ilbc.c

基于sip协议的网络电话源码

				     2000, 2000);
    PJ_ASSERT_RETURN(pool != NULL, PJ_ENOMEM);

    codec = pj_pool_zalloc(pool, sizeof(struct ilbc_codec));
    codec->base.op = &ilbc_op;
    codec->base.factory = factory;
    codec->pool = pool;

    pj_ansi_snprintf(codec->obj_name,  sizeof(codec->obj_name),
		     "ilbc%p", codec);

    *p_codec = &codec->base;
    return PJ_SUCCESS;
}


/*
 * Free codec.
 */
static pj_status_t ilbc_dealloc_codec( pjmedia_codec_factory *factory, 
				      pjmedia_codec *codec )
{
    struct ilbc_codec *ilbc_codec;

    PJ_ASSERT_RETURN(factory && codec, PJ_EINVAL);
    PJ_UNUSED_ARG(factory);
    PJ_ASSERT_RETURN(factory == &ilbc_factory.base, PJ_EINVAL);

    ilbc_codec = (struct ilbc_codec*) codec;
    pj_pool_release(ilbc_codec->pool);

    return PJ_SUCCESS;
}

/*
 * Init codec.
 */
static pj_status_t ilbc_codec_init(pjmedia_codec *codec, 
				   pj_pool_t *pool )
{
    PJ_UNUSED_ARG(codec);
    PJ_UNUSED_ARG(pool);
    return PJ_SUCCESS;
}

/*
 * Open codec.
 */
static pj_status_t ilbc_codec_open(pjmedia_codec *codec, 
				   pjmedia_codec_param *attr )
{
    struct ilbc_codec *ilbc_codec = (struct ilbc_codec*)codec;
    pj_status_t status;

    pj_assert(ilbc_codec != NULL);
    pj_assert(ilbc_codec->enc_ready == PJ_FALSE && 
	      ilbc_codec->dec_ready == PJ_FALSE);

    /* Decoder mode must be set */
    PJ_ASSERT_RETURN(attr->setting.dec_fmtp_mode==20 ||
		     attr->setting.dec_fmtp_mode==30, PJMEDIA_CODEC_EINMODE);

    /* The enc mode must be set in the attribute 
     * (from the mode parameter in fmtp attribute in the SDP
     * received from remote) 
     */
    if (attr->setting.enc_fmtp_mode == 0)
	attr->setting.enc_fmtp_mode = attr->setting.dec_fmtp_mode;

    PJ_ASSERT_RETURN(attr->setting.enc_fmtp_mode==20 ||
		     attr->setting.enc_fmtp_mode==30, PJMEDIA_CODEC_EINMODE);

    /* Update enc_ptime in the param */
    if (attr->setting.enc_fmtp_mode != attr->setting.dec_fmtp_mode) {
	attr->info.enc_ptime = attr->setting.enc_fmtp_mode;
    } else {
	attr->info.enc_ptime = 0;
    }

    /* Create enc */
    ilbc_codec->enc_frame_size = initEncode(&ilbc_codec->enc, 
					    attr->setting.enc_fmtp_mode);
    ilbc_codec->enc_samples_per_frame = CLOCK_RATE*attr->setting.enc_fmtp_mode/
					1000;
    ilbc_codec->enc_ready = PJ_TRUE;

    /* Create decoder */
    ilbc_codec->dec_samples_per_frame = initDecode(&ilbc_codec->dec,
						   attr->setting.dec_fmtp_mode,
						   attr->setting.penh);
    if (attr->setting.dec_fmtp_mode == 20)
	ilbc_codec->dec_frame_size = 38;
    else if (attr->setting.dec_fmtp_mode == 30)
	ilbc_codec->dec_frame_size = 50;
    else {
	pj_assert(!"Invalid iLBC mode");
	ilbc_codec->dec_frame_size = ilbc_codec->enc_frame_size;
    }
    ilbc_codec->dec_ready = PJ_TRUE;

    /* Save plc flags */
    ilbc_codec->plc_enabled = (attr->setting.plc != 0);

    /* Create silence detector. */
    ilbc_codec->vad_enabled = (attr->setting.vad != 0);
    status = pjmedia_silence_det_create(ilbc_codec->pool, CLOCK_RATE,
					ilbc_codec->enc_samples_per_frame,
					&ilbc_codec->vad);
    if (status != PJ_SUCCESS)
	return status;

    /* Init last_tx (not necessary because of zalloc, but better
     * be safe in case someone remove zalloc later.
     */
    pj_set_timestamp32(&ilbc_codec->last_tx, 0, 0);

    PJ_LOG(5,(ilbc_codec->obj_name, 
	      "iLBC codec opened, encoder mode=%d, decoder mode=%d",
	      attr->setting.enc_fmtp_mode, attr->setting.dec_fmtp_mode));

    return PJ_SUCCESS;
}


/*
 * Close codec.
 */
static pj_status_t ilbc_codec_close( pjmedia_codec *codec )
{
    struct ilbc_codec *ilbc_codec = (struct ilbc_codec*)codec;

    PJ_UNUSED_ARG(codec);

    PJ_LOG(5,(ilbc_codec->obj_name, "iLBC codec closed"));

    return PJ_SUCCESS;
}

/*
 * Modify codec settings.
 */
static pj_status_t  ilbc_codec_modify(pjmedia_codec *codec, 
				      const pjmedia_codec_param *attr )
{
    struct ilbc_codec *ilbc_codec = (struct ilbc_codec*)codec;

    ilbc_codec->plc_enabled = (attr->setting.plc != 0);
    ilbc_codec->vad_enabled = (attr->setting.vad != 0);

    return PJ_SUCCESS;
}

/*
 * Get frames in the packet.
 */
static pj_status_t  ilbc_codec_parse( pjmedia_codec *codec,
				     void *pkt,
				     pj_size_t pkt_size,
				     const pj_timestamp *ts,
				     unsigned *frame_cnt,
				     pjmedia_frame frames[])
{
    struct ilbc_codec *ilbc_codec = (struct ilbc_codec*)codec;
    unsigned count;

    PJ_ASSERT_RETURN(frame_cnt, PJ_EINVAL);

    count = 0;
    while (pkt_size >= ilbc_codec->dec_frame_size && count < *frame_cnt) {
	frames[count].type = PJMEDIA_FRAME_TYPE_AUDIO;
	frames[count].buf = pkt;
	frames[count].size = ilbc_codec->dec_frame_size;
	frames[count].timestamp.u64 = ts->u64 + count * 
					  ilbc_codec->dec_samples_per_frame;

	pkt = ((char*)pkt) + ilbc_codec->dec_frame_size;
	pkt_size -= ilbc_codec->dec_frame_size;

	++count;
    }

    *frame_cnt = count;
    return PJ_SUCCESS;
}

/*
 * Encode frame.
 */
static pj_status_t ilbc_codec_encode(pjmedia_codec *codec, 
				     const struct pjmedia_frame *input,
				     unsigned output_buf_len, 
				     struct pjmedia_frame *output)
{
    struct ilbc_codec *ilbc_codec = (struct ilbc_codec*)codec;
    unsigned i;

    pj_assert(ilbc_codec != NULL);
    PJ_ASSERT_RETURN(input && output, PJ_EINVAL);

    if (output_buf_len < ilbc_codec->enc_frame_size)
	return PJMEDIA_CODEC_EFRMTOOSHORT;

    if (input->size != (ilbc_codec->enc_samples_per_frame << 1))
	return PJMEDIA_CODEC_EPCMFRMINLEN;

    /* Detect silence */
    if (ilbc_codec->vad_enabled) {
	pj_bool_t is_silence;
	pj_int32_t silence_period;

	silence_period = pj_timestamp_diff32(&ilbc_codec->last_tx,
					      &input->timestamp);

	is_silence = pjmedia_silence_det_detect(ilbc_codec->vad, 
					        input->buf,
						(input->size >> 1),
						NULL);
	if (is_silence &&
	    PJMEDIA_CODEC_MAX_SILENCE_PERIOD != -1 &&
	    silence_period < PJMEDIA_CODEC_MAX_SILENCE_PERIOD)
	{
	    output->type = PJMEDIA_FRAME_TYPE_NONE;
	    output->buf = NULL;
	    output->size = 0;
	    output->timestamp = input->timestamp;
	    return PJ_SUCCESS;
	} else {
	    ilbc_codec->last_tx = input->timestamp;
	}
    }

    /* Convert to float */
    for (i=0; i<ilbc_codec->enc_samples_per_frame; ++i) {
	ilbc_codec->enc_block[i] = (float) (((pj_int16_t*)input->buf)[i]);
    }

    /* Encode */
    iLBC_encode((unsigned char *)output->buf, 
		ilbc_codec->enc_block, 
		&ilbc_codec->enc);

    output->type = PJMEDIA_FRAME_TYPE_AUDIO;
    output->size = ilbc_codec->enc.no_of_bytes;
    output->timestamp = input->timestamp;

    return PJ_SUCCESS;
}

/*
 * Decode frame.
 */
static pj_status_t ilbc_codec_decode(pjmedia_codec *codec, 
				     const struct pjmedia_frame *input,
				     unsigned output_buf_len, 
				     struct pjmedia_frame *output)
{
    struct ilbc_codec *ilbc_codec = (struct ilbc_codec*)codec;
    unsigned i;

    pj_assert(ilbc_codec != NULL);
    PJ_ASSERT_RETURN(input && output, PJ_EINVAL);

    if (output_buf_len < (ilbc_codec->dec_samples_per_frame << 1))
	return PJMEDIA_CODEC_EPCMTOOSHORT;

    if (input->size != ilbc_codec->dec_frame_size)
	return PJMEDIA_CODEC_EFRMINLEN;

    /* Decode to temporary buffer */
    iLBC_decode(ilbc_codec->dec_block, input->buf,
		&ilbc_codec->dec, 1);

    /* Convert decodec samples from float to short */
    for (i=0; i<ilbc_codec->dec_samples_per_frame; ++i) {
	((short*)output->buf)[i] = (short)ilbc_codec->dec_block[i];
    }
    output->size = (ilbc_codec->dec_samples_per_frame << 1);
    output->type = PJMEDIA_FRAME_TYPE_AUDIO;
    output->timestamp = input->timestamp;

    return PJ_SUCCESS;
}


/*
 * Recover lost frame.
 */
static pj_status_t  ilbc_codec_recover(pjmedia_codec *codec,
				      unsigned output_buf_len,
				      struct pjmedia_frame *output)
{
    struct ilbc_codec *ilbc_codec = (struct ilbc_codec*)codec;
    unsigned i;

    pj_assert(ilbc_codec != NULL);
    PJ_ASSERT_RETURN(output, PJ_EINVAL);

    if (output_buf_len < (ilbc_codec->dec_samples_per_frame << 1))
	return PJMEDIA_CODEC_EPCMTOOSHORT;

    /* Decode to temporary buffer */
    iLBC_decode(ilbc_codec->dec_block, NULL, &ilbc_codec->dec, 0);

    /* Convert decodec samples from float to short */
    for (i=0; i<ilbc_codec->dec_samples_per_frame; ++i) {
	((short*)output->buf)[i] = (short)ilbc_codec->dec_block[i];
    }
    output->size = (ilbc_codec->dec_samples_per_frame << 1);
    output->type = PJMEDIA_FRAME_TYPE_AUDIO;

    return PJ_SUCCESS;
}


#endif	/* PJMEDIA_HAS_ILBC_CODEC */