REBVAL *N_watch(REBFRM *frame, REBVAL **inter_block)
{
WatchVar = Get_Word(FRM_ARG1(frame));
Watcher = VAL_SERIES(WatchVar);
SET_INTEGER(FRM_ARG1(frame), 0);
return Nothing;
}
/* parse system layer, ignore everything we don't need */
void Next_Packet()
{
unsigned int code;
int l;
for(;;)
{
code = Get_Long();
/* remove system layer byte stuffing */
while ((code & 0xffffff00) != 0x100)
code = (code<<8) | Get_Byte();
switch(code)
{
case PACK_START_CODE: /* pack header */
/* skip pack header (system_clock_reference and mux_rate) */
ld->Rdptr += 8;
break;
case VIDEO_ELEMENTARY_STREAM:
code = Get_Word(); /* packet_length */
ld->Rdmax = ld->Rdptr + code;
code = Get_Byte();
if((code>>6)==0x02)
{
ld->Rdptr++;
code=Get_Byte(); /* parse PES_header_data_length */
ld->Rdptr+=code; /* advance pointer by PES_header_data_length */
//printf("MPEG-2 PES packet\n");
return;
}
else if(code==0xff)
{
/* parse MPEG-1 packet header */
while((code=Get_Byte())== 0xFF);
}
/* stuffing bytes */
if(code>=0x40)
{
if(code>=0x80)
{
fprintf(stderr,"Error in packet header\n");
exit(1);
}
/* skip STD_buffer_scale */
ld->Rdptr++;
code = Get_Byte();
}
if(code>=0x30)
{
if(code>=0x40)
{
fprintf(stderr,"Error in packet header\n");
exit(1);
}
/* skip presentation and decoding time stamps */
ld->Rdptr += 9;
}
else if(code>=0x20)
{
/* skip presentation time stamps */
ld->Rdptr += 4;
}
else if(code!=0x0f)
{
fprintf(stderr,"Error in packet header\n");
exit(1);
}
return;
case ISO_END_CODE: /* end */
/* simulate a buffer full of sequence end codes */
l = 0;
while (l<2048)
{
ld->Rdbfr[l++] = SEQUENCE_END_CODE>>24;
ld->Rdbfr[l++] = SEQUENCE_END_CODE>>16;
ld->Rdbfr[l++] = SEQUENCE_END_CODE>>8;
ld->Rdbfr[l++] = SEQUENCE_END_CODE&0xff;
}
ld->Rdptr = ld->Rdbfr;
ld->Rdmax = ld->Rdbfr + 2048;
return;
default:
if(code>=SYSTEM_START_CODE)
{
/* skip system headers and non-video packets*/
code = Get_Word();
ld->Rdptr += code;
}
else
{
fprintf(stderr,"Unexpected startcode %08x in system layer\n",code);
exit(1);
}
break;
}
}