smoother.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <[email protected]>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Frame smoother manipulation routines
 *
 * \author Mark Spencer <[email protected]>
 */

/*** MODULEINFO
 <support_level>core</support_level>
 ***/

#include "asterisk.h"

#include "asterisk/_private.h"
#include "asterisk/frame.h"
#include "asterisk/astobj2.h"
#include "asterisk/time.h"
#include "asterisk/utils.h"
#include "asterisk/format.h"
#include "asterisk/codec.h"
#include "asterisk/smoother.h"

#define SMOOTHER_SIZE 8000

struct ast_smoother {
 int size;
 struct ast_format *format;
 int flags;
 float samplesperbyte;
 unsigned int opt_needs_swap:1;
 struct ast_frame f;
 struct timeval delivery;
 char data[SMOOTHER_SIZE];
 char framedata[SMOOTHER_SIZE + AST_FRIENDLY_OFFSET];
 struct ast_frame *opt;
 int len;
};

static int smoother_frame_feed(struct ast_smoother *s, struct ast_frame *f, int swap)
{
 if (s->flags & AST_SMOOTHER_FLAG_G729) {
 if (s->len % 10) {
 ast_log(LOG_NOTICE, "Dropping extra frame of G.729 since we already have a VAD frame at the end\n");
 return 0;
 }
 }
 if (swap) {
 ast_swapcopy_samples(s->data + s->len, f->data.ptr, f->samples);
 } else {
 memcpy(s->data + s->len, f->data.ptr, f->datalen);
 }
 /* If either side is empty, reset the delivery time */
 if (!s->len || ast_tvzero(f->delivery) || ast_tvzero(s->delivery)) { /* XXX really ? */
 s->delivery = f->delivery;
 }
 s->len += f->datalen;

 return 0;
}

void ast_smoother_reset(struct ast_smoother *s, int bytes)
{
 ao2_cleanup(s->format);
 memset(s, 0, sizeof(*s));
 s->size = bytes;
}

void ast_smoother_reconfigure(struct ast_smoother *s, int bytes)
{
 /* if there is no change, then nothing to do */
 if (s->size == bytes) {
 return;
 }
 /* set the new desired output size */
 s->size = bytes;
 /* if there is no 'optimized' frame in the smoother,
 * then there is nothing left to do
 */
 if (!s->opt) {
 return;
 }
 /* there is an 'optimized' frame here at the old size,
 * but it must now be put into the buffer so the data
 * can be extracted at the new size
 */
 smoother_frame_feed(s, s->opt, s->opt_needs_swap);
 s->opt = NULL;
}

struct ast_smoother *ast_smoother_new(int size)
{
 struct ast_smoother *s;
 if (size < 1)
 return NULL;
 if ((s = ast_calloc(1, sizeof(*s))))
 ast_smoother_reset(s, size);
 return s;
}

int ast_smoother_get_flags(struct ast_smoother *s)
{
 return s->flags;
}

void ast_smoother_set_flags(struct ast_smoother *s, int flags)
{
 s->flags = flags;
}

int ast_smoother_test_flag(struct ast_smoother *s, int flag)
{
 return (s->flags & flag);
}

int __ast_smoother_feed(struct ast_smoother *s, struct ast_frame *f, int swap)
{
 if (f->frametype != AST_FRAME_VOICE) {
 ast_log(LOG_WARNING, "Huh? Can't smooth a non-voice frame!\n");
 return -1;
 }
 if (!s->format) {
 s->format = ao2_bump(f->subclass.format);
 s->samplesperbyte = (float)f->samples / (float)f->datalen;
 } else if (ast_format_cmp(s->format, f->subclass.format) == AST_FORMAT_CMP_NOT_EQUAL) {
 ast_log(LOG_WARNING, "Smoother was working on %s format frames, now trying to feed %s?\n",
 ast_format_get_name(s->format), ast_format_get_name(f->subclass.format));
 return -1;
 }
 if (s->len + f->datalen > SMOOTHER_SIZE) {
 ast_log(LOG_WARNING, "Out of smoother space\n");
 return -1;
 }
 if (((f->datalen == s->size) ||
 ((f->datalen < 10) && (s->flags & AST_SMOOTHER_FLAG_G729))) &&
 !s->opt &&
 !s->len &&
 (f->offset >= AST_MIN_OFFSET)) {
 /* Optimize by sending the frame we just got
 on the next read, thus eliminating the douple
 copy */
 if (swap)
 ast_swapcopy_samples(f->data.ptr, f->data.ptr, f->samples);
 s->opt = f;
 s->opt_needs_swap = swap ? 1 : 0;
 return 0;
 }

 return smoother_frame_feed(s, f, swap);
}

struct ast_frame *ast_smoother_read(struct ast_smoother *s)
{
 struct ast_frame *opt;
 int len;

 /* IF we have an optimization frame, send it */
 if (s->opt) {
 if (s->opt->offset < AST_FRIENDLY_OFFSET)
 ast_log(LOG_WARNING, "Returning a frame of inappropriate offset (%d).\n",
 s->opt->offset);
 opt = s->opt;
 s->opt = NULL;
 return opt;
 }

 /* Make sure we have enough data */
 if (s->len < s->size) {
 /* Or, if this is a G.729 frame with VAD on it, send it immediately anyway */
 if (!((s->flags & AST_SMOOTHER_FLAG_G729) && (s->len % 10)))
 return NULL;
 }
 len = s->size;
 if (len > s->len)
 len = s->len;
 /* Make frame */
 s->f.frametype = AST_FRAME_VOICE;
 s->f.subclass.format = s->format;
 s->f.data.ptr = s->framedata + AST_FRIENDLY_OFFSET;
 s->f.offset = AST_FRIENDLY_OFFSET;
 s->f.datalen = len;
 /* Samples will be improper given VAD, but with VAD the concept really doesn't even exist */
 s->f.samples = len * s->samplesperbyte; /* XXX rounding */
 s->f.delivery = s->delivery;
 /* Fill Data */
 memcpy(s->f.data.ptr, s->data, len);
 s->len -= len;
 /* Move remaining data to the front if applicable */
 if (s->len) {
 /* In principle this should all be fine because if we are sending
 G.729 VAD, the next timestamp will take over anyawy */
 memmove(s->data, s->data + len, s->len);
 if (!ast_tvzero(s->delivery)) {
 /* If we have delivery time, increment it, otherwise, leave it at 0 */
 s->delivery = ast_tvadd(s->delivery, ast_samp2tv(s->f.samples,
 ast_format_get_sample_rate(s->format)));
 }
 }
 /* Return frame */
 return &s->f;
}

void ast_smoother_free(struct ast_smoother *s)
{
 ao2_cleanup(s->format);
 ast_free(s);
}