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2022-10-20 20:29:11 +08:00
commit 4d531f8044
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+/*
+ * iaxclient: a cross-platform IAX softphone library
+ *
+ * Copyrights:
+ * Copyright (C) 2003-2006, Horizon Wimba, Inc.
+ * Copyright (C) 2007, Wimba, Inc.
+ *
+ * Contributors:
+ * Steve Kann <stevek@stevek.com>
+ * Michael Van Donselaar <mvand@vandonselaar.org>
+ * Shawn Lawrence <shawn.lawrence@terracecomm.com>
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU Lesser (Library) General Public License.
+ */
+
+#include "audio_encode.h"
+#include "iaxclient_lib.h"
+#include "iax-client.h"
+#ifdef CODEC_GSM
+#include "codec_gsm.h"
+#endif
+#include "codec_ulaw.h"
+#include "codec_alaw.h"
+
+#include "codec_speex.h"
+#include <speex/speex_preprocess.h>
+
+#ifdef CODEC_ILBC
+#include "codec_ilbc.h"
+#endif
+
+float iaxci_silence_threshold = AUDIO_ENCODE_SILENCE_DB;
+
+static float input_level = 0.0f;
+static float output_level = 0.0f;
+
+static SpeexPreprocessState *st = NULL;
+static int speex_state_size = 0;
+static int speex_state_rate = 0;
+
+int iaxci_filters = IAXC_FILTER_AGC|IAXC_FILTER_DENOISE|IAXC_FILTER_AAGC|IAXC_FILTER_CN;
+
+/* use to measure time since last audio was processed */
+static struct timeval timeLastInput ;
+static struct timeval timeLastOutput ;
+
+static struct iaxc_speex_settings speex_settings =
+{
+	1,    /* decode_enhance */
+	-1,   /* float quality */
+	-1,   /* bitrate */
+	0,    /* vbr */
+	0,    /* abr */
+	3     /* complexity */
+};
+
+
+static float vol_to_db(float vol)
+{
+	/* avoid calling log10() on zero which yields inf or
+	 * negative numbers which yield nan */
+	if ( vol <= 0.0f )
+		return AUDIO_ENCODE_SILENCE_DB;
+	else
+		return log10f(vol) * 20.0f;
+}
+
+static int do_level_callback()
+{
+	static struct timeval last = {0,0};
+	struct timeval now;
+	float input_db;
+	float output_db;
+
+	now = iax_tvnow();
+
+	if ( last.tv_sec != 0 && iaxci_usecdiff(&now, &last) < 100000 )
+		return 0;
+
+	last = now;
+
+	/* if input has not been processed in the last second, set to silent */
+	input_db = iaxci_usecdiff(&now, &timeLastInput) < 1000000 ?
+			vol_to_db(input_level) : AUDIO_ENCODE_SILENCE_DB;
+
+	/* if output has not been processed in the last second, set to silent */
+	output_db = iaxci_usecdiff(&now, &timeLastOutput) < 1000000 ?
+		vol_to_db(output_level) : AUDIO_ENCODE_SILENCE_DB;
+
+	iaxci_do_levels_callback(input_db, output_db);
+
+	return 0;
+}
+
+static void set_speex_filters()
+{
+	int i;
+
+	if ( !st )
+		return;
+
+	i = 1; /* always make VAD decision */
+	speex_preprocess_ctl(st, SPEEX_PREPROCESS_SET_VAD, &i);
+	i = (iaxci_filters & IAXC_FILTER_AGC) ? 1 : 0;
+	speex_preprocess_ctl(st, SPEEX_PREPROCESS_SET_AGC, &i);
+	i = (iaxci_filters & IAXC_FILTER_DENOISE) ? 1 : 0;
+	speex_preprocess_ctl(st, SPEEX_PREPROCESS_SET_DENOISE, &i);
+
+	/*
+	* We can tweak these parameters to play with VAD sensitivity.
+	* For now, we use the default values since it seems they are a good starting point.
+	* However, if need be, this is the code that needs to change
+	*/
+	i = 35;
+	speex_preprocess_ctl(st, SPEEX_PREPROCESS_SET_PROB_START, &i);
+	i = 20;
+	speex_preprocess_ctl(st, SPEEX_PREPROCESS_SET_PROB_CONTINUE, &i);
+}
+
+static void calculate_level(short *audio, int len, float *level)
+{
+	int big_sample = 0;
+	int i;
+
+	for ( i = 0; i < len; i++ )
+	{
+		const int sample = abs(audio[i]);
+		big_sample = sample > big_sample ?
+			sample : big_sample;
+	}
+
+	*level += ((float)big_sample / 32767.0f - *level) / 5.0f;
+}
+
+
+static int input_postprocess(void *audio, int len, int rate)
+{
+	static float lowest_volume = 1.0f;
+	float volume;
+	int silent = 0;
+
+	if ( !st || speex_state_size != len || speex_state_rate != rate )
+	{
+		if (st)
+			speex_preprocess_state_destroy(st);
+		st = speex_preprocess_state_init(len,rate);
+		speex_state_size = len;
+		speex_state_rate = rate;
+		set_speex_filters();
+	}
+
+	calculate_level((short *)audio, len, &input_level);
+
+	/* only preprocess if we're interested in VAD, AGC, or DENOISE */
+	if ( (iaxci_filters & (IAXC_FILTER_DENOISE | IAXC_FILTER_AGC)) ||
+			iaxci_silence_threshold > 0.0f )
+		silent = !speex_preprocess(st, (spx_int16_t *)audio, NULL);
+
+	/* Analog AGC: Bring speex AGC gain out to mixer, with lots of hysteresis */
+	/* use a higher continuation threshold for AAGC than for VAD itself */
+	if ( !silent &&
+	     iaxci_silence_threshold != 0.0f &&
+	     (iaxci_filters & IAXC_FILTER_AGC) &&
+	     (iaxci_filters & IAXC_FILTER_AAGC)
+	   )
+	{
+		static int i = 0;
+
+		i++;
+
+		if ( (i & 0x3f) == 0 )
+		{
+			float loudness;
+#ifdef SPEEX_PREPROCESS_GET_AGC_LOUDNESS
+			speex_preprocess_ctl(st, SPEEX_PREPROCESS_GET_AGC_LOUDNESS, &loudness);
+#else
+			loudness = st->loudness2;
+#endif
+			if ( loudness > 8000.0f || loudness < 4000.0f )
+			{
+				const float level = iaxc_input_level_get();
+
+				if ( loudness > 16000.0f && level > 0.5f )
+				{
+					/* lower quickly if we're really too hot */
+					iaxc_input_level_set(level - 0.2f);
+				}
+				else if ( loudness > 8000.0f && level >= 0.15f )
+				{
+					/* lower less quickly if we're a bit too hot */
+					iaxc_input_level_set(level - 0.1f);
+				}
+				else if ( loudness < 4000.0f && level <= 0.9f )
+				{
+					/* raise slowly if we're cold */
+					iaxc_input_level_set(level + 0.1f);
+				}
+			}
+		}
+	}
+
+	/* This is ugly. Basically just don't get volume level if speex thought
+	 * we were silent. Just set it to 0 in that case */
+	if ( iaxci_silence_threshold > 0.0f && silent )
+		input_level = 0.0f;
+
+	do_level_callback();
+
+	volume = vol_to_db(input_level);
+
+	if ( volume < lowest_volume )
+		lowest_volume = volume;
+
+	if ( iaxci_silence_threshold > 0.0f )
+		return silent;
+	else
+		return volume < iaxci_silence_threshold;
+}
+
+static int output_postprocess(void *audio, int len)
+{
+	calculate_level((short *)audio, len, &output_level);
+
+	do_level_callback();
+
+	return 0;
+}
+
+static struct iaxc_audio_codec *create_codec(int format)
+{
+	switch (format & IAXC_AUDIO_FORMAT_MASK)
+	{
+#ifdef CODEC_GSM
+	case IAXC_FORMAT_GSM:
+		return codec_audio_gsm_new();
+#endif
+	case IAXC_FORMAT_ULAW:
+		return codec_audio_ulaw_new();
+	case IAXC_FORMAT_ALAW:
+		return codec_audio_alaw_new();
+	case IAXC_FORMAT_SPEEX:
+		return codec_audio_speex_new(&speex_settings);
+#ifdef CODEC_ILBC
+	case IAXC_FORMAT_ILBC:
+		return codec_audio_ilbc_new();
+#endif
+	default:
+		/* ERROR: codec not supported */
+		fprintf(stderr, "ERROR: Codec not supported: %d\n", format);
+		return NULL;
+	}
+}
+
+EXPORT void iaxc_set_speex_settings(int decode_enhance, float quality,
+		int bitrate, int vbr, int abr, int complexity)
+{
+	speex_settings.decode_enhance = decode_enhance;
+	speex_settings.quality = quality;
+	speex_settings.bitrate = bitrate;
+	speex_settings.vbr = vbr;
+	speex_settings.abr = abr;
+	speex_settings.complexity = complexity;
+}
+
+int audio_send_encoded_audio(struct iaxc_call *call, int callNo, void *data,
+		int format, int samples)
+{
+	unsigned char outbuf[1024];
+	int outsize = 1024;
+	int silent;
+	int insize = samples;
+
+	/* update last input timestamp */
+	timeLastInput = iax_tvnow();
+
+	silent = input_postprocess(data, insize, 8000);
+
+	if(silent)
+	{
+		if(!call->tx_silent)
+		{  /* send a Comfort Noise Frame */
+			call->tx_silent = 1;
+			if ( iaxci_filters & IAXC_FILTER_CN )
+				iax_send_cng(call->session, 10, NULL, 0);
+		}
+		return 0;  /* poof! no encoding! */
+	}
+
+	/* we're going to send voice now */
+	call->tx_silent = 0;
+
+	/* destroy encoder if it is incorrect type */
+	if(call->encoder && call->encoder->format != format)
+	{
+		call->encoder->destroy(call->encoder);
+		call->encoder = NULL;
+	}
+
+	/* just break early if there's no format defined: this happens for the
+	 * first couple of frames of new calls */
+	if(format == 0) return 0;
+
+	/* create encoder if necessary */
+	if(!call->encoder)
+	{
+		call->encoder = create_codec(format);
+	}
+
+	if(!call->encoder)
+	{
+		/* ERROR: no codec */
+		fprintf(stderr, "ERROR: Codec could not be created: %d\n", format);
+		return 0;
+	}
+
+	if(call->encoder->encode(call->encoder, &insize, (short *)data,
+				&outsize, outbuf))
+	{
+		/* ERROR: codec error */
+		fprintf(stderr, "ERROR: encode error: %d\n", format);
+		return 0;
+	}
+
+	if(samples-insize == 0)
+	{
+		fprintf(stderr, "ERROR encoding (no samples output (samples=%d)\n", samples);
+		return -1;
+	}
+
+	// Send the encoded audio data back to the app if required
+	// TODO: fix the stupid way in which the encoded audio size is returned
+	if ( iaxc_get_audio_prefs() & IAXC_AUDIO_PREF_RECV_LOCAL_ENCODED )
+		iaxci_do_audio_callback(callNo, 0, IAXC_SOURCE_LOCAL, 1,
+				call->encoder->format & IAXC_AUDIO_FORMAT_MASK,
+				sizeof(outbuf) - outsize, outbuf);
+
+	if(iax_send_voice(call->session,format, outbuf,
+				sizeof(outbuf) - outsize, samples-insize) == -1)
+	{
+		fprintf(stderr, "Failed to send voice! %s\n", iax_errstr);
+		return -1;
+	}
+
+	return 0;
+}
+
+/* decode encoded audio; return the number of bytes decoded
+ * negative indicates error */
+int audio_decode_audio(struct iaxc_call * call, void * out, void * data, int len,
+		int format, int * samples)
+{
+	int insize = len;
+	int outsize = *samples;
+
+	timeLastOutput = iax_tvnow();
+
+	if ( format == 0 )
+	{
+		fprintf(stderr, "audio_decode_audio: Format is zero (should't happen)!\n");
+		return -1;
+	}
+
+	/* destroy decoder if it is incorrect type */
+	if ( call->decoder && call->decoder->format != format )
+	{
+		call->decoder->destroy(call->decoder);
+		call->decoder = NULL;
+	}
+
+	/* create decoder if necessary */
+	if ( !call->decoder )
+	{
+		call->decoder = create_codec(format);
+	}
+
+	if ( !call->decoder )
+	{
+		fprintf(stderr, "ERROR: Codec could not be created: %d\n",
+				format);
+		return -1;
+	}
+
+	if ( call->decoder->decode(call->decoder,
+				&insize, (unsigned char *)data,
+				&outsize, (short *)out) )
+	{
+		fprintf(stderr, "ERROR: decode error: %d\n", format);
+		return -1;
+	}
+
+	output_postprocess(out, *samples - outsize);
+
+	*samples = outsize;
+	return len - insize;
+}
+
+EXPORT int iaxc_get_filters(void)
+{
+	return iaxci_filters;
+}
+
+EXPORT void iaxc_set_filters(int filters)
+{
+	iaxci_filters = filters;
+	set_speex_filters();
+}
+
+EXPORT void iaxc_set_silence_threshold(float thr)
+{
+	iaxci_silence_threshold = thr;
+	set_speex_filters();
+}
+