[matto]

Hello forum,

I'm not sure whether this is a bug, an unimplemented feature, or whether XBMC is just not designed to work this way, but I can't get Dharma's Smoothvideo to work with anything other than stereo sound. By Smoothvideo, I am referring to activating System setting > Video > Playback > Sync playback to display. I am using the A/V sync method "Video clock (resample audio)". My goal is to get movies, generally at 23.97fps, to play back synchronised to a 50Hz / 720p PAL TV (i.e 2x25fps), by speeding up the video by 4.3%. This works perfectly with movies that only have stereo soundtracks, or with multichannel soundtracks when I set Settings > Audio Output to use a 2.0 speaker config and turn off the AC3 / DTS capable receiver option (i.e. forcing XBMC to mix-down to PCM).

I understand that packetised streams like AC3 can't be sped up or down without decoding the audio first, stretching it, and re-encoding it to AC3. I was hoping, however, that now XBMC has a built-in AC3 encoder, it would be possible. When I used a PC HTPC, I had a set up that went: 24fps movie with AC3/DTS -> MPC-HC -> 6x PCM -> ReClock 1.8 (built-in AC3 encoder) -> 25fps movie with AC3, and it worked beautifully, so it's certainly possible.

Does anyone know how to get this working in Dharma? Is there a problem with the beta version? Will it be fixed / added later?

I am using a 2009/9400m Mac mini, OS 10.6.4 and XBMC rev 33324 Dharma beta 1. The TV is a Samsung plasma, without 24p support, connected via a DVI - HDMI cable. Audio is through an optical cable, to an amp that supports AC3 and DTS.

Many thanks to the developers of this great application (been using it since Xbox), and thanks for reading through this long post.

Matt

[bobo1on1]

It simply isn't implemented yet, the audioengine branch will probably fix that.

[snowdrift]

It simply isn't implemented yet, the audioengine branch will probably fix that.

Awesome! I look forward to that.

I do pretty much the same thing as matto with smoothvideo and would also be interested in getting multichannel audio out rather than stereo...just to give me an excuse to go out and get a home cinema amp

[matto]

Thanks bobo1on1 for the quick response. Perhaps I may ask a couple more questions.

Is the audioengine functionality just weeks away, or will it likely take many months / the next major release before it arrives?

Secondly, if using an external USB soundcard, could the AC3 / DTS stream be decoded and stretched, then just output from analogue connections? I only required re-encoding to use the mini's SPDIF output. I had thought of doing this before, but IIRC there was a problem with different surround sound formats having different channel mappings, making it very fiddly to live with in practice.

[bobo1on1]

Audioengine will be done when it's done, it's hard to make a schedule when people are doing this in their spare time.

Analog audio works fine with the resample sync method, it also works with pcm over hdmi and pcm over spdif, the only thing that doesn't work is passthrough over spdif or hdmi.