Janne Grunau wrote: > On Tuesday 18 September 2007 01:41:04 Manu Abraham wrote: >> Johannes Stezenbach wrote: >>> On Tue, Sep 18, 2007 at 02:50:09AM +0400, Manu Abraham wrote: >>>> Johannes Stezenbach wrote: >>>>> The recording filters are exactly the piece from V4 which has the >>>>> "mmap DMA buffers" zero copy API. But to be honest, I don't think >>>>> it's important on a PC which can copy > 1GByte/s in RAM. More >>>>> interesting would be the ability to have multiple independant >>>>> filtered TS outputs instead of just one dvr device. >>>> Currently have you tried playing back a High Bit rate H.264 stream >>>> default of a DVB-S2 stream ? I guess not. >>>> >>>> If you have had, you will see my reasons why i am trying to >>>> optimize the overheads. >>>> BTW: it is not RAM that matters here, but CPU horsepower >>> A demux doesn't decode, and what matters is memory bandwidth. >> Try running a software decoder alongwith and tell me that that >> decoding doesn't need CPU > > right the software decoder needs cpu power. > >> and then the options what you can look at >> is cutting whatever overheads it is. > > Wrong, you would start optimizing parts with take significant time. I > can record 20mbps streams on a machine capable of decoding H264 1080p > video with more than 99 percent idle. So even if you can optimize > capturing the stream to taking zero cpu cycles (and you can't) you will > see at most 1% increase in decoding speed. The case of a 20Mbps stream getting recorded is not a great thing. when you have a TS with symbol rate 27.5Msps, (capturing the complete TS) the normal TS itself is about 27Mbps (in a very crude rounded off case) So, the situation that you have isn't larger than a situation having a normal single DVB-S card. _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
