Dolby Digital over SPDIF, sometimes works, sometimes not? (1 Viewer)

[vl002001]

I'm new to the audio side of things, but right now I'm using ffdshow to passthough ac3 to my HK avr235 receiver.
Sometimes, (for instance with Windows Media Center or certain x264 movies), the receiver says "DOLBY DIGITAL" and I won't be able to adjust any settings. I figure because the sound coming in is 5.1 and the receiver doesn't need to upconvert anything.

However, other times, usually older xvid files with dd5.1 sound, it says DOLBY PRO LOGIC II, which i assume means the receiver is upconverting the signal to 5.1 sound. However, isn't the sound already 5.1? is it over processing the sound? I only ask because the surround sound sounds pretty crappy when it does this. However, when it gets a mp3 2.0 file, and then processes it using dolby pro logic ii, it actually sounds much better.

Any ideas? I'm obviously very new to this, thanks.

 

[doornjoostje]

Try SAF 5.0

 

[Owlsroost]

AC3/Dolby Digital can be anything from mono (1.0) to stereo (2.0) to 5.1 channel, and it can be flagged as prefering Dolby Pro-logic post-processing e.g. for 2.0 streams.

So your receiver is probably just doing what the 'metadata' in the stream is suggesting.....

Tony

 

[vl002001]

Fixed the problem, in case anybody ever has a similar one: I used the media portal codec for AC3 and set it to passthrough. For some reason, this codec does passthrough fine, while ffdshow only passed through AAC.

Anyway, it's working great now. Thanks for the consideration.

 

[hoborg]

vl002001
..."while ffdshow only passed through AAC"

You cannot passthrough AAC. FFDShow reencode it to AC3 "on the fly" and passthrough it.