Re: MPEG-2 Capture?
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From: Dan D. <dde...@co...> - 2001-02-06 17:49:15
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From: "Aleksandr Milewski" <n6...@mi...> > At 1:03 AM -0500 on 2/6/01, Dan Dennedy commanded the electrons to > create a missive titled "Re: MPEG-2 Capture?": > |Aleksandr Milewski wrote: > |> > |> Has anyone done any work on MPEG-2 capture from 1394? > | > |Not that we are aware of. Most us are capturing DV and uncompressed > |video. > > Uncompressed? From what source? Mostly closed circuit CCD-type Sony cameras for machine vision and industrial applications. However, several people have the Orange Micro iBot or Pyro WebCam cheap desktop cameras. > |> I admit that I haven't built linux1394 yet, so if this is as simple as > |> > |> cat /dev/video1394 >> file.mpeg > | > |Not that simple until someone brings video1394 up to video4linux > |compliancy. However, you can certainly call a few ioctls and dump the > |iso packets to disk. If it is that braindead, then maybe it will be as > |simple as that, but I would not be so optimistic. > > I'm reasonably sure it is that braindead. According to one source, > each iso packet contains either one or two 188-byte Mpeg2 TS packets, > "with header and timestamp." Sounds braindead to me. Well, then I strongly recommend the libraw API's functions as video1394 is rather tricky when dealing with variable-size packets because packets will split across the boundaries of the buffers. > In any case... > > At 1:18 AM -0500 2/6/01, Dan Dennedy wrote: > |Also, you could just use libraw's iso read functions. It is more > |universal, popular and simple. You can view the source of dvgrab to see > |how to use it. Access dvgrab at http://www.schirmacher.de/arne/dvgrab/. > > This is the right thing to do. I'll look at the source, but I have a > suspicion that commenting out large pieces of dvgrap might be the way > to go. There is a test mode of dvgrab and corresponding function that you should look at for the case that is closest to yours. > Of course, the reason I asked this on the user list is that I'm far > more user than developer, so if someone would like to lead the way... The IEC-61883-4 spec describes MPEG2-TS over 1394. Can you confirm that your device conforms with this? The spec description says it is related to DVB, in which case one should look strongly at the DVB API and source code at http://www.linuxtv.org/. What devices support this that might convince me to buy one--a digital TV? > -Zandr > -- > --------------------------------------------------------------------- > Aleksandr Milewski N6MOD > n6...@mi... http://www.milewski.org/ > > _______________________________________________ > mailing list Lin...@li... > http://lists.sourceforge.net/lists/listinfo/linux1394-user > |