Making the driver work 'non-blocking' with PES

[Marcus O.C. Metzler <mocm@netcologne.de>]

Klaus Schmidinger writes:
 > I am currently struggling to make the DVB driver work with
 > non-blocking mode when replaying PES. However, my efforts
 > so far haven't resulted in a working solution :-(
 > 
The problem with non-blocking and pes playback is the conversion from
PES to AV_PES in the driver. We are currently changing the firmware,
so that it will send and accept PES instead of AV_PES. After that
there will be no more AV_PES, but non-blocking shouldn't be a problem.
Currently, it is not easy to predict how much free buffer space you
need for the incoming PES after the conversion. When the converted
packet reaches the point where it is written to the firmware and it is
realized that it can't all be written, you would have to tell the
application that x bytes were written and discard the ones that could
not be written. But you really would really have to translate it back
into PES in order to see what the right x value is and you would also
have to "turn" back the translation process to that point. This is not
that easily done. At least not as easily as switching the firmware to
PES.

Another solution would be to estimate the amount of data that can be
written to the firmware after the translation before the translation
starts and reject any surplus. That would be rather crude and waste
time and resources, but could be done. I haven't looked at Klaus
patch, yet, so I don't know how he tries to fix it.

I'll see what can be done. Have a look at the CVS, I 'll check in a
knew driver, if and when I find a good solution.

Marcus

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Dr. Marcus Metzler                             
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