smoother.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * 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 <markster@digium.com>
 */
 
/*** 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 anyway */
        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);
}