/* * findmheg.c *//* * Copyright (C) 2005, Simon Kilvington * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA */#include <stdio.h>#include <stdint.h>#include <stdbool.h>#include <netinet/in.h>#include "carousel.h"#include "table.h"#include "assoc.h"#include "utils.h"/* Programme Association Table and Section */#define PID_PAT		0x0000#define TID_PAT		0x00/* Programme Map Section */#define TID_PMT		0x02/* stream_types we are interested in */#define STREAM_TYPE_VIDEO_MPEG2		0x02#define STREAM_TYPE_AUDIO_MPEG1		0x03#define STREAM_TYPE_AUDIO_MPEG2		0x04#define STREAM_TYPE_ISO13818_6_B	0x0b/* descriptors we want */#define TAG_LANGUAGE_DESCRIPTOR		0x0a#define TAG_CAROUSEL_ID_DESCRIPTOR	0x13#define TAG_STREAM_ID_DESCRIPTOR	0x52/* bits of the descriptors we care about */struct carousel_id_descriptor{	uint32_t carousel_id;};struct stream_id_descriptor{	uint8_t component_tag;};struct language_descriptor{	char language_code[3];	uint8_t audio_type;} __attribute__((__packed__));boolis_audio_stream(uint8_t stream_type){	switch(stream_type)	{	case STREAM_TYPE_AUDIO_MPEG1:	case STREAM_TYPE_AUDIO_MPEG2:		return true;	default:		return false;	}}/* * fills in a struct carousel based on the given service_id * returns a ptr to a static struct that will be overwritten be the next call to this routine */static struct carousel _car;struct carousel *find_mheg(unsigned int adapter, unsigned int timeout, uint16_t service_id, int carousel_id){	unsigned char *pat;	uint16_t section_length;	uint16_t offset;	uint16_t map_pid = 0;	bool found;	unsigned char *pmt;	uint8_t stream_type;	uint16_t elementary_pid;	uint16_t info_length;	uint8_t desc_tag;	uint8_t desc_length;	uint16_t component_tag;	/* carousel data we know so far */	snprintf(_car.demux_device, sizeof(_car.demux_device), DEMUX_DEVICE, adapter);	snprintf(_car.dvr_device, sizeof(_car.dvr_device), DVR_DEVICE, adapter);	_car.timeout = timeout;	_car.service_id = service_id;	/* unknown */	_car.carousel_id = 0;	_car.audio_pid = 0;	_car.audio_type = 0;	_car.video_pid = 0;	_car.video_type = 0;	_car.current_pid = 0;	/* map between stream_id_descriptors and elementary_PIDs */	init_assoc(&_car.assoc);	/* no PIDs yet */	_car.npids = 0;	_car.pids = NULL;	/* no modules loaded yet */	_car.got_dsi = false;	_car.nmodules = 0;	_car.modules = NULL;	/* get the PAT */	if((pat = read_table(_car.demux_device, PID_PAT, TID_PAT, timeout)) == NULL)		fatal("Unable to read PAT");	section_length = 3 + (((pat[1] & 0x0f) << 8) + pat[2]);	/* find the PMT for this service_id */	found = false;	offset = 8;	/* -4 for the CRC at the end */	while((offset < (section_length - 4)) && !found)	{		if((pat[offset] << 8) + pat[offset+1] == service_id)		{			map_pid = ((pat[offset+2] & 0x1f) << 8) + pat[offset+3];			found = true;		}		else		{			offset += 4;		}	}	if(!found)		fatal("Unable to find programme_map_PID for service_id %u", service_id);	vverbose("programme_map_PID: 0x%x", map_pid);	/* get the PMT */	if((pmt = read_table(_car.demux_device, map_pid, TID_PMT, timeout)) == NULL)		fatal("Unable to read PMT");	section_length = 3 + (((pmt[1] & 0x0f) << 8) + pmt[2]);	/* skip the program_info descriptors */	offset = 10;	info_length = ((pmt[offset] & 0x0f) << 8) + pmt[offset+1];	offset += 2 + info_length;	/*	 *  find the Descriptor Tags we are interested in	 */	while(offset < (section_length - 4))	{		stream_type = pmt[offset];		offset += 1;		elementary_pid = ((pmt[offset] & 0x1f) << 8) + pmt[offset+1];		offset += 2;		/* is it the default video stream for this service */		if(stream_type == STREAM_TYPE_VIDEO_MPEG2)		{			_car.video_pid = elementary_pid;			_car.video_type = stream_type;		}		/* read the descriptors */		info_length = ((pmt[offset] & 0x0f) << 8) + pmt[offset+1];		offset += 2;		while(info_length != 0)		{			desc_tag = pmt[offset];			desc_length = pmt[offset+1];			offset += 2;			info_length -= 2;			if(desc_tag == TAG_CAROUSEL_ID_DESCRIPTOR)			{				struct carousel_id_descriptor *desc;				desc = (struct carousel_id_descriptor *) &pmt[offset];				if(carousel_id == -1 || carousel_id == (ntohl(desc->carousel_id)))				{					_car.carousel_id = ntohl(desc->carousel_id);					add_dsmcc_pid(&_car, elementary_pid);					vverbose("pid=0x%x carousel_id=%u", elementary_pid, _car.carousel_id);				}			}			else if(desc_tag == TAG_STREAM_ID_DESCRIPTOR)			{				struct stream_id_descriptor *desc;				desc = (struct stream_id_descriptor *) &pmt[offset];				component_tag = desc->component_tag;				vverbose("pid=0x%x component_tag=0x%x", elementary_pid, component_tag);				add_assoc(&_car.assoc, elementary_pid, desc->component_tag, stream_type);			}			else if(desc_tag == TAG_LANGUAGE_DESCRIPTOR && is_audio_stream(stream_type))			{				struct language_descriptor *desc;				desc = (struct language_descriptor *) &pmt[offset];				/* only remember the normal audio stream (not visually impaired stream) */				if(desc->audio_type == 0)				{					_car.audio_pid = elementary_pid;					_car.audio_type = stream_type;				}			}			else			{				vverbose("pid=0x%x descriptor=0x%x", elementary_pid, desc_tag);				vhexdump(&pmt[offset], desc_length);			}			offset += desc_length;			info_length -= desc_length;		}	}	/* did we find a DSM-CC stream */	if(_car.npids == 0)		fatal("Unable to find Carousel Descriptor in PMT");	return &_car;}