l16.c

基于sip协议的网络电话源码

    if (count < *max_count) {
	/* 11025 Hz mono */
	codecs[count].type = PJMEDIA_TYPE_AUDIO;
	codecs[count].pt = PJMEDIA_RTP_PT_L16_11KHZ_MONO;
	codecs[count].encoding_name = STR_L16;
	codecs[count].clock_rate = 11025;
	codecs[count].channel_cnt = 1;
	++count;
    }

    if (count < *max_count) {
	/* 11025 Hz stereo */
	codecs[count].type = PJMEDIA_TYPE_AUDIO;
	codecs[count].pt = PJMEDIA_RTP_PT_L16_11KHZ_STEREO;
	codecs[count].encoding_name = STR_L16;
	codecs[count].clock_rate = 11025;
	codecs[count].channel_cnt = 2;
	++count;
    }

    if (count < *max_count) {
	/* 16000 Hz mono */
	codecs[count].type = PJMEDIA_TYPE_AUDIO;
	codecs[count].pt = PJMEDIA_RTP_PT_L16_16KHZ_MONO;
	codecs[count].encoding_name = STR_L16;
	codecs[count].clock_rate = 16000;
	codecs[count].channel_cnt = 1;
	++count;
    }


    if (count < *max_count) {
	/* 16000 Hz stereo */
	codecs[count].type = PJMEDIA_TYPE_AUDIO;
	codecs[count].pt = PJMEDIA_RTP_PT_L16_16KHZ_STEREO;
	codecs[count].encoding_name = STR_L16;
	codecs[count].clock_rate = 16000;
	codecs[count].channel_cnt = 2;
	++count;
    }

    if (count < *max_count) {
	/* 22050 Hz mono */
	codecs[count].type = PJMEDIA_TYPE_AUDIO;
	codecs[count].pt = PJMEDIA_RTP_PT_L16_22KHZ_MONO;
	codecs[count].encoding_name = STR_L16;
	codecs[count].clock_rate = 22050;
	codecs[count].channel_cnt = 1;
	++count;
    }


    if (count < *max_count) {
	/* 22050 Hz stereo */
	codecs[count].type = PJMEDIA_TYPE_AUDIO;
	codecs[count].pt = PJMEDIA_RTP_PT_L16_22KHZ_STEREO;
	codecs[count].encoding_name = STR_L16;
	codecs[count].clock_rate = 22050;
	codecs[count].channel_cnt = 2;
	++count;
    }

    if (count < *max_count) {
	/* 32000 Hz mono */
	codecs[count].type = PJMEDIA_TYPE_AUDIO;
	codecs[count].pt = PJMEDIA_RTP_PT_L16_32KHZ_MONO;
	codecs[count].encoding_name = STR_L16;
	codecs[count].clock_rate = 32000;
	codecs[count].channel_cnt = 1;
	++count;
    }

    if (count < *max_count) {
	/* 32000 Hz stereo */
	codecs[count].type = PJMEDIA_TYPE_AUDIO;
	codecs[count].pt = PJMEDIA_RTP_PT_L16_32KHZ_STEREO;
	codecs[count].encoding_name = STR_L16;
	codecs[count].clock_rate = 32000;
	codecs[count].channel_cnt = 2;
	++count;
    }

    if (count < *max_count) {
	/* 48KHz mono */
	codecs[count].type = PJMEDIA_TYPE_AUDIO;
	codecs[count].pt = PJMEDIA_RTP_PT_L16_48KHZ_MONO;
	codecs[count].encoding_name = STR_L16;
	codecs[count].clock_rate = 48000;
	codecs[count].channel_cnt = 1;
	++count;
    }

    if (count < *max_count) {
	/* 48KHz stereo */
	codecs[count].type = PJMEDIA_TYPE_AUDIO;
	codecs[count].pt = PJMEDIA_RTP_PT_L16_48KHZ_MONO;
	codecs[count].encoding_name = STR_L16;
	codecs[count].clock_rate = 48000;
	codecs[count].channel_cnt = 2;
	++count;
    }


    *max_count = count;

    return PJ_SUCCESS;
}

static pj_status_t l16_alloc_codec( pjmedia_codec_factory *factory, 
				    const pjmedia_codec_info *id,
				    pjmedia_codec **p_codec)
{
    pjmedia_codec *codec = NULL;
    struct l16_data *data;
    unsigned ptime;

    PJ_ASSERT_RETURN(factory==&l16_factory.base, PJ_EINVAL);

    /* Lock mutex. */
    pj_mutex_lock(l16_factory.mutex);

    /* Allocate new codec if no more is available */
    if (pj_list_empty(&l16_factory.codec_list)) {

	codec = pj_pool_alloc(l16_factory.pool, sizeof(pjmedia_codec));
	codec->codec_data = pj_pool_alloc(l16_factory.pool, 
					  sizeof(struct l16_data));
	codec->factory = factory;
	codec->op = &l16_op;

    } else {
	codec = l16_factory.codec_list.next;
	pj_list_erase(codec);
    }

    /* Init private data */
    ptime = GET_PTIME(id->clock_rate);
    data = codec->codec_data;
    data->frame_size = ptime * id->clock_rate * id->channel_cnt * 2 / 1000;

    /* Zero the list, for error detection in l16_dealloc_codec */
    codec->next = codec->prev = NULL;

    *p_codec = codec;

    /* Unlock mutex. */
    pj_mutex_unlock(l16_factory.mutex);

    return PJ_SUCCESS;
}

static pj_status_t l16_dealloc_codec(pjmedia_codec_factory *factory, 
				     pjmedia_codec *codec )
{
    
    PJ_ASSERT_RETURN(factory==&l16_factory.base, PJ_EINVAL);

    /* Check that this node has not been deallocated before */
    pj_assert (codec->next==NULL && codec->prev==NULL);
    if (codec->next!=NULL || codec->prev!=NULL) {
	return PJ_EINVALIDOP;
    }

    /* Lock mutex. */
    pj_mutex_lock(l16_factory.mutex);

    /* Insert at the back of the list */
    pj_list_insert_before(&l16_factory.codec_list, codec);

    /* Unlock mutex. */
    pj_mutex_unlock(l16_factory.mutex);

    return PJ_SUCCESS;
}

static pj_status_t l16_init( pjmedia_codec *codec, pj_pool_t *pool )
{
    /* There's nothing to do here really */
    PJ_UNUSED_ARG(codec);
    PJ_UNUSED_ARG(pool);

    return PJ_SUCCESS;
}

static pj_status_t l16_open(pjmedia_codec *codec, 
			    pjmedia_codec_param *attr )
{
    /* Nothing to do.. */
    PJ_UNUSED_ARG(codec);
    PJ_UNUSED_ARG(attr);
    return PJ_SUCCESS;
}

static pj_status_t l16_close( pjmedia_codec *codec )
{
    PJ_UNUSED_ARG(codec);
    /* Nothing to do */
    return PJ_SUCCESS;
}

static pj_status_t  l16_modify(pjmedia_codec *codec, 
			       const pjmedia_codec_param *attr )
{
    /* Don't want to do anything. */
    PJ_UNUSED_ARG(codec);
    PJ_UNUSED_ARG(attr);
    return PJ_EINVALIDOP;
}

static pj_status_t  l16_parse( pjmedia_codec *codec,
			       void *pkt,
			       pj_size_t pkt_size,
			       const pj_timestamp *ts,
			       unsigned *frame_cnt,
			       pjmedia_frame frames[])
{
    unsigned count = 0;
    struct l16_data *data = (struct l16_data*) codec->codec_data;

    PJ_UNUSED_ARG(codec);
    PJ_ASSERT_RETURN(frame_cnt, PJ_EINVAL);

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

	pkt = ((char*)pkt) + data->frame_size;
	pkt_size -= data->frame_size;

	++count;
    }

    *frame_cnt = count;
    return PJ_SUCCESS;
}

static pj_status_t l16_encode(pjmedia_codec *codec, 
			      const struct pjmedia_frame *input,
			      unsigned output_buf_len, 
			      struct pjmedia_frame *output)
{
    const pj_int16_t *samp = (const pj_int16_t*) input->buf;
    const pj_int16_t *samp_end = samp + input->size/sizeof(pj_int16_t);
    pj_int16_t *samp_out = (pj_int16_t*) output->buf;    


    PJ_UNUSED_ARG(codec);


    /* Check output buffer length */
    if (output_buf_len < input->size)
	return PJMEDIA_CODEC_EFRMTOOSHORT;


    /* Encode */
#if defined(PJ_IS_LITTLE_ENDIAN) && PJ_IS_LITTLE_ENDIAN!=0
    while (samp!=samp_end)
	*samp_out++ = pj_htons(*samp++);
#endif


    /* Done */
    output->type = PJMEDIA_FRAME_TYPE_AUDIO;
    output->size = input->size;

    return PJ_SUCCESS;
}

static pj_status_t l16_decode(pjmedia_codec *codec, 
			      const struct pjmedia_frame *input,
			      unsigned output_buf_len, 
			      struct pjmedia_frame *output)
{
    const pj_int16_t *samp = (const pj_int16_t*) input->buf;
    const pj_int16_t *samp_end = samp + input->size/sizeof(pj_int16_t);
    pj_int16_t *samp_out = (pj_int16_t*) output->buf;    


    PJ_UNUSED_ARG(codec);


    /* Check output buffer length */
    if (output_buf_len < input->size)
	return PJMEDIA_CODEC_EPCMTOOSHORT;


    /* Decode */
#if defined(PJ_IS_LITTLE_ENDIAN) && PJ_IS_LITTLE_ENDIAN!=0
    while (samp!=samp_end)
	*samp_out++ = pj_htons(*samp++);
#endif


    output->type = PJMEDIA_FRAME_TYPE_AUDIO;
    output->size = input->size;

    return PJ_SUCCESS;
}


#endif	/* PJMEDIA_HAS_L16_CODEC */