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Implement 8/30 format 1 teletext packet decoding

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It contains network id, network name, current date and time.

patch from Otvos Attila oattila at chello dot hu



git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@24252 b3059339-0415-0410-9bf9-f77b7e298cf2
This commit is contained in:
voroshil 2007-08-28 02:37:48 +00:00
parent ce59c5e847
commit fb7d88d344
2 changed files with 85 additions and 0 deletions
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1
stream/tv.h
View File

@ -204,6 +204,7 @@ typedef struct {
#define TV_VBI_CONTROL_START 0x554 ///< vbi start
#define TV_VBI_CONTROL_STOP 0x555 ///< vbi stop
#define TV_VBI_CONTROL_DECODE_PAGE 0x556 ///< decode vbi page
#define TV_VBI_CONTROL_GET_NETWORKNAME 0x557 ///< get current network name
int tv_set_color_options(tvi_handle_t *tvh, int opt, int val);
int tv_get_color_options(tvi_handle_t *tvh, int opt, int* val);

84
stream/tvi_vbi.c
View File

@ -140,6 +140,14 @@ typedef struct {
tt_page** ptt_cache;
unsigned char* ptt_cache_first_subpage;
/// network info
unsigned char initialpage;
unsigned int initialsubpage;
unsigned int networkid;
int timeoffset; // timeoffset=realoffset*2
unsigned int juliandate;
unsigned int universaltime;
unsigned char networkname[21];
} priv_vbi_t;
static unsigned char fixParity[256];
@ -462,6 +470,10 @@ static void clear_cache(priv_vbi_t* priv){
free(tp);
}
}
priv->initialsubpage=priv->networkid=0;
priv->timeoffset=0;
priv->juliandate=priv->universaltime=0;
memset(priv->networkname,0,21);
}
/**
@ -905,6 +917,73 @@ static int decode_pkt0(priv_vbi_t* priv,unsigned char* data,int magAddr)
return 1;
}
/**
* \brief decode teletext 8/30 Format 1 packet
* \param priv private data structure
* \param data raw teletext data (with not applied hamm correction yet)
* \param magAddr teletext page's magazine address
*
* \remarks
* packet contains:
* 0 designation code
* 1..2 initial page
* 3..6 initial subpage & magazine address
* 7..8 network id
* 9 time offset
* 10..12 julian date
* 13..15 universal time
* 20..40 network name
*
* First 7 bytes are protected by Hamm 8/4 code.
* Bytes 20-40 has odd parity check.
*
* See subcaluse 9.8.1 of specification for details
*/
static int decode_pkt30(priv_vbi_t* priv,unsigned char* data,int magAddr)
{
int d[8];
int i,err;
for(i=0;i<7;i++){
d[i]= corrHamm48[ data[i] ];
if(d[i]&0x80){
pll_add(priv,2,4);
return 0;
}
d[i]&=0xf;
}
err=0;
for(i=20; i<40; i++){
data[i]= fixParity[data[i]];
if(data[i]&0x80)//Unrecoverable error
err++;
pll_add(priv,1,err);
}
if (err) return 0;
if (d[0]&0xe) //This is not 8/30 Format 1 packet
return 1;
priv->initialpage=d[1] | d[2]<<4 | (d[6]&0xc)<<7 | (d[4]&1)<<8;
priv->initialsubpage=d[3] | d[4]<<4 | d[5]<<8 | d[6]<<12;
priv->networkid=data[7]<<8 | data[8];
priv->timeoffset=(data[9]>>1)&0xf;
if(data[9]&0x40)
priv->timeoffset=-priv->timeoffset;
priv->juliandate=(data[10]&0xf)<<16 | data[11]<<8 | data[12];
priv->juliandate-=0x11111;
priv->universaltime=data[13]<<16 | data[14]<<8 | data[15];
priv->universaltime-=0x111111;
snprintf(priv->networkname,21,"%s",data+20);
return 1;
}
/**
* \brief decode packets 1..24 (teletext page header)
* \param priv private data structure
@ -1126,6 +1205,8 @@ static void vbi_decode(priv_vbi_t* priv,unsigned char*buf){
}else if(pkt>0 && pkt<VBI_ROWS){
if(!priv->mag[magAddr].pt) continue;
decode_pkt_page(priv,data+2,magAddr,pkt);//skip MRGA
}else if(pkt==30){
decode_pkt30(priv,data+2,magAddr);
} else {
mp_msg(MSGT_TV,MSGL_DBG3,"unsupported packet:%d\n",pkt);
}
@ -1393,6 +1474,9 @@ int teletext_control(void* p, int cmd, void *arg)
prepare_visible_page(priv);
*(void **)arg=priv->display_page;
return TVI_CONTROL_TRUE;
case TV_VBI_CONTROL_GET_NETWORKNAME:
*(void **)arg=priv->networkname;
return TVI_CONTROL_TRUE;
}
return TVI_CONTROL_UNKNOWN;
}