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);
}