Question about SPDIF passthrough on AC3FILTER.

I'm using ac3filter to passthrough 5.1 audio to my receiver via HDMI. But the SPDIF status is "AC3 encode" instead of "SPDIF passthrough" :

Input format: PCM Float 5.1 (back) 48000
User format: PCM16 5.0 0
Output format: SPDIF 5.0 48000

Use SPDIF
SPDIF status: AC3 encode
SPDIF passthrough for: AC3 DTS
Use AC3 encoder (encode stereo PCM)
Check SPDIF sample rate (allow: 48kHz)
Query for SPDIF output support

And when i uncheck "USE AC3 ENCODER" BOX, all the sound go off. what should i do now? I just want to passthrough audio to receiver.

If the input is PCM it means another filter is doing the decoding. Either disable that filter, or enable bitstreaming in that filter.

Which player are you using?

I am using the included player in the pack which is Media classic player.

On the "system" tab in AC3Filter settings, enable AC3/DTS and disable PCM.

During playback you can see which filters are used by looking at:
Menu > Play > Filters

After disabled some filter, the input now is 'AAC 5.1'. But the SPDIF STATUS is STILL : AC3 ENCODE, why its still not 'passthrough'? :
Input format: AAC 5.1 48000
User format: PCM16 5.1 0
Output format: SPDIF 5.1 48000

Use SPDIF
SPDIF status: AC3 encode
 SPDIF passthrough for: AC3 DTS
 Use AC3 encoder (do not encode stereo PCM)
 Do not check SPDIF sample rate
 Query for SPDIF output support

By the way, thank you for your help so far

Passthrough only works with specific audio formats. AAC is not one of them.

My advice is to disable the AC3 encoder. Then it will send PCM (= uncompressed) audio to your receiver. That should work fine with HDMI. The loss of sound that you had before, is most likely because you need to restart the player after changing the setting for thing to work correctly.

Its all good now. I disabled the AC3 encoder, restart MCP, and it work perfectly now. Thank you so much....