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AC3+ passthrough possible?

DM8000

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#1 macnuts

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Posted 21 July 2011 - 12:45

I have the DM8000 (genuine) connected to the amplifier with optical cable. The amplifier is capable of playing AC3+ (Dolby Digital Plus) source. The DM8000 has two embedded DVB-S2 tuners and one Philips TU1216 DVB-T tuner.

The provider of DVB-T content added the AC3+ sound track to one of its services. The service has three sound tracks, MPEG, AC3 and AC3+ now. The DM8000 recognizes them correctly; I can confirm it after pressing the yellow button. The audio pids are OK too. Also, the bitrate plugin reports OK on any (MPEG/AC3/AC3+) sound track. I have the AC3 downmix disabled.

However, when I switch to the AC3+ no sound is passed to the amplifier. I can guess it from the mute button behavior: I get the feedback from the amplifier (on its display) when I press the mute button on the DM remote while MPEG/AC3 sound is selected; when I do the same when AC3+ is selected I get nothing from the amplifier.

Is it any chance to "force" the DM8000 to pass through the AC3+ stream? I think that passing through the stream does not require any AC3+ license? But I can be wrong about that.

Re: AC3+ passthrough possible? #2 pieterg

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Posted 21 July 2011 - 14:30

I guess the dm8k drivers do not recognise the ac3+ codec, therefore they do not enable the passthrough mode (even though passthrough would probably have worked, without having the ac3+ license)

Re: AC3+ passthrough possible? #3 macnuts

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Posted 21 July 2011 - 14:41

You are probably right.

I got the following dmesg ouput while switching audio to AC3+ (line 3 is of special interest here):
start audio on dmx 0 pid:6c
audio xpt start
unsupported audio bypass type 34
audio: decoder start 0
audio delay 18000 (200 ms)
total video delay: 18000 (200 ms)
ch0: lock
ch0: lock
RAP first pts 0x179edaa4e, stc 0x179eda572, pcr valid
RAP sampling rate info isr


Re: AC3+ passthrough possible? #4 macnuts

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Posted 21 July 2011 - 15:11

Line 3 comes from bcm7400.ko, so indeed dm8k drivers are to blame.
Thanks for response anyway.

Re: AC3+ passthrough possible? #5 Jeroensky

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Posted 22 July 2011 - 16:26

How about posting it on Dream Multimedia forum (or contact them), what is the response of Dream Multimedia themselves?

Dreambox Dm8000 with all hardware addons donated to OpenPli. No interests anymore in policy of CanalDigitaal / M7 group and now-a-days channel encryption (like CI+ / HD+).

Good luck Enigma2 / OpenPli, it was fun with Sky Movies and so on, collected a nice collection of movies. Now back to basic boring lineair TV with KPN iTV (VDSL2 pair bonding 219 / 63 Mbps).

The VDSL pair bonding is excellent for... torrents to NAS in higher quality then HDTV (Like Dolby-TrueHD or DTS-Master-Audio soundquality ) :D


Re: AC3+ passthrough possible? #6 macnuts

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Posted 22 July 2011 - 19:31

Yes, that will be my next step. I will report about the progress, if any.

Re: AC3+ passthrough possible? #7 Jeroensky

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Posted 23 July 2011 - 09:11

They have money for AC3+ license don't you agree. I mean they sell DM8000 pvr's /images/smiley/grin.gif

To Openpli. If they add AC3+, is their a way to add functionality to convert in realtime AC3+ to AC3 output on sp/dif with keeping the 5.1 channels?
My amp supports DTS & AC3 only, has no AC3+ decoders onboard. (and no i'm not going to buy a amp with the newer codecs, this one works fine. Would be nice if a multichannel amplifier has sort of opensource software on board, so that 4 ecxample extra audio related functionality can be added, like extra codecs. So bigger cpu instead of multimediachip that has fixed decoders).

Dreambox Dm8000 with all hardware addons donated to OpenPli. No interests anymore in policy of CanalDigitaal / M7 group and now-a-days channel encryption (like CI+ / HD+).

Good luck Enigma2 / OpenPli, it was fun with Sky Movies and so on, collected a nice collection of movies. Now back to basic boring lineair TV with KPN iTV (VDSL2 pair bonding 219 / 63 Mbps).

The VDSL pair bonding is excellent for... torrents to NAS in higher quality then HDTV (Like Dolby-TrueHD or DTS-Master-Audio soundquality ) :D


Re: AC3+ passthrough possible? #8 pieterg

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Posted 23 July 2011 - 10:24

that conversion will have to be done in hardware



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