum { DefaultToneLen = 100 }; /** * Create PCM data for the specified DTMF sequence */ PDTMFEncoder( const char * dtmf = NULL, ///< character string to encode unsigned milliseconds = DefaultToneLen ///< length of each DTMF tone in milliseconds ); /** * Create PCM data for the specified dtmf key */ PDTMFEncoder( char key, ///< character string to encode unsigned milliseconds = DefaultToneLen ///< length of each DTMF tone in milliseconds ); /** * Add the PCM data for the specified tone sequence to the buffer */ void AddTone( const char * str, ///< string to encode unsigned milliseconds = DefaultToneLen ///< length of DTMF tone in milliseconds ); /** * Add the PCM data for the specified tone to the buffer */ void AddTone( char ch, ///< character to encode unsigned milliseconds = DefaultToneLen ///< length of DTMF tone in milliseconds ); /** * Add the PCM data for the specified dual-frequency tone to the buffer * frequency2 can be zero, which will generate a single frequency tone */ void AddTone( double frequency1, // primary frequency double frequency2 = 0, // secondary frequency, or 0 if no secondary frequency unsigned milliseconds = DefaultToneLen // length of DTMF tone in milliseconds ); /** * Generate PCM data for a single cadence of the US standard ring tone * of 440/480hz for 2 seconds, followed by 5 seconds of silence */ void GenerateRingBackTone() { Generate("440+480:2-4"); } /** * Generate PCM data for 1 second of US standard dial tone * of 350/440hz */ void GenerateDialTone() { Generate("350+440:1"); } /** * Generate PCM data for a single cadence of the US standard busy tone * of 480/620hz for 1/2 second, 1/2 second of silence */ void GenerateBusyTone() { Generate("480+620:0.5-0.5"); } /** * Convenience function to get the ASCII character for a DTMF index, * where the index varies from 0 to 15 * * @returns ASCII value */ char DtmfChar( PINDEX i ///< index of tone ); // Overiding GetSize() screws up the SetSize() }; #endif // PTLIB_DTMF_H // End Of File ///////////////////////////////////////////////////////////////