[linux-dvb] DVB file formats

Marcus Metzler mocm at mocm.de
Thu Jun 16 14:06:55 CEST 2005


>>>>> "Andrew" == Andrew de Quincey <adq_dvb at lidskialf.net> writes:

    Andrew> On Thursday 16 June 2005 12:42, Johannes Stezenbach wrote:
    >> Andrew de Quincey wrote: > BTW: I was thinking last night. Do
    >> we actually need to know all the PMT > entries for the
    >> services.
    >> >
    >> > On the sample for a channel, I have: > es = <pid> <type>
    >> [<language>] [pcr] > ...
    >> >
    >> > Where I was expecting there to be a line for each entry in
    >> the PMT.
    >> >
    >> > However, the only reason for having this information is to
    >> speed up lock > times. We don't actually need information on
    >> _every_ ES - just the last > audio/video ES that the user
    >> selected. The rest can be pulled from the > PMT once the
    >> channel is up and running. Comments?
    >> 
    >> You need he pcr pid, too, but other pids are superflous for
    >> fast zapping (well, maybe + ac3 pid).

    Andrew> Ah k, have added the PCR PID.

    Andrew> Wouldn't the AC3 pid be the same as the audio PID though? 
    Andrew> I mean - the user wouldn't want to play a non-AC3 audio
    Andrew> stream AND an ac3 stream at the same time?

Yes, but there are significant differences in terms of the PMT and the
PES format concerning AC3 and normal MPEG sound, also an application
has to aware of it because of the difference in codecs (not to mention
licenses :)) needed. 

Marcus

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| Dr. Marcus O.C. Metzler        |                                   |
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