Chun Chung Lo wrote: > Hi all, > > I am now using a STB (under development) which its hardware > configuration is: > > SAA7134 + TDA10046A + TD1316 > > When I capture the TS stream (which is stream out by a DVB-T modulator), > and compare the file with the original one, I found tones of NULL > packets (which its header is 0x47 0x1F, 0xFF 0x10, and remains are 0x00 > ... Until the end of a TS packets, 188bytes). > > The captured TS is corrupted in a random level, sometimes seriously, > sometimes a bit. > > I found these null packets wasted lots of PCI bandwidth and, may these > cause the above error? > > And where are the TS null packets come from?
hi, usually, the DVB-T modulator fills the outgoing modulated TS with null PIDs when the bitrate of the incoming TS is lower then the expected outgoing bitrate. +----------+ +----------------+ | |ASI| | UHF | TS player|---| DVB-T modulator|----- | | IN| | OUT +----------+ +----------------+ with expected i mean the useful bitrate that comes from the other parameters you put in the DVB-T modulator: - channel BW (7/8 MHz) - FEC - guard interval - modulation (QPSK/QAM16/QAM64) there are preformatted tables about it on the net. then you should look at the TS player, you are using; it's feeding the modulator at a constant bit rate (CBR) or it follows the PCR? but you need to detail more thoroughly your setup if you want us to better understand what's going on. anyway, i really don't know how it can be corrupted bye andrea venturi _______________________________________________ linux-dvb mailing list linux-dvb@linuxtv.org http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
