codecs: Add iLBC 20.

Asterisk already supported iLBC 30. This change adds iLBC 20. Now, Asterisk
defaults to iLBC 20 but falls back to iLBC 30, when the remote party requests
this.

ASTERISK-26218 #close
ASTERISK-26221 #close
Reported by: Aaron Meriwether

Change-Id: I07f523a3aa1338bb5217a1bf69c1eeb92adedffa

2 files changed, 55 insertions, 31 deletions

diff --git a/codecs/codec_ilbc.c b/codecs/codec_ilbc.c
index 3e480e8fd..fc713beb7 100644
--- a/codecs/codec_ilbc.c
+++ b/codecs/codec_ilbc.c
@@ -34,10 +34,13 @@
 
 ASTERISK_REGISTER_FILE()
 
-#include "asterisk/translate.h"
+#include "asterisk/codec.h"             /* for AST_MEDIA_TYPE_AUDIO */
+#include "asterisk/format.h"            /* for ast_format_get_attribute_data */
+#include "asterisk/frame.h"             /* for ast_frame, etc */
+#include "asterisk/linkedlists.h"       /* for AST_LIST_NEXT, etc */
+#include "asterisk/logger.h"            /* for ast_log, ast_debug, etc */
 #include "asterisk/module.h"
-#include "asterisk/utils.h"
-#include "asterisk/linkedlists.h"
+#include "asterisk/translate.h"         /* for ast_trans_pvt, etc */
 
 #ifdef ILBC_WEBRTC
 #include <ilbc.h>
@@ -52,13 +55,10 @@ typedef float         ilbc_block;
 #define BUF_TYPE uc
 #endif
 
-#define USE_ILBC_ENHANCER	0
-#define ILBC_MS 			30
-/* #define ILBC_MS			20 */
+#include "asterisk/ilbc.h"
 
-#define	ILBC_FRAME_LEN	50	/* apparently... */
-#define	ILBC_SAMPLES	240	/* 30ms at 8000 hz */
-#define	BUFFER_SAMPLES	8000
+#define USE_ILBC_ENHANCER 0
+#define BUFFER_SAMPLES    8000
 
 /* Sample frame data */
 #include "asterisk/slin.h"
@@ -69,13 +69,16 @@ struct ilbc_coder_pvt {
 	iLBC_Dec_Inst_t dec;
 	/* Enough to store a full second */
 	int16_t buf[BUFFER_SAMPLES];
+	int16_t inited;
 };
 
 static int lintoilbc_new(struct ast_trans_pvt *pvt)
 {
 	struct ilbc_coder_pvt *tmp = pvt->pvt;
+	struct ilbc_attr *attr = pvt->explicit_dst ? ast_format_get_attribute_data(pvt->explicit_dst) : NULL;
+	const unsigned int mode = attr ? attr->mode : 30;
 
-	initEncode(&tmp->enc, ILBC_MS);
+	initEncode(&tmp->enc, mode);
 
 	return 0;
 }
@@ -84,7 +87,7 @@ static int ilbctolin_new(struct ast_trans_pvt *pvt)
 {
 	struct ilbc_coder_pvt *tmp = pvt->pvt;
 
-	initDecode(&tmp->dec, ILBC_MS, USE_ILBC_ENHANCER);
+	tmp->inited = 0; /* we do not know the iLBC mode, yet */
 
 	return 0;
 }
@@ -93,13 +96,19 @@ static int ilbctolin_new(struct ast_trans_pvt *pvt)
 static int ilbctolin_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
 {
 	struct ilbc_coder_pvt *tmp = pvt->pvt;
+	struct ilbc_attr *attr = ast_format_get_attribute_data(f->subclass.format);
+	const unsigned int mode = attr ? attr->mode : 30;
+	const unsigned int sample_rate = pvt->t->dst_codec.sample_rate;
+	const unsigned int samples_per_frame = mode * sample_rate / 1000;
+	const unsigned int octets_per_frame = (mode == 20) ? 38 : 50;
+
 	int plc_mode = 1; /* 1 = normal data, 0 = plc */
 	/* Assuming there's space left, decode into the current buffer at
 	   the tail location.  Read in as many frames as there are */
 	int x,i;
 	int datalen = f->datalen;
 	int16_t *dst = pvt->outbuf.i16;
-	ilbc_block tmpf[ILBC_SAMPLES];
+	ilbc_block tmpf[samples_per_frame];
 
 	if (!f->data.ptr && datalen) {
 		ast_debug(1, "issue 16070, ILIB ERROR. data = NULL datalen = %d src = %s\n", datalen, f->src ? f->src : "no src set");
@@ -108,27 +117,32 @@ static int ilbctolin_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
 	}
 
 	if (datalen == 0) { /* native PLC, set fake datalen and clear plc_mode */
-		datalen = ILBC_FRAME_LEN;
-		f->samples = ILBC_SAMPLES;
+		datalen = octets_per_frame;
+		f->samples = samples_per_frame;
 		plc_mode = 0;	/* do native plc */
-		pvt->samples += ILBC_SAMPLES;
+		pvt->samples += samples_per_frame;
 	}
 
-	if (datalen % ILBC_FRAME_LEN) {
-		ast_log(LOG_WARNING, "Huh?  An ilbc frame that isn't a multiple of 50 bytes long from %s (%d)?\n", f->src, datalen);
+	if (datalen % octets_per_frame) {
+		ast_log(LOG_WARNING, "Huh?  An ilbc frame that isn't a multiple of %u bytes long from %s (%d)?\n", octets_per_frame, f->src, datalen);
 		return -1;
 	}
 
-	for (x=0; x < datalen ; x += ILBC_FRAME_LEN) {
-		if (pvt->samples + ILBC_SAMPLES > BUFFER_SAMPLES) {
+	if (!tmp->inited) {
+		initDecode(&tmp->dec, mode, USE_ILBC_ENHANCER);
+		tmp->inited = 1;
+	}
+
+	for (x = 0; x < datalen; x += octets_per_frame) {
+		if (pvt->samples + samples_per_frame > BUFFER_SAMPLES) {
 			ast_log(LOG_WARNING, "Out of buffer space\n");
 			return -1;
 		}
 		iLBC_decode(tmpf, plc_mode ? f->data.ptr + x : NULL, &tmp->dec, plc_mode);
-		for ( i=0; i < ILBC_SAMPLES; i++)
+		for (i = 0; i < samples_per_frame; i++)
 			dst[pvt->samples + i] = tmpf[i];
-		pvt->samples += ILBC_SAMPLES;
-		pvt->datalen += 2*ILBC_SAMPLES;
+		pvt->samples += samples_per_frame;
+		pvt->datalen += samples_per_frame * 2;
 	}
 	return 0;
 }
@@ -155,20 +169,26 @@ static struct ast_frame *lintoilbc_frameout(struct ast_trans_pvt *pvt)
 	struct ast_frame *last = NULL;
 	int samples = 0; /* output samples */
 
-	while (pvt->samples >= ILBC_SAMPLES) {
+	struct ilbc_attr *attr = ast_format_get_attribute_data(pvt->f.subclass.format);
+	const unsigned int mode = attr ? attr->mode : 30;
+	const unsigned int sample_rate = pvt->t->dst_codec.sample_rate;
+	const unsigned int samples_per_frame = mode * sample_rate / 1000;
+	const unsigned int octets_per_frame = (mode == 20) ? 38 : 50;
+
+	while (pvt->samples >= samples_per_frame) {
 		struct ast_frame *current;
-		ilbc_block tmpf[ILBC_SAMPLES];
+		ilbc_block tmpf[samples_per_frame];
 		int i;
 
 		/* Encode a frame of data */
-		for (i = 0 ; i < ILBC_SAMPLES ; i++)
+		for (i = 0; i < samples_per_frame; i++)
 			tmpf[i] = tmp->buf[samples + i];
 		iLBC_encode((ilbc_bytes *) pvt->outbuf.BUF_TYPE, tmpf, &tmp->enc);
 
-		samples += ILBC_SAMPLES;
-		pvt->samples -= ILBC_SAMPLES;
+		samples += samples_per_frame;
+		pvt->samples -= samples_per_frame;
 
-		current = ast_trans_frameout(pvt, ILBC_FRAME_LEN, ILBC_SAMPLES);
+		current = ast_trans_frameout(pvt, octets_per_frame, samples_per_frame);
 		if (!current) {
 			continue;
 		} else if (last) {
@@ -226,7 +246,8 @@ static struct ast_translator lintoilbc = {
 	.frameout = lintoilbc_frameout,
 	.sample = slin8_sample,
 	.desc_size = sizeof(struct ilbc_coder_pvt),
-	.buf_size = (BUFFER_SAMPLES * ILBC_FRAME_LEN + ILBC_SAMPLES - 1) / ILBC_SAMPLES,
+	/* frame len (38 bytes), frame size (160 samples), ceil (+ 160 - 1) */
+	.buf_size = (BUFFER_SAMPLES * 38 + 160 - 1) / 160,
 };
 
 static int unload_module(void)
diff --git a/codecs/ex_ilbc.h b/codecs/ex_ilbc.h
index 3a79b0918..3fe2749dd 100644
--- a/codecs/ex_ilbc.h
+++ b/codecs/ex_ilbc.h
@@ -7,6 +7,9 @@
  *
  */
 
+#include "asterisk/format_cache.h"      /* for ast_format_ilbc */
+#include "asterisk/frame.h"             /* for ast_frame, etc */
+
 static uint8_t ex_ilbc[] = {
 	0xff, 0xa0, 0xff, 0xfa, 0x0f, 0x60, 0x12, 0x11, 0xa2, 0x47, 
 	0x22, 0x8c, 0x00, 0x00, 0x01, 0x02, 0x80, 0x43, 0xa0, 0x40, 
@@ -20,8 +23,8 @@ static struct ast_frame *ilbc_sample(void)
 	static struct ast_frame f = {
 		.frametype = AST_FRAME_VOICE,
 		.datalen = sizeof(ex_ilbc),
-		/* All frames are 30 ms long */
-		.samples = ILBC_SAMPLES,
+		/* example frames are default long (30 ms) */
+		.samples = 240,
 		.mallocd = 0,
 		.offset = 0,
 		.src = __PRETTY_FUNCTION__,