abstract_jb.c

			frame = &ast_null_frame;
			break;
		case AST_JB_IMPL_INTERP:
			if (framedata->last_format) {
				struct ast_frame tmp = { 0, };

				tmp.frametype = AST_FRAME_VOICE;
				tmp.subclass.format = framedata->last_format;
				/* example: 8000hz / (1000 / 20ms) = 160 samples */
				tmp.samples = ast_format_get_sample_rate(framedata->last_format) / (1000 / framedata->timer_interval);
				tmp.delivery = ast_tvadd(framedata->start_tv, ast_samp2tv(next, 1000));
				tmp.offset = AST_FRIENDLY_OFFSET;
				tmp.src  = "func_jitterbuffer interpolation";
				ast_frfree(frame);
				frame = ast_frdup(&tmp);
				break;
			}
			/* else fall through */
		case AST_JB_IMPL_NOFRAME:
			ast_frfree(frame);
			frame = &ast_null_frame;
			break;
		}
	}

	if (frame->frametype == AST_FRAME_CONTROL) {
		switch(frame->subclass.integer) {
		case AST_CONTROL_HOLD:
		case AST_CONTROL_UNHOLD:
		case AST_CONTROL_T38_PARAMETERS:
		case AST_CONTROL_SRCUPDATE:
		case AST_CONTROL_SRCCHANGE:
			framedata->jb_impl->force_resync(framedata->jb_obj);
			break;
		default:
			break;
		}
	}

	return frame;
}

/* set defaults */
static int jb_framedata_init(struct jb_framedata *framedata, struct ast_jb_conf *jb_conf)
{
	int jb_impl_type = DEFAULT_TYPE;
	/* Initialize defaults */
	framedata->timer_fd = -1;
	memcpy(&framedata->jb_conf, jb_conf, sizeof(*jb_conf));

	/* Figure out implementation type from the configuration implementation string */
	if (!ast_strlen_zero(jb_conf->impl)) {
		if (!strcasecmp(jb_conf->impl, "fixed")) {
			jb_impl_type = AST_JB_FIXED;
		} else if (!strcasecmp(jb_conf->impl, "adaptive")) {
			jb_impl_type = AST_JB_ADAPTIVE;
		} else {
			ast_log(LOG_WARNING, "Unknown Jitterbuffer type %s. Failed to create jitterbuffer.\n", jb_conf->impl);
			return -1;
		}
	}

	if (!(framedata->jb_impl = ast_jb_get_impl(jb_impl_type))) {
		return -1;
	}

	if (!(framedata->timer = ast_timer_open())) {
		return -1;
	}

	framedata->timer_fd = ast_timer_fd(framedata->timer);
	framedata->timer_interval = DEFAULT_TIMER_INTERVAL;
	ast_timer_set_rate(framedata->timer, 1000 / framedata->timer_interval);
	framedata->start_tv = ast_tvnow();

	framedata->jb_obj = framedata->jb_impl->create(&framedata->jb_conf);
	return 0;
}


void ast_jb_create_framehook(struct ast_channel *chan, struct ast_jb_conf *jb_conf, int prefer_existing)
{
	struct jb_framedata *framedata;
	struct ast_datastore *datastore = NULL;
	struct ast_framehook_interface interface = {
		.version = AST_FRAMEHOOK_INTERFACE_VERSION,
		.event_cb = hook_event_cb,
		.destroy_cb = hook_destroy_cb,
	};
	int i = 0;

	/* If disabled, strip any existing jitterbuffer and don't replace it. */
	if (!strcasecmp(jb_conf->impl, "disabled")) {
		int *id;
		ast_channel_lock(chan);
		if ((datastore = ast_channel_datastore_find(chan, &jb_datastore, NULL))) {
			id = datastore->data;
			ast_framehook_detach(chan, *id);
			ast_channel_datastore_remove(chan, datastore);
			ast_datastore_free(datastore);
		}
		ast_channel_unlock(chan);
		return;
	}

	if (!(framedata = ast_calloc(1, sizeof(*framedata)))) {
		return;
	}

	if (jb_framedata_init(framedata, jb_conf)) {
		jb_framedata_destroy(framedata);
		return;
	}

	interface.data = framedata;

	ast_channel_lock(chan);
	i = ast_framehook_attach(chan, &interface);
	if (i >= 0) {
		int *id;
		if ((datastore = ast_channel_datastore_find(chan, &jb_datastore, NULL))) {
			/* There is already a jitterbuffer on the channel. */
			if (prefer_existing) {
				/* We prefer the existing jitterbuffer, so remove the new one and keep the old one. */
				ast_framehook_detach(chan, i);
				ast_channel_unlock(chan);
				return;
			}
			/* We prefer the new jitterbuffer, so strip the old one. */
			id = datastore->data;
			ast_framehook_detach(chan, *id);
			ast_channel_datastore_remove(chan, datastore);
			ast_datastore_free(datastore);
		}

		if (!(datastore = ast_datastore_alloc(&jb_datastore, NULL))) {
			ast_framehook_detach(chan, i);
			ast_channel_unlock(chan);
			return;
		}

		if (!(id = ast_calloc(1, sizeof(int)))) {
			ast_datastore_free(datastore);
			ast_framehook_detach(chan, i);
			ast_channel_unlock(chan);
			return;
		}

		*id = i; /* Store off the id. The channel is still locked so it is safe to access this ptr. */
		datastore->data = id;
		ast_channel_datastore_add(chan, datastore);

		ast_channel_set_fd(chan, AST_JITTERBUFFER_FD, framedata->timer_fd);
	} else {
		jb_framedata_destroy(framedata);
		framedata = NULL;
	}
	ast_channel_unlock(chan);
}