Are there different types of AC3 5.1?

[naskad]

Wonder if anyone can help me with this...

My receiver only play AC3 and DTS, but not AAC sound. It plays AC3 5.1 and DTS beautifully.

Some videos that I have come with AAC 5.1 sound, so I converted the sound to AC3 5.1 using SUPER software.

The problem is, my receiver does not recognised the converted sound as Dolby Digital 5.1. It only plays with 2 channel stereo.

I checked the file with Mediainfo and it is AC3 5.1.

Now I'm confused. How is it that AC3 that originally comes with with the video file plays perfectly, but not the converted AC3? Are there different types of AC3 that I should know?

[naskad]

I forgot to mention that the file is MKV AAC 5.1 and I converted it to MKV AC3 5.1 using eRightSoft SUPER.

[leghorn]

Maybe it's still AAC but with AC3 header...

[El Heggunte]

Yes, 5.1 AC3 may mean different things --- it can encoded at 384kbps, or at 448kbps, or at 576kbps, or at 640kbps.

Also, it can be either big-endian ot little-endian.

Bottom-line is, do NOT use SUPER, case solved.

[naskad]

OMG, all my mkv files with AAC I converted with SUPER to MKV AC3.

El Heg, all conversion I used 440kbps. So, isn't there any way to switch this "big-endian or little-endian" thing?

I've already deleted the original MKV AAC files... stupid me

[naskad]

Leghorn.... is there really such thing as AAC with AC3 header? Sorry for being such a newbie ...

[jagabo]

How many channels does MediaInfo report? Import the audio into Audacity. Do you get six channels?

[naskad]

MediaInfo reports that the file has 6 channels. That's why I'm stumped. I'll try to see it in Audacity...

[naskad]

Well, I extracted the ac3 file and imported it into Audacity. It shows 6 channels...

Somebody suggested a software called Mp42Mkvac3. I'm going to try it next.

[jagabo]

From where is your receiver getting the AC3 audio? Maybe that source device is down-mixing to stereo.

[naskad]

jagabo, I don't think so. The file is mp4 AAC5.1 which I downloaded from a torrent. I've checked with Mediainfo and GSpot and it is with 6-channel audio. So I converted to mkv AC35.1 with eRightSoft Super. But my receiver doesn't recognised it and plays it as 2 channel stereo.

Maybe El Heggunte is right.. Super is not a good converter and I shouldn't use it.

I'm yet to try Mp42Mkvac3... been away for a couple of days. I'll get to it soon and report it here.

[jagabo]

jagabo, I don't think so. The file is mp4 AAC5.1 which I downloaded from a torrent. I've checked with Mediainfo and GSpot and it is with 6-channel audio. So I converted to mkv AC35.1 with eRightSoft Super. But my receiver doesn't recognised it and plays it as 2 channel stereo.

What are you using to play the MKV file? Ie, how is the AC3 audio in the MKV file getting to your receiver? I was suggesting that device/software may be downmixing AC3 5.1 to stereo before sending it to the receiver. Many players, both hardware and software can do that.

[naskad]

jagabo, I don't think it's the fault of the player, because other files already with AC35.1 are recognised by the receiver. It's only files that I converted with SUPER from AAC to AC3 that's problematic.

[naskad]

I have tried Mp42Mkvac3 and it works.... Now my receiver recognises the audio as AC3 6 channels. So it's confirmed that eRightSoft Super is not doing the conversion properly.