On Sun, 2010-02-07 at 21:36 +0100, Lars Hanisch wrote: > Hi, > > Just for completeness, attached is the patch against the subversion > repository at ivtvdriver.org.
Thanks! Regards, Andy > Regards, > Lars. > > Am 04.02.2010 08:25, schrieb Hans Verkuil: > > On Thursday 04 February 2010 04:16:03 Andy Walls wrote: > >> On Thu, 2010-02-04 at 01:18 +0100, Lars Hanisch wrote: > >>> Hi, > >>> > >>> I'm writing some code repacking the program stream that ivtv delivers > >>> into a transport stream (BTW: is there existing code for this?). > >> > >> Buy a CX23418 based board. That chip's firmware can produce a TS. > >> > >> I think Compro and LeadTek cards are available in Europe and are > >> supported by the cx18 driver. > >> > >>> Since > >>> many players needs the PCR I would like to use the SCR of the PS and > >>> place it in the adaption field of the TS (if wikipedia [1] and my > >>> interpretation of it is correct it should be the same). > >>> > >>> I stumbled upon the ps-analyzer.cpp in the test-directory of the > >>> ivtv-utils (1.4.0). From line 190 to 198 the SCR and SCR extension are > >>> extracted from the PS-header. But referring to [2] the SCR extension has > >>> 9 bits, the highest 2 bits in the fifth byte after the sync bytes and > >>> the lower 7 bits in the sixth byte. The last bit is a marker bit (always > >>> 1). > >>> > >>> So instead of > >>> > >>> scr_ext = (hdr[4]& 0x1)<< 8; > >>> scr_ext |= hdr[5]; > >>> > >>> I think it should be > >>> > >>> scr_ext = (unsigned)(hdr[4]& 0x3)<< 7; > >>> scr_ext |= (hdr[5]& 0xfe)>> 1; > >> > >> > >> Given the non-authoritative MPEG-2 documents I have, yes, you appear to > >> be correct on this. > >> > >> Please keep in mind that ps-analyzer.cpp is simply a debug tool from an > >> ivtv developer perspective. You base prodcution software off of it at > >> your own risk. :) > >> > >>> And the bitrate is coded in the next 22 bits, so it should be > >>> > >>> mux_rate = (unsigned)(hdr[6])<< 14; > >>> mux_rate |= (unsigned)(hdr[7])<< 6; > >>> mux_rate |= (unsigned)(hdr[8]& 0xfc)>> 2; > >>> > >>> Am I correct? > > > > Yes, you are correct. I miscounted the bits when I wrote this originally. > > Thanks for reporting this! > > > > Regards, > > > > Hans > > > >> > >> I did not check this one, but I would not be surprised if ps-analyzer > >> had this wrong too. > >> > >> Regards, > >> Andy > >> > >>> Regards, > >>> Lars. > >>> > >>> [1] http://en.wikipedia.org/wiki/Presentation_time_stamp > >>> [2] http://en.wikipedia.org/wiki/MPEG_program_stream > >>> -- > >> > >> > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-media" in > >> the body of a message to majord...@vger.kernel.org > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > >> > >> > > > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
