Hi, Thanks! You are right. The model of the modulator is PROMAX MO-170. It can be configured to Master mode (with null packet stuffing) and Slave mode (without null packet stuffing). But I am not sure how to make it to operate in Slave mode. I also found the player is operating follows the PCR. I see there is a CBR can be set, but when I set, the modulator reports it cannot lock the signal (or frequency?). Please help. Thanks. Best regards, Lo Chun Chung -----Original Message----- From: Andrea Venturi [mailto:a.venturi@xxxxxxxxx] Sent: Tuesday, 03 October, 2006 5:29 PM To: Chun Chung Lo; linux-dvb@xxxxxxxxxxx Subject: Re: TS Stream - null packets generation? 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 This message (including any attachments) is for the named addressee(s)'s use only. It may contain sensitive, confidential, private proprietary or legally privileged information intended for a specific individual and purpose, and is protected by law. If you are not the intended recipient, please immediately delete it and all copies of it from your system, destroy any hard copies of it and notify the sender. Any use, disclosure, copying, or distribution of this message and/or any attachments is strictly prohibited. _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
