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osmo-cc-pstn-endpoint
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Audio rework, new jitter buffer 

Jitter buffer is now based on packets, not on samples. The frames are
dejittered in received form. After reading from jitter buffer, they are
decoded in correct order. If a frame is missing, it is concealed by
repeating audio.
This commit is contained in:
Andreas Eversberg 2024-03-24 10:13:58 +01:00
parent e9b0e9481c
commit d49008d2ea
6 changed files with 447 additions and 275 deletions
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2
configure.ac
View File

@ -78,7 +78,7 @@ AC_CHECK_LIB([m], [main])
AC_CHECK_LIB([pthread], [main])
PKG_CHECK_MODULES(LIBOSMOCORE, libosmocore >= 1.9.0)
PKG_CHECK_MODULES(LIBOSMOCC, libosmocc >= 1.0.0)
PKG_CHECK_MODULES(LIBOSMOCC, libosmocc >= 2.0.0)
AC_OUTPUT(
src/liboptions/Makefile

593
src/libjitter/jitter.c
View File

@ -21,12 +21,13 @@
*
* Storing:
*
* Each saved frame is sorted into the list of packages by their sequence
* number.
* Each saved frame is sorted into the list of packages by their timestamp.
*
* The first packet will be stored with a delay of minimum jitter window size.
* The first packet will be stored with a timestamp offset of minimum jitter
* window size or half of the target size, depending on the adaptive jitter
* buffer flag.
*
* Packets with the same sequence are dropped.
* Packets with the same timestamp are dropped.
*
* Early packts that exceed maximum jitter window size cause jitter
* window to shift into the future.
@ -35,37 +36,36 @@
* delay). Minimum jitter window size is added also, to prevent subsequent
* packets from beeing late too.
*
* If no sequence is provided (autosequence), the sequence number is generated
* by a counter. Also the timestamp is generated by counting the length of each
* frame.
* If adaptive jitter buffer is used, a delay that exceed the target size
* is reduced to the target size.
*
* If ssrc changes, the buffer is reset.
* If ssrc changes, the buffer is reset, but not locked again.
*
*
* Playout:
* Loading:
*
* The caller of the playout function can request any length of samples from
* the packet list. The packt's time stamp and the jitter window time stamp
* indicate what portion of a packet is already provided to the caller.
* Complete packet, sent to the caller, are removed.
* jitter_offset() will return the number of samples between the jitter buffer's head and the first packet afterwards. Packets that already passed the jitter buffer's head are ignored. If no frame is ahead the jitter buffer's head, a negative value is returned.
*
* Missing packets are interpolated by repeating last 20ms of audio (optional)
* or by inserting zeroes (sample size > 1 byte) or by inserting 0xff (sample
* size = 1). In case of repeating audio, the number of turns are limited until
* buffer is reset to silence, if no frames are received for a certain time.
* jitter_load() will remove and return the frame at the jitter buffer's head. Packet that already passed the jitter buffer's head are deleted. If no frame matches the jitter buffer's head, NULL is returned.
*
* Optionally the constant delay will be measured continuously and lowered if
* greater than minimum window size. (adaptive jitter buffer size)
* jitter_advance() will advance the jitter buffer's head by the given number of samples.
*
* Note that the delay is measured with time stamp of frame, no matter what
* the length is. Length is an extra delay, but not considered here.
* jitter_load_samples() will read decoded samples from jitter buffer's frames.
* This means that that the decoder of each frame must generate samples of equal type and size.
* If there is a gap between jitter buffer's head and the next frame, the samples are taken from the last frame.
* The conceal function is called in this case, to extrapolate the missing samples.
* If no conceal function is given, the last frame is repeated.
* If there is no gap between jitter buffer's head and the next frame, the frame is decoded and the samples are taken from that frame.
* After that the jitter buffer's head is advanced by the number of samples read.
*
* *TBD*
*
*
* Unlocking:
*
* If the buffer is created or reset, the buffer is locked, so no packets are
* stored. When the playout routine is called, the buffer is unlocked. This
* prevents from filling the buffer before playout is performed, which would
* stored. When the loading routine is called, the buffer is unlocked. This
* prevents from filling the buffer before loading is performed, which would
* cause high delay.
*
*/
@ -82,33 +82,19 @@
#define INITIAL_DELAY_INTERVAL 0.5
#define REPEAT_DELAY_INTERVAL 3.0
#define EXTRA_BUFFER 0.020 // 20 ms
#define EXTRA_TIMEOUT 0.100 // maximum time to repeat extrapolation buffer
/* uncomment to enable heavy debugging */
//#define HEAVY_DEBUG
//#define VISUAL_DEBUG
static int unnamed_count = 1;
/* create jitter buffer */
int jitter_create(jitter_t *jb, const char *name, double samplerate, int sample_size, double target_window_duration, double max_window_duration, uint32_t window_flags)
int jitter_create(jitter_t *jb, const char *name, double samplerate, double target_window_duration, double max_window_duration, uint32_t window_flags)
{
int rc = 0;
memset(jb, 0, sizeof(*jb));
jb->sample_duration = 1.0 / samplerate;
jb->sample_size = sample_size;
jb->target_window_size = (int)(samplerate * target_window_duration);
jb->max_window_size = (int)(samplerate * max_window_duration);
jb->window_flags = window_flags;
jb->extra_size = (int)(EXTRA_BUFFER * samplerate);
jb->extra_samples = calloc(sample_size, jb->extra_size);
if (!jb->extra_samples) {
LOGP(DJITTER, LOGL_ERROR, "No memory for frame.\n");
rc = -ENOMEM;
goto error;
}
jb->extra_timeout_max = (int)ceil(EXTRA_TIMEOUT / EXTRA_BUFFER);
memset(jb, 0, sizeof(*jb));
/* optionally give a string to be show with the debug */
if (name && *name)
@ -116,36 +102,37 @@ int jitter_create(jitter_t *jb, const char *name, double samplerate, int sample_
else
snprintf(jb->name, sizeof(jb->name) - 1, "(unnamed %d) ", unnamed_count++);
jb->sample_duration = 1.0 / samplerate;
jb->samples_20ms = samplerate / 50;
jb->target_window_size = (int)ceil(target_window_duration / jb->sample_duration);
jb->max_window_size = (int)ceil(max_window_duration / jb->sample_duration);
jb->window_flags = window_flags;
jitter_reset(jb);
LOGP(DJITTER, LOGL_INFO, "%sCreated jitter buffer. (samplerate=%.0f, target_window=%.0fms, max_window=%.0fms, flag:latency=%s flag:repeat=%s)\n", jb->name, samplerate, target_window_duration * 1000.0, max_window_duration * 1000.0, (window_flags & JITTER_FLAG_LATENCY) ? "true" : "false", (window_flags & JITTER_FLAG_REPEAT) ? "true" : "false");
LOGP(DJITTER, LOGL_INFO, "%s Created jitter buffer. (samperate=%.0f, target_window=%.0fms, max_window=%.0fms, flag:latency=%s flag:repeat=%s)\n",
jb->name,
samplerate,
(double)jb->target_window_size * jb->sample_duration * 1000.0,
(double)jb->max_window_size * jb->sample_duration * 1000.0,
(window_flags & JITTER_FLAG_LATENCY) ? "true" : "false",
(window_flags & JITTER_FLAG_REPEAT) ? "true" : "false");
error:
if (rc)
jitter_destroy(jb);
return rc;
}
static void clear_extra_buffer(jitter_t *jb)
{
if (jb->sample_size == 1)
memset(jb->extra_samples, 0xff, jb->sample_size * jb->extra_size);
else
memset(jb->extra_samples, 0, jb->sample_size * jb->extra_size);
}
/* reset jitter buffer */
void jitter_reset(jitter_t *jb)
{
jitter_frame_t *jf, *temp;
LOGP(DJITTER, LOGL_INFO, "%sReset jitter buffer.\n", jb->name);
LOGP(DJITTER, LOGL_INFO, "%s Reset jitter buffer.\n", jb->name);
/* jitter buffer locked */
jb->unlocked = 0;
jb->unlocked = false;
/* window becomes invalid */
jb->window_valid = 0;
jb->window_valid = false;
/* remove all pending frames */
jf = jb->frame_list;
@ -156,269 +143,403 @@ void jitter_reset(jitter_t *jb)
}
jb->frame_list = NULL;
/* clear extrapolation buffer */
if (jb->extra_samples)
clear_extra_buffer(jb);
jb->extra_index = 0;
jb->extra_timeout_count = jb->extra_timeout_max; /* no data in buffer yet, so we set timeout condition */
/* delay measurement and reduction */
jb->delay_counter = 0.0;
jb->delay_interval = INITIAL_DELAY_INTERVAL;
jb->min_delay_value = -1;
/* remove current sample buffer */
free(jb->spl_buf);
jb->spl_buf = NULL;
jb->spl_valid = false;
}
void jitter_destroy(jitter_t *jb)
{
jitter_reset(jb);
LOGP(DJITTER, LOGL_INFO, "%sDestroying jitter buffer.\n", jb->name);
if (jb->extra_samples) {
free(jb->extra_samples);
jb->extra_samples = NULL;
}
LOGP(DJITTER, LOGL_INFO, "%s Destroying jitter buffer.\n", jb->name);
}
/* store audio in jitterbuffer
*
* stop if buffer is completely filled
*/
void jitter_save(jitter_t *jb, void *samples, int length, int has_sequence, uint16_t sequence, uint32_t timestamp, uint32_t ssrc)
jitter_frame_t *jitter_frame_alloc(void (*decoder)(uint8_t *src_data, int src_len, uint8_t **dst_data, int *dst_len, void *priv), void *decoder_priv, uint8_t *data, int size, uint8_t marker, uint16_t sequence, uint32_t timestamp, uint32_t ssrc)
{
jitter_frame_t *jf, **jfp;
int16_t offset_sequence;
jitter_frame_t *jf;
jf = malloc(sizeof(*jf) + size);
if (!jf) {
LOGP(DJITTER, LOGL_ERROR, "No memory for frame.\n");
return NULL;
}
memset(jf, 0, sizeof(*jf)); // note: clear header only
jf->decoder = decoder;
jf->decoder_priv = decoder_priv;
memcpy(jf->data, data, size);
jf->size = size;
jf->marker = marker;
jf->sequence = sequence;
jf->timestamp = timestamp;
jf->ssrc = ssrc;
return jf;
}
void jitter_frame_free(jitter_frame_t *jf)
{
free(jf);
}
void jitter_frame_get(jitter_frame_t *jf, void (**decoder)(uint8_t *src_data, int src_len, uint8_t **dst_data, int *dst_len, void *priv), void **decoder_priv, uint8_t **data, int *size, uint8_t *marker, uint16_t *sequence, uint32_t *timestamp, uint32_t *ssrc)
{
if (decoder)
*decoder = jf->decoder;
if (decoder_priv)
*decoder_priv = jf->decoder_priv;
if (data)
*data = jf->data;
if (size)
*size = jf->size;
if (marker)
*marker = jf->marker;
if (sequence)
*sequence = jf->sequence;
if (timestamp)
*timestamp = jf->timestamp;
if (ssrc)
*ssrc = jf->ssrc;
}
/* Store frame in jitterbuffer
*
* Use sequence number to order frames.
* Use timestamp to handle delay.
*/
void jitter_save(jitter_t *jb, jitter_frame_t *jf)
{
jitter_frame_t **jfp;
int32_t offset_timestamp;
/* ignore frames until the buffer is unlocked by jitter_load() */
if (!jb->unlocked)
if (!jb->unlocked) {
jitter_frame_free(jf);
return;
/* omit frames with no data */
if (length < 1)
return;
/* generate sequence and timestamp automatically, if enabled */
if (!has_sequence) {
#ifdef DEBUG_JITTER
LOGP(DJITTER, LOGL_DEBUG, "%sSave frame of %d samples (no seqence).\n", jb->name, length);
#endif
sequence = jb->next_sequence;
jb->next_sequence++;
timestamp = jb->next_timestamp;
jb->next_timestamp += length;
ssrc = jb->window_ssrc;
} else {
#ifdef HEAVY_DEBUG
LOGP(DJITTER, LOGL_DEBUG, "%sSave frame of %d samples (seqence=%u timestamp=%u ssrc=0x%02x).\n", jb->name, length, sequence, timestamp, ssrc);
#endif
jb->next_sequence = sequence + 1;
jb->next_timestamp = timestamp + length;
}
/* first packet (with this ssrc) sets window size to target_window_size */
if (!jb->window_valid || jb->window_ssrc != ssrc) {
if (!jb->window_valid || jb->window_ssrc != jf->ssrc) {
if (!jb->window_valid)
LOGP(DJITTER, LOGL_DEBUG, "%s Initial frame after init or reset.\n", jb->name);
else
LOGP(DJITTER, LOGL_DEBUG, "%s SSRC changed.\n", jb->name);
// NOTE: Reset must be called before finding the frame location below, because there will be no frame in list anymore!
jitter_reset(jb);
jb->unlocked = 1;
jb->unlocked = true;
/* when using dynamic jitter buffer, we use half of the target delay */
if ((jb->window_flags & JITTER_FLAG_LATENCY)) {
jb->window_timestamp = timestamp - (uint32_t)jb->target_window_size / 2;
jb->window_timestamp = jf->timestamp - (uint32_t)jb->target_window_size / 2;
} else {
jb->window_timestamp = timestamp - (uint32_t)jb->target_window_size;
jb->window_timestamp = jf->timestamp - (uint32_t)jb->target_window_size;
}
jb->window_valid = 1;
jb->window_ssrc = ssrc;
jb->window_valid = true;
jb->window_ssrc = jf->ssrc;
jb->min_delay = -1;
jb->delay_counter = 0.0;
jb->delay_interval = INITIAL_DELAY_INTERVAL;
}
/* reduce delay */
if (jb->delay_counter >= jb->delay_interval) {
if (jb->min_delay >= 0)
LOGP(DJITTER, LOGL_DEBUG, "%s Statistics: target_window_delay=%.0fms max_window_delay=%.0fms current min_delay=%.0fms\n",
jb->name,
(double)jb->target_window_size * jb->sample_duration * 1000.0,
(double)jb->max_window_size * jb->sample_duration * 1000.0,
(double)jb->min_delay * jb->sample_duration * 1000.0);
/* delay reduction, if minimum delay is greater than target jitter window size */
if ((jb->window_flags & JITTER_FLAG_LATENCY) && jb->min_delay > jb->target_window_size) {
LOGP(DJITTER, LOGL_DEBUG, "%s Reducing current minimum delay of %.0fms, because maximum delay is greater than target window size of %.0fms.\n",
jb->name,
(double)jb->min_delay * jb->sample_duration * 1000.0,
(double)jb->target_window_size * jb->sample_duration * 1000.0);
/* only reduce delay to half of the target window size */
jb->window_timestamp += jb->min_delay - jb->target_window_size / 2;
}
jb->delay_counter -= jb->delay_interval;
jb->delay_interval = REPEAT_DELAY_INTERVAL;
jb->min_delay = -1;
}
/* find location where to put frame into the list, depending on sequence number */
jfp = &jb->frame_list;
while(*jfp) {
offset_sequence = (int16_t)(sequence - (*jfp)->sequence);
offset_timestamp = (int16_t)(jf->timestamp - (*jfp)->timestamp);
/* found double entry */
if (offset_sequence == 0) {
LOGP(DJITTER, LOGL_DEBUG, "%s Dropping double packet (sequence = %d)\n", jb->name, sequence);
if (offset_timestamp == 0) {
LOGP(DJITTER, LOGL_DEBUG, "%s Dropping double packet (timestamp = %u)\n", jb->name, jf->timestamp);
jitter_frame_free(jf);
return;
}
/* offset is negative, so we found the position to insert frame */
if (offset_sequence < 0)
if (offset_timestamp < 0)
break;
jfp = &((*jfp)->next);
}
offset_timestamp = timestamp - jb->window_timestamp;
offset_timestamp = jf->timestamp - jb->window_timestamp;
#ifdef HEAVY_DEBUG
LOGP(DJITTER, LOGL_DEBUG, "%sFrame has offset of %.0fms in jitter buffer.\n", jb->name, (double)offset_timestamp * jb->sample_duration * 1000.0);
LOGP(DJITTER, LOGL_DEBUG, "%s Frame has offset of %.0fms in jitter buffer.\n", jb->name, (double)offset_timestamp * jb->sample_duration * 1000.0);
#endif
/* measure delay */
if (jb->min_delay_value < 0 || offset_timestamp < jb->min_delay_value)
jb->min_delay_value = offset_timestamp;
if (jb->min_delay < 0 || offset_timestamp < jb->min_delay)
jb->min_delay = offset_timestamp;
/* if frame is too early (delay ceases), shift window to the future */
if (offset_timestamp > jb->max_window_size) {
if ((jb->window_flags & JITTER_FLAG_LATENCY)) {
LOGP(DJITTER, LOGL_DEBUG, "%s Frame too early: Shift jitter buffer to the future, to make the frame fit to the end. (offset_timestamp(%d) > max_window_size(%d))\n", jb->name, offset_timestamp, jb->max_window_size);
LOGP(DJITTER, LOGL_DEBUG, "%s Frame too early: Shift jitter buffer to the future, to make the frame fit to the end. (offset_sequence(%d) > max_window_size(%d))\n", jb->name, offset_timestamp, jb->max_window_size);
/* shift window so it fits to the end of window */
jb->window_timestamp = timestamp - jb->max_window_size;
jb->window_timestamp = jf->timestamp - jb->max_window_size;
jb->min_delay = -1;
jb->delay_counter = 0.0;
jb->delay_interval = REPEAT_DELAY_INTERVAL;
} else {
LOGP(DJITTER, LOGL_DEBUG, "%s Frame too early: Shift jitter buffer to the future, to make the frame fit to the target delay. (offset_timestamp(%d) > max_window_size(%d))\n", jb->name, offset_timestamp, jb->max_window_size);
LOGP(DJITTER, LOGL_DEBUG, "%s Frame too early: Shift jitter buffer to the future, to make the frame fit to the target delay. (offset_sequence(%d) > max_window_size(%d))\n", jb->name, offset_timestamp, jb->max_window_size);
/* shift window so frame fits to the start of window + target delay */
jb->window_timestamp = timestamp - (uint32_t)(jb->target_window_size);
jb->window_timestamp = jf->timestamp - jb->target_window_size;
jb->min_delay = -1;
jb->delay_counter = 0.0;
jb->delay_interval = REPEAT_DELAY_INTERVAL;
}
}
/* is frame is too late, shift window to the past. */
if (offset_timestamp < 0) {
if ((jb->window_flags & JITTER_FLAG_LATENCY)) {
LOGP(DJITTER, LOGL_DEBUG, "%s Frame too late: Shift jitter buffer to the past, and add target window size. (offset_timestamp(%d) < 0)\n", jb->name, offset_timestamp);
LOGP(DJITTER, LOGL_DEBUG, "%s Frame too late: Shift jitter buffer to the past, and add target window size. (offset_sequence(%d) < 0)\n", jb->name, offset_timestamp);
/* shift window so frame fits to the start of window + half of target delay */
jb->window_timestamp = timestamp - (uint32_t)(jb->target_window_size) / 2;
jb->window_timestamp = jf->timestamp - jb->target_window_size / 2;
jb->min_delay = -1;
jb->delay_counter = 0.0;
jb->delay_interval = REPEAT_DELAY_INTERVAL;
} else {
LOGP(DJITTER, LOGL_DEBUG, "%s Frame too late: Shift jitter buffer to the past, and add half target window size. (offset_timestamp(%d) < 0)\n", jb->name, offset_timestamp);
LOGP(DJITTER, LOGL_DEBUG, "%s Frame too late: Shift jitter buffer to the past, and add half target window size. (offset_sequence(%d) < 0)\n", jb->name, offset_timestamp);
/* shift window so frame fits to the start of window + target delay */
jb->window_timestamp = timestamp - (uint32_t)(jb->target_window_size);
jb->window_timestamp = jf->timestamp - jb->target_window_size;
jb->min_delay = -1;
jb->delay_counter = 0.0;
jb->delay_interval = REPEAT_DELAY_INTERVAL;
}
}
/* insert or append frame */
#ifdef HEAVY_DEBUG
LOGP(DJITTER, LOGL_DEBUG, "%s Store frame\n", jb->name);
#include <time.h>
static struct timespec tv;
clock_gettime(CLOCK_REALTIME, &tv);
LOGP(DJITTER, LOGL_DEBUG, "%s Store frame. %ld.%04ld\n", jb->name, tv.tv_sec, tv.tv_nsec / 1000000);
#endif
jf = malloc(sizeof(*jf) + length * jb->sample_size);
if (!jf) {
LOGP(DJITTER, LOGL_ERROR, "No memory for frame.\n");
return;
}
memset(jf, 0, sizeof(*jf)); // note: clear header only
jf->sequence = sequence;
jf->timestamp = timestamp;
memcpy(jf->samples, samples, length * jb->sample_size);
jf->length = length;
jf->next = *jfp;
*jfp = jf;
}
/* get audio from jitterbuffer
*/
void jitter_load(jitter_t *jb, void *samples, int length)
/* get offset to next chunk, return -1, if there is no */
int32_t jitter_offset(jitter_t *jb)
{
jitter_frame_t *jf;
int32_t count, count2, index;
int16_t offset_timestamp = 0;
/* now unlock jitter buffer */
jb->unlocked = true;
/* get timestamp of chunk that is not in the past */
for (jf = jb->frame_list; jf; jf = jf->next) {
offset_timestamp = jf->timestamp - jb->window_timestamp;
if (offset_timestamp >= 0)
break;
}
return (jf) ? offset_timestamp : -1;
}
/* get next data chunk from jitterbuffer */
jitter_frame_t *jitter_load(jitter_t *jb)
{
jitter_frame_t *jf;
int32_t offset_timestamp;
#ifdef HEAVY_DEBUG
LOGP(DJITTER, LOGL_DEBUG, "%sLoad chunk of %d samples.\n", jb->name, length);
static struct timespec tv;
clock_gettime(CLOCK_REALTIME, &tv);
LOGP(DJITTER, LOGL_DEBUG, "%s Load frame. %ld.%04ld\n", jb->name, tv.tv_sec, tv.tv_nsec / 1000000);
#endif
/* now unlock jitter buffer */
jb->unlocked = 1;
jb->unlocked = true;
/* reduce delay */
jb->delay_counter += jb->sample_duration * (double)length;
if (jb->delay_counter >= jb->delay_interval) {
if (jb->min_delay_value >= 0)
LOGP(DJITTER, LOGL_DEBUG, "%s Statistics: target_window_delay=%.0fms max_window_delay=%.0fms current min_delay=%.0fms\n", jb->name, (double)jb->target_window_size * jb->sample_duration * 1000.0, (double)jb->max_window_size * jb->sample_duration * 1000.0, (double)jb->min_delay_value * jb->sample_duration * 1000.0);
/* delay reduction, if maximum delay is greater than target jitter window size */
if ((jb->window_flags & JITTER_FLAG_LATENCY) && jb->min_delay_value > jb->target_window_size) {
LOGP(DJITTER, LOGL_DEBUG, "%s Reducing current minimum delay of %.0fms, because maximum delay is greater than target window size of %.0fms.\n", jb->name, (double)jb->min_delay_value * jb->sample_duration * 1000.0, (double)jb->target_window_size * jb->sample_duration * 1000.0);
/* only reduce delay to half of the target window size */
jb->window_timestamp += jb->min_delay_value - jb->target_window_size / 2;
}
jb->delay_counter -= jb->delay_interval;
jb->delay_interval = REPEAT_DELAY_INTERVAL;
jb->min_delay_value = -1;
/* get current chunk, free all chunks that are in the past */
while ((jf = jb->frame_list)) {
offset_timestamp = jf->timestamp - jb->window_timestamp;
if (offset_timestamp >= 0)
break;
/* detach and free */
jb->frame_list = jf->next;
jitter_frame_free(jf);
}
/* process all frames until output buffer is loaded */
while (length) {
/* always get frame with the lowest sequence number (1st frame) */
jf = jb->frame_list;
/* next frame in the future */
if (jf && jf->timestamp != jb->window_timestamp)
return NULL;
if (jf) {
count = jf->timestamp - jb->window_timestamp;
if (count > length)
count = length;
} else
count = length;
/* if there is no frame or we have not reached frame's time stamp, extrapolate */
if (count > 0) {
#ifdef HEAVY_DEBUG
if (jf)
LOGP(DJITTER, LOGL_DEBUG, "%s There is a frame ahead in buffer after %d samples. Interpolating gap.\n", jb->name, jf->timestamp - jb->window_timestamp);
else
LOGP(DJITTER, LOGL_DEBUG, "%s There is no frame ahead in buffer. Interpolating gap.\n", jb->name);
#endif
/* extrapolate by playing the extrapolation buffer */
while (count) {
count2 = count;
if (count2 > jb->extra_size - jb->extra_index)
count2 = jb->extra_size - jb->extra_index;
memcpy(samples, (uint8_t *)jb->extra_samples + jb->extra_index * jb->sample_size, count2 * jb->sample_size);
jb->extra_index += count2;
if (jb->extra_index == jb->extra_size) {
jb->extra_index = 0;
if ((jb->window_flags & JITTER_FLAG_REPEAT) && jb->extra_timeout_count < jb->extra_timeout_max) {
jb->extra_timeout_count++;
if (jb->extra_timeout_count == jb->extra_timeout_max) {
#ifdef HEAVY_DEBUG
LOGP(DJITTER, LOGL_DEBUG, "%s Repeated jitter buffer enough, clearing to silence.\n", jb->name);
#endif
clear_extra_buffer(jb);
}
}
}
samples = (uint8_t *)samples + count2 * jb->sample_size;
length -= count2;
jb->window_timestamp += count2;
count -= count2;
}
if (length == 0)
return;
}
/* copy samples from frame (what is not in the past) */
index = jb->window_timestamp - jf->timestamp;
while (index < jf->length) {
/* use the lowest value of 'playout length' or 'remaining packet length' */
count = length;
if (jf->length - index < count)
count = jf->length - index;
/* if extrapolation is to be written, limit count to what we can store into buffer */
if ((jb->window_flags & JITTER_FLAG_REPEAT) && jb->extra_size - jb->extra_index < count)
count = jb->extra_size - jb->extra_index;
/* copy samples from packet to play out, increment sample pointer and decrement length */
#ifdef HEAVY_DEBUG
LOGP(DJITTER, LOGL_DEBUG, "%s Copy data (offset=%u count=%u) from frame (sequence=%u timestamp=%u length=%u).\n", jb->name, index, count, jf->sequence, jf->timestamp, jf->length);
#endif
memcpy(samples, (uint8_t *)jf->samples + index * jb->sample_size, count * jb->sample_size);
samples = (uint8_t *)samples + count * jb->sample_size;
length -= count;
/* copy frame data to extrapolation buffer also, increment index */
if ((jb->window_flags & JITTER_FLAG_REPEAT)) {
memcpy((uint8_t *)jb->extra_samples + jb->extra_index * jb->sample_size, (uint8_t *)jf->samples + index * jb->sample_size, count * jb->sample_size);
jb->extra_index += count;
if (jb->extra_index == jb->extra_size)
jb->extra_index = 0;
jb->extra_timeout_count = 0; /* now we have new data, we reset timeout condition */
}
/* increment time stamp */
jb->window_timestamp += count;
index += count;
/* if there was enough to play out, we are done */
if (length == 0)
return;
}
/* free frame, because all samples are now in the past */
/* detach, and return */
if (jf)
jb->frame_list = jf->next;
free(jf);
return jf;
}
/* now go for next loop, in case there is still date to play out */
/* advance time stamp of jitter buffer */
void jitter_advance(jitter_t *jb, uint32_t offset)
{
if (!jb->window_valid)
return;
jb->window_timestamp += offset;
/* increment timer to check delay */
jb->delay_counter += jb->sample_duration * (double)offset;
}
/* load samples from jitter buffer
* store in spl_buf until all copied
* conceal, if frame is missing
* ceate silence, if no spl_buf exists in the first place */
void jitter_load_samples(jitter_t *jb, uint8_t *spl, int len, size_t sample_size, void (*conceal)(uint8_t *spl, int len, void *priv), void *conceal_priv)
{
jitter_frame_t *jf;
int32_t offset;
void (*decoder)(uint8_t *src_data, int src_len, uint8_t **dst_data, int *dst_len, void *priv);
void *decoder_priv;
uint8_t *payload;
int payload_len;
int tocopy;
#ifdef VISUAL_DEBUG
int32_t offset_timestamp;
char debug[jb->max_window_size + 32];
int last = 0;
memset(debug, ' ', sizeof(debug));
for (jf = jb->frame_list; jf; jf = jf->next) {
offset_timestamp = jf->timestamp - jb->window_timestamp;
if (offset_timestamp < 0)
continue;
offset_timestamp = (int)((double)offset_timestamp * jb->sample_duration * 1000.0);
debug[offset_timestamp] = '0' + jf->sequence % 10;
last = offset_timestamp + 1;
}
debug[last] = '\0';
LOGP(DJITTER, LOGL_DEBUG, "%s:%s\n", jb->name, debug);
#endif
next_chunk:
/* nothing more to return */
if (!len)
return;
copy_chunk:
/* consume from buffer, if valid */
if (jb->spl_buf && jb->spl_valid) {
tocopy = jb->spl_len - jb->spl_pos;
if (tocopy > len)
tocopy = len;
#ifdef HEAVY_DEBUG
LOGP(DJITTER, LOGL_DEBUG, "%s loading %d samples: from valid sample buffer.\n", jb->name, tocopy);
#endif
/* advance jitter buffer */
jitter_advance(jb, tocopy);
memcpy(spl, jb->spl_buf + jb->spl_pos * sample_size, tocopy * sample_size);
spl += tocopy * sample_size;
len -= tocopy;
jb->spl_pos += tocopy;
if (jb->spl_pos == jb->spl_len) {
jb->spl_pos = 0;
jb->spl_valid = false;
}
goto next_chunk;
}
/* get offset to next frame in jitter buffer */
offset = jitter_offset(jb);
/* jitter buffer is empty, so we must conceal all samples we have */
if (offset < 0)
offset = len;
/* if we have an offset, we need to conceal the samples */
if (offset > 0) {
/* only process as much samples as need */
if (offset > len)
offset = len;
#ifdef HEAVY_DEBUG
LOGP(DJITTER, LOGL_DEBUG, "%s concealing %d samples: from invalid sample buffer.\n", jb->name, offset);
#endif
/* advance jitter buffer */
jitter_advance(jb, offset);
/* if there is no buffer, allocate 20ms, filled with 0 */
if (!jb->spl_buf) {
jb->spl_len = jb->samples_20ms;
jb->spl_buf = calloc(jb->spl_len, sample_size);
}
/* do until all samples are processed */
while (offset) {
tocopy = jb->spl_len - jb->spl_pos;
if (tocopy > offset)
tocopy = offset;
if (conceal)
conceal(jb->spl_buf + jb->spl_pos * sample_size, tocopy, conceal_priv);
memcpy(spl, jb->spl_buf + jb->spl_pos * sample_size, tocopy * sample_size);
spl += tocopy * sample_size;
len -= tocopy;
jb->spl_pos += tocopy;
if (jb->spl_pos == jb->spl_len)
jb->spl_pos = 0;
offset -= tocopy;
}
goto next_chunk;
}
/* load from jitter buffer (it should work, because offset equals 0 */
jf = jitter_load(jb);
if (!jf) {
LOGP(DJITTER, LOGL_ERROR, "%s Failed to get frame from jitter buffer, please fix!\n", jb->name);
jitter_reset(jb);
return;
}
#ifdef HEAVY_DEBUG
LOGP(DJITTER, LOGL_DEBUG, "%s loading new frame to sample buffer.\n", jb->name);
#endif
/* get data from frame */
jitter_frame_get(jf, &decoder, &decoder_priv, &payload, &payload_len, NULL, NULL, NULL, NULL);
/* free previous buffer */
free(jb->spl_buf);
jb->spl_buf = NULL;
jb->spl_pos = 0;
/* decode */
if (decoder) {
decoder(payload, payload_len, &jb->spl_buf, &jb->spl_len, decoder_priv);
} else {
jb->spl_buf = malloc(payload_len);
if (!jb->spl_buf)
return;
jb->spl_len = payload_len / sample_size;
memcpy(jb->spl_buf, payload, payload_len);
}
jb->spl_len = jb->spl_len / sample_size;
jb->spl_valid = true;
/* free jiter frame */
jitter_frame_free(jf);
goto copy_chunk;
}
void jitter_conceal_s16(uint8_t *_spl, int len, void __attribute__((unused)) *priv)
{
int16_t *spl = (int16_t *)_spl;
while (len) {
*spl++ /= 1.5;
len--;
}
}

67
src/libjitter/jitter.h
View File

@ -4,57 +4,64 @@
#define JITTER_FLAG_REPEAT (1 << 1) // repeat audio to extrapolate gaps
/* window settings for low latency audio and extrapolation of gaps */
#define JITTER_AUDIO 0.050, 1.000, JITTER_FLAG_LATENCY | JITTER_FLAG_REPEAT
#define JITTER_AUDIO 0.060, 1.000, JITTER_FLAG_LATENCY | JITTER_FLAG_REPEAT
/* window settings for analog data (fax/modem) or digial data (HDLC) */
#define JITTER_DATA 0.100, 0.200, JITTER_FLAG_NONE
typedef struct jitter_frame {
struct jitter_frame *next;
void (*decoder)(uint8_t *src_data, int src_len, uint8_t **dst_data, int *dst_len, void *priv);
void *decoder_priv;
uint8_t marker;
uint16_t sequence;
uint32_t timestamp;
int length;
uint8_t samples[0];
uint32_t ssrc;
int size;
uint8_t data[0];
} jitter_frame_t;
typedef struct jitter {
char name[64];
/* sample properties */
int sample_size;
double sample_duration;
/* automatic sequence generation */
uint16_t next_sequence;
uint32_t next_timestamp;
/* frame properties */
double sample_duration; /* duration of a frame (ms) */
int samples_20ms; /* samples to compensate a gap of unknown size */
/* window properties */
int unlocked;
uint32_t window_flags;
int target_window_size;
int max_window_size;
int window_valid;
uint32_t window_ssrc;
uint32_t window_timestamp;
bool unlocked; /* jitter buffer will be locked until some reads from it */
uint32_t window_flags; /* flags to alter behaviour of jitter buffer */
int target_window_size; /* target size of window (frames) */
int max_window_size; /* maximum size of window (frames) */
bool window_valid; /* set, if first frame has been received */
uint32_t window_ssrc; /* current sync source of window */
uint32_t window_timestamp; /* lowest timestamp number in window */
/* reduction of delay */
double delay_interval;
double delay_counter;
int32_t min_delay_value;
/* extrapolation */
int extra_size;
int extra_index;
void *extra_samples;
int extra_timeout_max;
int extra_timeout_count;
double delay_interval; /* interval for delay measurement (seconds) */
double delay_counter; /* current counter to count interval (seconds) */
int min_delay; /* minimum delay measured during interval (frames) */
/* list of frames */
jitter_frame_t *frame_list;
/* sample buffer (optional) */
uint8_t *spl_buf; /* current samples buffer */
int spl_pos; /* position of in buffer */
int spl_len; /* total buffer size */
bool spl_valid; /* if buffer has valid frame (not repeated) */
} jitter_t;
int jitter_create(jitter_t *jb, const char *name, double samplerate, int sample_size, double target_window_duration, double max_window_duration, uint32_t window_flags);
int jitter_create(jitter_t *jb, const char *name, double samplerate, double target_window_duration, double max_window_duration, uint32_t window_flags);
void jitter_reset(jitter_t *jb);
void jitter_destroy(jitter_t *jb);
void jitter_save(jitter_t *jb, void *samples, int length, int has_sequence, uint16_t sequence, uint32_t timestamp, uint32_t ssrc);
void jitter_load(jitter_t *jb, void *samples, int length);
jitter_frame_t *jitter_frame_alloc(void (*decoder)(uint8_t *src_data, int src_len, uint8_t **dst_data, int *dst_len, void *priv), void *decoder_priv, uint8_t *data, int size, uint8_t marker, uint16_t sequence, uint32_t timestamp, uint32_t ssrc);
void jitter_frame_free(jitter_frame_t *jf);
void jitter_frame_get(jitter_frame_t *jf, void (**decoder)(uint8_t *src_data, int src_len, uint8_t **dst_data, int *dst_len, void *priv), void **decoder_priv, uint8_t **data, int *size, uint8_t *marker, uint16_t *sequence, uint32_t *timestamp, uint32_t *ssrc);
void jitter_save(jitter_t *jb, jitter_frame_t *jf);
int32_t jitter_offset(jitter_t *jb);
jitter_frame_t *jitter_load(jitter_t *jb);
void jitter_advance(jitter_t *jb, uint32_t offset);
void jitter_load_samples(jitter_t *jb, uint8_t *spl, int len, size_t sample_size, void (*conceal)(uint8_t *spl, int len, void *priv), void *conceal_priv);
void jitter_conceal_s16(uint8_t *_spl, int len, void __attribute__((unused)) *priv);

5
src/pstn/main.c
View File

@ -150,7 +150,7 @@ static void print_help()
printf(" digit '0', two pulses are digit '1', and so on.\n");
printf(" --new-zealand\n");
printf(" Translate pulses from New Zealand rotary phone into digits. Ten pulses\n");
printf(" area '0', nine pulses digit '9', and so on.\n");
printf(" are digit '0', nine pulses are digit '1', and so on.\n");
printf(" -r --realtime <prio>\n");
printf(" Set prio: 0 to disable, 99 for maximum (default = %d)\n", rt_prio);
printf(" -C --cc \"<osmo-cc arg>\" [--cc ...]\n");
@ -435,6 +435,9 @@ int main(int argc, char *argv[])
if (law == 'u')
isdn_tone_generate_ulaw_samples();
/* generate conealment table */
init_law(law);
/* check subscribers and their ringing types */
if (subscriber_num == 0)
subscriber_num = 1;

54
src/pstn/pstn.c
View File

@ -166,6 +166,33 @@ static const char *timer_ident_name(enum timer_ident ident)
}
};
static uint8_t law_conceal[256];
void init_law(char law)
{
uint8_t all_law[256], *conceal_data;
int16_t *spl;
int dummy_len;
int i;
for (i = 0; i < 256; i++)
all_law[i] = i;
/* concealment */
if (law == 'a')
g711_decode_alaw_flipped(all_law, 256, (uint8_t **)&spl, &dummy_len, NULL);
else
g711_decode_ulaw_flipped(all_law, 256, (uint8_t **)&spl, &dummy_len, NULL);
jitter_conceal_s16((uint8_t *)spl, 256, NULL);
if (law == 'a')
g711_encode_alaw_flipped((uint8_t *)spl, 512, &conceal_data, &dummy_len, NULL);
else
g711_encode_ulaw_flipped((uint8_t *)spl, 512, &conceal_data, &dummy_len, NULL);
memcpy(law_conceal, conceal_data, 256);
free(conceal_data);
free(spl);
}
/*
* dial hints
*/
@ -546,9 +573,9 @@ int pstn_init(pstn_t *pstn, const char *name, const char *socketname, const char
/* allocate jitter buffer */
if (pstn->tx_delay)
rc = jitter_create(&pstn->tx_dejitter, "tx", 8000, sizeof(uint8_t), (double)pstn->tx_delay / 1000.0, (double)pstn->tx_delay / 1000.0 * 2.0, JITTER_FLAG_NONE);
rc = jitter_create(&pstn->tx_dejitter, "tx", 8000, (double)pstn->tx_delay / 1000.0, (double)pstn->tx_delay / 1000.0 * 2.0, JITTER_FLAG_NONE);
else
rc = jitter_create(&pstn->tx_dejitter, "tx", 8000, sizeof(uint8_t), JITTER_AUDIO);
rc = jitter_create(&pstn->tx_dejitter, "tx", 8000, JITTER_AUDIO);
if (rc < 0)
return rc;
@ -572,16 +599,20 @@ int pstn_init(pstn_t *pstn, const char *name, const char *socketname, const char
*/
/* take audio from CC (this is alaw or ulaw as specified) and store in jitter buffer */
void rtp_receive(struct osmo_cc_session_codec *codec, uint8_t __attribute__((unused)) marker, uint16_t sequence, uint32_t timestamp, uint32_t ssrc, uint8_t *data, int len)
void rtp_receive(struct osmo_cc_session_codec *codec, uint8_t marker, uint16_t sequence, uint32_t timestamp, uint32_t ssrc, uint8_t *payload, int payload_len)
{
struct call *pstn_call = codec->media->session->priv;
pstn_t *pstn = pstn_call->pstn;
jitter_frame_t *jf;
/* not the active call, drop audio */
if (pstn_call != pstn->call[PSTN_CALL_ACTIVE])
return;
jitter_save(&pstn->tx_dejitter, data, len, 1, sequence, timestamp, ssrc);
jf = jitter_frame_alloc(codec->decoder, pstn_call, payload, payload_len, marker, sequence, timestamp, ssrc);
if (!jf)
return;
jitter_save(&pstn->tx_dejitter, jf);
}
static void dtmf_on(pstn_t *pstn)
@ -767,10 +798,19 @@ static void send_noise(struct call *pstn_call, int len)
g711_encode_alaw_flipped((uint8_t *)noise, 160 * 2, &law_noise, &len_noise, NULL);
else
g711_encode_ulaw_flipped((uint8_t *)noise, 160 * 2, &law_noise, &len_noise, NULL);
osmo_cc_rtp_send(pstn_call->codec, law_noise, len_noise, 0, 1, len_noise, pstn_call);
osmo_cc_rtp_send(pstn_call->codec, law_noise, len_noise, 0, 1, len_noise);
free(law_noise);
}
static void conceal(uint8_t *spl, int len, void __attribute__((unused)) *priv)
{
int i;
/* Conceal by lowering volume using a table. */
for (i = 0; i < len; i++)
spl[i] = law_conceal[spl[i]];
}
static void bchannel_rx_tx(pstn_t *pstn, uint8_t *data, int len)
{
uint8_t *buffer = pstn->tx_buffer;
@ -808,7 +848,7 @@ static void bchannel_rx_tx(pstn_t *pstn, uint8_t *data, int len)
if (pstn->call[PSTN_CALL_ACTIVE]->state == CALL_STATE_HOLD)
send_noise(pstn->call[PSTN_CALL_ACTIVE], 160);
else
osmo_cc_rtp_send(pstn->call[PSTN_CALL_ACTIVE]->codec, buffer, 160, 0, 1, 160, pstn->call[PSTN_CALL_ACTIVE]);
osmo_cc_rtp_send(pstn->call[PSTN_CALL_ACTIVE]->codec, buffer, 160, 0, 1, 160);
}
if (pstn->call[PSTN_CALL_HOLD]->codec && pstn->call[PSTN_CALL_HOLD]->state == CALL_STATE_HOLD)
send_noise(pstn->call[PSTN_CALL_HOLD], 160);
@ -816,7 +856,7 @@ static void bchannel_rx_tx(pstn_t *pstn, uint8_t *data, int len)
}
/* load from TX jitter buffer and optionally overload with tones an with caller ID */
jitter_load(&pstn->tx_dejitter, data, len);
jitter_load_samples(&pstn->tx_dejitter, data, len, sizeof(*data), conceal, NULL);
isdn_tone_copy(&pstn->isdn_tone, data, len);
switch (pstn->callerid_state) {

1
src/pstn/pstn.h
View File

@ -190,6 +190,7 @@ typedef struct pstn {
int tx_buffer_pos; /* current position in transmit audio buffer */
} pstn_t;
void init_law(char law);
int add_dial_hint(const char *arg);
void purge_dial_hints(void);
void pstn_destroy(pstn_t *pstn_ep);