Re: TV stream and scrambled channels

Peter Feldbaumer wrote:
I'd guess it depends on the actual implementation... The better definition for what I meant with hw-demux should be "hw-packet-filter" - it shouldn't care about the contents of single packets at all - the more "high-level" the functions of the demuxer get (e.g. attaching time-stamps to samples, rebuilding complete pes-packets...) the more likely they will fail, since informations of the _descrambled_ stream are needed for this kind of operation.
If your hw-device tries to perform such high-level operations, it will most likely discard all packets it can't understand (because they're scrambled) - if it simply outputs packets with pid x on pin x and packets with pid y on pin y then it should work.

May I ask what kind of device/card you have that you think performs hw-mpeg2-decoding?

Actually I don't have a hw-decoder tuner. Just thinking ahead... :-)

Most likely this is implemented with no graph at all (e.g. technotrend dvb-s _premium_ only exposes a custom sdk, no bda-drivers).
If anything at all, it would work with some kind of overlay-surface (where the decoded video-frames get copied to the graphics-card directly) - I personally have never seen a bda-capture-filter output pin with anything but a full (or partial) mpeg2-ts - any decoded output-pin would present a _massive_ load on the system, since you constantly would have to transfer 768x576x24Bitx25fps = 32MB/s from your pci-card or usb-device... If at all it can only work by using direct-memory transfer to the graphics-card. Then the components of the graph should be "wrapped" in dummy directshow-filters, presenting a "regular" graph to the system, but the actual samples (bytes) never leave the card - with such a graph you also won't be able to insert the sample-grabber or a custom-transform filter into the graph.

Ok, that makes sense!

Thanks a lot for all your help Peter, your input has been extremely valuable!

Best regards
/ David Olsson
.

Relevant Pages

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