scan.c

关于dvb的应用程序代码

	/* remove control characters (FIXME: handle short/long name) */
	/* FIXME: handle character set correctly (e.g. via iconv)
	 * c.f. EN 300 468 annex A */
	for (src = dest = (unsigned char *) s->service_name; *src; src++)
		if (*src >= 0x20 && (*src < 0x80 || *src > 0x9f))
			*dest++ = *src;
	*dest = '\0';
	if (!s->service_name[0]) {
		/* zap zero length names */
		free (s->service_name);
		s->service_name = 0;
	}

	info("0x%04x 0x%04x: pmt_pid 0x%04x %s -- %s (%s%s)\n",
	    s->transport_stream_id,
	    s->service_id,
	    s->pmt_pid,
	    s->provider_name, s->service_name,
	    s->running == RM_NOT_RUNNING ? "not running" :
	    s->running == RM_STARTS_SOON ? "starts soon" :
	    s->running == RM_PAUSING     ? "pausing" :
	    s->running == RM_RUNNING     ? "running" : "???",
	    s->scrambled ? ", scrambled" : "");
}

static int find_descriptor(uint8_t tag, const unsigned char *buf,
		int descriptors_loop_len,
		const unsigned char **desc, int *desc_len)
{
	while (descriptors_loop_len > 0) {
		unsigned char descriptor_tag = buf[0];
		unsigned char descriptor_len = buf[1] + 2;

		if (!descriptor_len) {
			warning("descriptor_tag == 0x%02x, len is 0\n", descriptor_tag);
			break;
		}

		if (tag == descriptor_tag) {
			if (desc)
				*desc = buf;
			if (desc_len)
				*desc_len = descriptor_len;
			return 1;
		}

		buf += descriptor_len;
		descriptors_loop_len -= descriptor_len;
	}
	return 0;
}

static void parse_descriptors(enum table_type t, const unsigned char *buf,
			      int descriptors_loop_len, void *data)
{
	while (descriptors_loop_len > 0) {
		unsigned char descriptor_tag = buf[0];
		unsigned char descriptor_len = buf[1] + 2;

		if (!descriptor_len) {
			warning("descriptor_tag == 0x%02x, len is 0\n", descriptor_tag);
			break;
		}

		switch (descriptor_tag) {
		case 0x0a:
			if (t == PMT)
				parse_iso639_language_descriptor (buf, data);
			break;

		case 0x40:
			if (t == NIT)
				parse_network_name_descriptor (buf, data);
			break;

		case 0x43:
			if (t == NIT)
				parse_satellite_delivery_system_descriptor (buf, data);
			break;

		case 0x44:
			if (t == NIT)
				parse_cable_delivery_system_descriptor (buf, data);
			break;

		case 0x48:
			if (t == SDT)
				parse_service_descriptor (buf, data);
			break;

		case 0x53:
			if (t == SDT)
				parse_ca_identifier_descriptor (buf, data);
			break;

		case 0x5a:
			if (t == NIT)
				parse_terrestrial_delivery_system_descriptor (buf, data);
			break;

		case 0x62:
			if (t == NIT)
				parse_frequency_list_descriptor (buf, data);
			break;

		case 0x83:
			/* 0x83 is in the privately defined range of descriptor tags,
			 * so we parse this only if the user says so to avoid
			 * problems when 0x83 is something entirely different... */
			if (t == NIT && vdr_dump_channum)
				parse_terrestrial_uk_channel_number (buf, data);
			break;

		default:
			verbosedebug("skip descriptor 0x%02x\n", descriptor_tag);
		};

		buf += descriptor_len;
		descriptors_loop_len -= descriptor_len;
	}
}


static void parse_pat(const unsigned char *buf, int section_length,
		      int transport_stream_id)
{
	(void)transport_stream_id;

	while (section_length > 0) {
		struct service *s;
		int service_id = (buf[0] << 8) | buf[1];

		if (service_id == 0)
			goto skip;	/* nit pid entry */

		/* SDT might have been parsed first... */
		s = find_service(current_tp, service_id);
		if (!s)
			s = alloc_service(current_tp, service_id);
		s->pmt_pid = ((buf[2] & 0x1f) << 8) | buf[3];
		if (!s->priv && s->pmt_pid) {
			s->priv = malloc(sizeof(struct section_buf));
			setup_filter(s->priv, demux_devname,
				     s->pmt_pid, 0x02, s->service_id, 1, 0, 5);

			add_filter (s->priv);
		}

skip:
		buf += 4;
		section_length -= 4;
	};
}


static void parse_pmt (const unsigned char *buf, int section_length, int service_id)
{
	int program_info_len;
	struct service *s;
        char msg_buf[14 * AUDIO_CHAN_MAX + 1];
        char *tmp;
        int i;

	s = find_service (current_tp, service_id);
	if (!s) {
		error("PMT for serivce_id 0x%04x was not in PAT\n", service_id);
		return;
	}

	s->pcr_pid = ((buf[0] & 0x1f) << 8) | buf[1];

	program_info_len = ((buf[2] & 0x0f) << 8) | buf[3];

	buf += program_info_len + 4;
	section_length -= program_info_len + 4;

	while (section_length >= 5) {
		int ES_info_len = ((buf[3] & 0x0f) << 8) | buf[4];
		int elementary_pid = ((buf[1] & 0x1f) << 8) | buf[2];

		switch (buf[0]) {
		case 0x01:
		case 0x02:
			moreverbose("  VIDEO     : PID 0x%04x\n", elementary_pid);
			if (s->video_pid == 0)
				s->video_pid = elementary_pid;
			break;
		case 0x03:
		case 0x81: /* Audio per ATSC A/53B [2] Annex B */
		case 0x04:
			moreverbose("  AUDIO     : PID 0x%04x\n", elementary_pid);
			if (s->audio_num < AUDIO_CHAN_MAX) {
				s->audio_pid[s->audio_num] = elementary_pid;
				parse_descriptors (PMT, buf + 5, ES_info_len, s);
				s->audio_num++;
			}
			else
				warning("more than %i audio channels, truncating\n",
				     AUDIO_CHAN_MAX);
			break;
		case 0x06:
			if (find_descriptor(0x56, buf + 5, ES_info_len, NULL, NULL)) {
				moreverbose("  TELETEXT  : PID 0x%04x\n", elementary_pid);
				s->teletext_pid = elementary_pid;
				break;
			}
			else if (find_descriptor(0x59, buf + 5, ES_info_len, NULL, NULL)) {
				/* Note: The subtitling descriptor can also signal
				 * teletext subtitling, but then the teletext descriptor
				 * will also be present; so we can be quite confident
				 * that we catch DVB subtitling streams only here, w/o
				 * parsing the descriptor. */
				moreverbose("  SUBTITLING: PID 0x%04x\n", elementary_pid);
				s->subtitling_pid = elementary_pid;
				break;
			}
			else if (find_descriptor(0x6a, buf + 5, ES_info_len, NULL, NULL)) {
				moreverbose("  AC3       : PID 0x%04x\n", elementary_pid);
				s->ac3_pid = elementary_pid;
				break;
			}
			/* fall through */
		default:
			moreverbose("  OTHER     : PID 0x%04x TYPE 0x%02x\n", elementary_pid, buf[0]);
		};

		buf += ES_info_len + 5;
		section_length -= ES_info_len + 5;
	};


	tmp = msg_buf;
	tmp += sprintf(tmp, "0x%04x (%.4s)", s->audio_pid[0], s->audio_lang[0]);

	if (s->audio_num > AUDIO_CHAN_MAX) {
		warning("more than %i audio channels: %i, truncating to %i\n",
		      AUDIO_CHAN_MAX, s->audio_num, AUDIO_CHAN_MAX);
		s->audio_num = AUDIO_CHAN_MAX;
	}

        for (i=1; i<s->audio_num; i++)
                tmp += sprintf(tmp, ", 0x%04x (%.4s)", s->audio_pid[i], s->audio_lang[i]);

        debug("0x%04x 0x%04x: %s -- %s, pmt_pid 0x%04x, vpid 0x%04x, apid %s\n",
	    s->transport_stream_id,
	    s->service_id,
	    s->provider_name, s->service_name,
	    s->pmt_pid, s->video_pid, msg_buf);
}


static void parse_nit (const unsigned char *buf, int section_length, int network_id)
{
	int descriptors_loop_len = ((buf[0] & 0x0f) << 8) | buf[1];

	if (section_length < descriptors_loop_len + 4)
	{
		warning("section too short: network_id == 0x%04x, section_length == %i, "
		     "descriptors_loop_len == %i\n",
		     network_id, section_length, descriptors_loop_len);
		return;
	}

	parse_descriptors (NIT, buf + 2, descriptors_loop_len, NULL);

	section_length -= descriptors_loop_len + 4;
	buf += descriptors_loop_len + 4;

	while (section_length > 6) {
		int transport_stream_id = (buf[0] << 8) | buf[1];
		struct transponder *t, tn;

		descriptors_loop_len = ((buf[4] & 0x0f) << 8) | buf[5];

		if (section_length < descriptors_loop_len + 4)
		{
			warning("section too short: transport_stream_id == 0x%04x, "
			     "section_length == %i, descriptors_loop_len == %i\n",
			     transport_stream_id, section_length,
			     descriptors_loop_len);
			break;
		}

		debug("transport_stream_id 0x%04x\n", transport_stream_id);

		memset(&tn, 0, sizeof(tn));
		tn.type = -1;
		tn.network_id = network_id;
		tn.transport_stream_id = transport_stream_id;

		parse_descriptors (NIT, buf + 6, descriptors_loop_len, &tn);

		if (tn.type == fe_info.type) {
			/* only add if develivery_descriptor matches FE type */
			t = find_transponder(tn.param.frequency);
			if (!t)
				t = alloc_transponder(tn.param.frequency);
			copy_transponder(t, &tn);
		}

		section_length -= descriptors_loop_len + 6;
		buf += descriptors_loop_len + 6;
	}
}


static void parse_sdt (const unsigned char *buf, int section_length,
		int transport_stream_id)
{
	(void)transport_stream_id;

	buf += 3;	       /*  skip original network id + reserved field */

	while (section_length >= 5) {
		int service_id = (buf[0] << 8) | buf[1];
		int descriptors_loop_len = ((buf[3] & 0x0f) << 8) | buf[4];
		struct service *s;

		if (section_length < descriptors_loop_len || !descriptors_loop_len)
		{
			warning("section too short: service_id == 0x%02x, section_length == %i, "
			     "descriptors_loop_len == %i\n",
			     service_id, section_length,
			     descriptors_loop_len);
			break;
		}

		s = find_service(current_tp, service_id);
		if (!s)
			/* maybe PAT has not yet been parsed... */
			s = alloc_service(current_tp, service_id);

		s->running = (buf[3] >> 5) & 0x7;
		s->scrambled = (buf[3] >> 4) & 1;

		parse_descriptors (SDT, buf + 5, descriptors_loop_len, s);

		section_length -= descriptors_loop_len + 5;
		buf += descriptors_loop_len + 5;
	};
}

/* ATSC PSIP VCT */
static void parse_atsc_service_loc_desc(struct service *s,const unsigned char *buf)
{
	struct ATSC_service_location_descriptor d = read_ATSC_service_location_descriptor(buf);
	int i;
	unsigned char *b = (unsigned char *) buf+5;

	s->pcr_pid = d.PCR_PID;
	for (i=0; i < d.number_elements; i++) {
		struct ATSC_service_location_element e = read_ATSC_service_location_element(b);
		switch (e.stream_type) {
			case 0x02: /* video */
				s->video_pid = e.elementary_PID;
				moreverbose("  VIDEO     : PID 0x%04x\n", e.elementary_PID);
				break;
			case 0x81: /* ATSC audio */
				if (s->audio_num < AUDIO_CHAN_MAX) {
					s->audio_pid[s->audio_num] = e.elementary_PID;
					s->audio_lang[s->audio_num][0] = (e.ISO_639_language_code >> 16) & 0xff;
					s->audio_lang[s->audio_num][1] = (e.ISO_639_language_code >> 8)  & 0xff;
					s->audio_lang[s->audio_num][2] =  e.ISO_639_language_code        & 0xff;
					s->audio_num++;
				}
				moreverbose("  AUDIO     : PID 0x%04x lang: %s\n",e.elementary_PID,s->audio_lang[s->audio_num-1]);

				break;
			default:
				warning("unhandled stream_type: %x\n",e.stream_type);
				break;
		};
		b += 6;
	}
}

static void parse_atsc_ext_chan_name_desc(struct service *s,const unsigned char *buf)
{
	unsigned char *b = (unsigned char *) buf+2;
	int i,j;
	int num_str = b[0];

	b++;
	for (i = 0; i < num_str; i++) {
		int num_seg = b[3];
		b += 4; /* skip lang code */
		for (j = 0; j < num_seg; j++) {
			int comp_type = b[0],/* mode = b[1],*/ num_bytes = b[2];

			switch (comp_type) {
				case 0x00:
					if (s->service_name)
						free(s->service_name);
					s->service_name = malloc(num_bytes * sizeof(char) + 1);
					memcpy(s->service_name,&b[3],num_bytes);
					s->service_name[num_bytes] = '\0';
					break;
				default:
					warning("compressed strings are not supported yet\n");
					break;
			}
			b += 3 + num_bytes;
		}
	}
}

static void parse_psip_descriptors(struct service *s,const unsigned char *buf,int len)
{
	unsigned char *b = (unsigned char *) buf;
	int desc_len;
	while (len > 0) {
		desc_len = b[1];
		switch (b[0]) {
			case ATSC_SERVICE_LOCATION_DESCRIPTOR_ID:
				parse_atsc_service_loc_desc(s,b);
				break;
			case ATSC_EXTENDED_CHANNEL_NAME_DESCRIPTOR_ID:
				parse_atsc_ext_chan_name_desc(s,b);
				break;
			default:
				warning("unhandled psip descriptor: %02x\n",b[0]);
				break;
		}
		b += 2 + desc_len;
		len -= 2 + desc_len;
	}
}

static void parse_psip_vct (const unsigned char *buf, int section_length,
		int table_id, int transport_stream_id)
{
	(void)section_length;
	(void)table_id;
	(void)transport_stream_id;

/*	int protocol_version = buf[0];*/
	int num_channels_in_section = buf[1];
	int i;
	int pseudo_id = 0xffff;
	unsigned char *b = (unsigned char *) buf + 2;

	for (i = 0; i < num_channels_in_section; i++) {
		struct service *s;
		struct tvct_channel ch = read_tvct_channel(b);

		switch (ch.service_type) {
			case 0x01:
				info("analog channels won't be put info channels.conf\n");
				break;
			case 0x02: /* ATSC TV */
			case 0x03: /* ATSC Radio */
				break;
			case 0x04: /* ATSC Data */
			default:
				continue;
		}

		if (ch.program_number == 0)
			ch.program_number = --pseudo_id;

		s = find_service(current_tp, ch.program_number);
		if (!s)
			s = alloc_service(current_tp, ch.program_number);

		if (s->service_name)
			free(s->service_name);

		s->service_name = malloc(7*sizeof(unsigned char));
		/* TODO find a better solution to convert UTF-16 */
		s->service_name[0] = ch.short_name0;
		s->service_name[1] = ch.short_name1;
		s->service_name[2] = ch.short_name2;
		s->service_name[3] = ch.short_name3;
		s->service_name[4] = ch.short_name4;
		s->service_name[5] = ch.short_name5;
		s->service_name[6] = ch.short_name6;

		parse_psip_descriptors(s,&b[32],ch.descriptors_length);

		s->channel_num = ch.major_channel_number << 10 | ch.minor_channel_number;

		if (ch.hidden) {
			s->running = RM_NOT_RUNNING;
			info("service is not running, pseudo program_number.");
		} else {
			s->running = RM_RUNNING;
			info("service is running.");
		}

		info(" Channel number: %d:%d. Name: '%s'\n",
			ch.major_channel_number, ch.minor_channel_number,s->service_name);

		b += 32 + ch.descriptors_length;
	}
}

static int get_bit (uint8_t *bitfield, int bit)
{
	return (bitfield[bit/8] >> (bit % 8)) & 1;
}

static void set_bit (uint8_t *bitfield, int bit)
{
	bitfield[bit/8] |= 1 << (bit % 8);
}


/**
 *   returns 0 when more sections are expected
 *	   1 when all sections are read on this pid
 *	   -1 on invalid table id
 */
static int parse_section (struct section_buf *s)
{
	const unsigned char *buf = s->buf;
	int table_id;
	int section_length;
	int table_id_ext;
	int section_version_number;
	int section_number;
	int last_section_number;
	int i;

	table_id = buf[0];

	if (s->table_id != table_id)
		return -1;

	section_length = ((buf[1] & 0x0f) << 8) | buf[2];

	table_id_ext = (buf[3] << 8) | buf[4];
	section_version_number = (buf[5] >> 1) & 0x1f;
	section_number = buf[6];
	last_section_number = buf[7];

	if (s->segmented && s->table_id_ext != -1 && s->table_id_ext != table_id_ext) {
		/* find or allocate actual section_buf matching table_id_ext */
		while (s->next_seg) {
			s = s->next_seg;
			if (s->table_id_ext == table_id_ext)
				break;
		}
		if (s->table_id_ext != table_id_ext) {
			assert(s->next_seg == NULL);
			s->next_seg = calloc(1, sizeof(struct section_buf));
			s->next_seg->segmented = s->segmented;
			s->next_seg->run_once = s->run_once;
			s->next_seg->timeout = s->timeout;
			s = s->next_seg;
			s->table_id = table_id;
			s->table_id_ext = table_id_ext;
			s->section_version_number = section_version_number;
		}
	}

	if (s->section_version_number != section_version_number ||
			s->table_id_ext != table_id_ext) {
		struct section_buf *next_seg = s->next_seg;

		if (s->section_version_number != -1 && s->table_id_ext != -1)
			debug("section version_number or table_id_ext changed "
				"%d -> %d / %04x -> %04x\n",
				s->section_version_number, section_version_number,
				s->table_id_ext, table_id_ext);
		s->table_id_ext = table_id_ext;
		s->section_version_number = section_version_number;
		s->sectionfilter_done = 0;
		memset (s->section_done, 0, sizeof(s->section_done));
		s->next_seg = next_seg;
	}

	buf += 8;			/* past generic table header */
	section_length -= 5 + 4;	/* header + crc */
	if (section_length < 0) {