mirror of https://github.com/wb2osz/direwolf.git
213 lines
6.2 KiB
C
213 lines
6.2 KiB
C
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/*------------------------------------------------------------------
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*
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* Module: audio.h
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*
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* Purpose: Interface to audio device commonly called a "sound card."
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*
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*---------------------------------------------------------------*/
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#ifndef AUDIO_H
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#define AUDIO_H 1
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#include "direwolf.h" /* for MAX_CHANS used throughout the application. */
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#include "hdlc_rec2.h" /* for enum retry_e */
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/*
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* PTT control.
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*/
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enum ptt_method_e {
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PTT_METHOD_NONE, /* VOX or no transmit. */
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PTT_METHOD_SERIAL, /* Serial port RTS or DTR. */
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PTT_METHOD_GPIO, /* General purpose I/O, Linux only. */
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PTT_METHOD_LPT }; /* Parallel printer port, Linux only. */
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typedef enum ptt_method_e ptt_method_t;
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enum ptt_line_e { PTT_LINE_RTS = 1, PTT_LINE_DTR = 2 };
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typedef enum ptt_line_e ptt_line_t;
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enum audio_in_type_e {
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AUDIO_IN_TYPE_SOUNDCARD,
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AUDIO_IN_TYPE_SDR_UDP,
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AUDIO_IN_TYPE_STDIN };
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struct audio_s {
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/* Properites of the sound device. */
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char adevice_in[80]; /* Name of the audio input device (or file?). */
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/* TODO: Can be "-" to read from stdin. */
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char adevice_out[80]; /* Name of the audio output device (or file?). */
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int num_channels; /* Should be 1 for mono or 2 for stereo. */
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int samples_per_sec; /* Audio sampling rate. Typically 11025, 22050, or 44100. */
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int bits_per_sample; /* 8 (unsigned char) or 16 (signed short). */
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enum audio_in_type_e audio_in_type;
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/* Where is input (receive) audio coming from? */
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/* Common to all channels. */
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enum retry_e fix_bits; /* Level of effort to recover from */
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/* a bad FCS on the frame. */
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/* Properties for each audio channel, common to receive and transmit. */
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/* Can be different for each radio channel. */
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enum modem_t {AFSK, NONE, SCRAMBLE} modem_type[MAX_CHANS];
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/* Usual AFSK. */
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/* Baseband signal. */
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/* Scrambled http://www.amsat.org/amsat/articles/g3ruh/109/fig03.gif */
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int decimate[MAX_CHANS]; /* Reduce AFSK sample rate by this factor to */
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/* decrease computational requirements. */
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int mark_freq[MAX_CHANS]; /* Two tones for AFSK modulation, in Hz. */
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int space_freq[MAX_CHANS]; /* Standard tones are 1200 and 2200 for 1200 baud. */
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int baud[MAX_CHANS]; /* Data bits (more accurately, symbols) per second. */
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/* Standard rates are 1200 for VHF and 300 for HF. */
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char profiles[MAX_CHANS][16]; /* 1 or more of ABC etc. */
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int num_freq[MAX_CHANS]; /* Number of different frequency pairs for decoders. */
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int offset[MAX_CHANS]; /* Spacing between filter frequencies. */
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int num_subchan[MAX_CHANS]; /* Total number of modems / hdlc decoders for each channel. */
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/* Potentially it could be product of strlen(profiles) * num_freq. */
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/* Currently can't use both at once. */
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/* Additional properties for transmit. */
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ptt_method_t ptt_method[MAX_CHANS]; /* serial port or GPIO. */
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char ptt_device[MAX_CHANS][20]; /* Serial device name for PTT. e.g. COM1 or /dev/ttyS0 */
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ptt_line_t ptt_line[MAX_CHANS]; /* Control line wehn using serial port. */
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/* PTT_RTS, PTT_DTR. */
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int ptt_gpio[MAX_CHANS]; /* GPIO number. */
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int ptt_lpt_bit[MAX_CHANS]; /* Bit number for parallel printer port. */
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/* Bit 0 = pin 2, ..., bit 7 = pin 9. */
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int ptt_invert[MAX_CHANS]; /* Invert the output. */
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int slottime[MAX_CHANS]; /* Slot time in 10 mS units for persistance algorithm. */
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/* Typical value is 10 meaning 100 milliseconds. */
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int persist[MAX_CHANS]; /* Sets probability for transmitting after each */
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/* slot time delay. Transmit if a random number */
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/* in range of 0 - 255 <= persist value. */
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/* Otherwise wait another slot time and try again. */
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/* Default value is 63 for 25% probability. */
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int txdelay[MAX_CHANS]; /* After turning on the transmitter, */
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/* send "flags" for txdelay * 10 mS. */
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/* Default value is 30 meaning 300 milliseconds. */
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int txtail[MAX_CHANS]; /* Amount of time to keep transmitting after we */
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/* are done sending the data. This is to avoid */
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/* dropping PTT too soon and chopping off the end */
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/* of the frame. Again 10 mS units. */
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/* At this point, I'm thinking of 10 as the default. */
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};
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#if __WIN32__
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#define DEFAULT_ADEVICE "" /* Windows: Empty string = default audio device. */
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#else
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#if USE_ALSA
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#define DEFAULT_ADEVICE "default" /* Use default device for ALSA. */
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#else
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#define DEFAULT_ADEVICE "/dev/dsp" /* First audio device for OSS. */
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#endif
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#endif
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/*
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* UDP audio receiving port. Couldn't find any standard or usage precedent.
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* Got the number from this example: http://gqrx.dk/doc/streaming-audio-over-udp
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* Any better suggestions?
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*/
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#define DEFAULT_UDP_AUDIO_PORT 7355
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// Maximum size of the UDP buffer (for allowing IP routing, udp packets are often limited to 1472 bytes)
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#define SDR_UDP_BUF_MAXLEN 2000
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#define DEFAULT_NUM_CHANNELS 1
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#define DEFAULT_SAMPLES_PER_SEC 44100 /* Very early observations. Might no longer be valid. */
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/* 22050 works a lot better than 11025. */
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/* 44100 works a little better than 22050. */
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/* If you have a reasonable machine, use the highest rate. */
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#define MIN_SAMPLES_PER_SEC 8000
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#define MAX_SAMPLES_PER_SEC 48000 /* Formerly 44100. */
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/* Software defined radio often uses 48000. */
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#define DEFAULT_BITS_PER_SAMPLE 16
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#define DEFAULT_FIX_BITS RETRY_SWAP_SINGLE
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/*
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* Standard for AFSK on VHF FM.
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* Reversing mark and space makes no difference because
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* NRZI encoding only cares about change or lack of change
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* between the two tones.
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*
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* HF SSB uses 300 baud and 200 Hz shift.
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* 1600 & 1800 Hz is a popular tone pair, sometimes
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* called the KAM tones.
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*/
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#define DEFAULT_MARK_FREQ 1200
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#define DEFAULT_SPACE_FREQ 2200
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#define DEFAULT_BAUD 1200
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/*
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* Typical transmit timings for VHF.
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*/
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#define DEFAULT_SLOTTIME 10
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#define DEFAULT_PERSIST 63
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#define DEFAULT_TXDELAY 30
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#define DEFAULT_TXTAIL 10 /* not sure yet. */
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/*
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* Note that we have two versions of these in audio.c and audio_win.c.
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* Use one or the other depending on the platform.
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*/
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int audio_open (struct audio_s *pa);
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int audio_get (void);
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int audio_put (int c);
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int audio_flush (void);
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int audio_wait (int duration);
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int audio_close (void);
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#endif /* ifdef AUDIO_H */
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/* end audio.h */
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