Encoding EAC3

[DieHard]

I have read lots on how to convert/encode to AC3 which isn't difficult, however I haven't been able to find any real information on how to convert/encode to the EAC3 format. The reason I want to do this is simple: you need the audio to be in either DD+ or DTS-HD in order to use it as secondary audio for a PIP track. Other than using the Dolby Media Encoder which costs a bundle if you are only going to use it maybe a handful of times is there another way?

[nautilus7]

That's why there's not many programs you can use.

There is an experimental (E)-AC3 encoder here (http://sourceforge.net/project/showfiles.php?group_id=183195) (aften r733). While it's been very well known and good working for ac3 encoding, don't know it behaves with eac3. If not mistaken it can only encode to eac3 with a bitrate of 1024kbps.

[DieHard]

Does anyone know how to use the program properly? I tried using it to convert to EAC3 and when I check the Media Info it says it is an AC3+ file and everything, but when I try to load it into MUI Generator for Scenarist HDMV it gives me the error:

'ERROR: There is no mixing metadata for Secondary Audio. (mixmdate=0)'

[jruggle]

Does anyone know how to use the program properly? I tried using it to convert to EAC3 and when I check the Media Info it says it is an AC3+ file and everything, but when I try to load it into MUI Generator for Scenarist HDMV it gives me the error:

'ERROR: There is no mixing metadata for Secondary Audio. (mixmdate=0)'

That's good to know. This is the first error feedback I've gotten. The specs do not mention that mixing metadata is required and I don't know why Scenarist is finding "secondary audio"... but I will look into it.

Thanks,

[DieHard]

Actually, I haven't tried loading it into Scenarist as a normal Dobly Digital Plus (AC3+) file. I can try that later tonight and let you know if that works or not.

The reason it was saying that was because I was trying to load it in as Secondary Audio. The main point (for me at least) in wanting AC3+ is because it is one of only two formats, (it and DTS Express) that can be used as Secondary Audio for PIP which is what I really want at the moment.

[DieHard]

Ok, tried loading it into MUI Generator as a normal (primary) Dolby Digital Plus stream and got the error:

'ERROR: Error confirming E-AC3 strmtype as 01b (Type 1)'

So it seems it has different errors for trying to use it as primary and secondary audio. Personally my main objective is secondary audio but being able to convert my own audio to E-AC3 on either track and using it for my projects would be a big step in the right direction.

[bigotti5]

On Bluray DD+ is only supported for more than 5.1 channels - 5.1 channels shall be encoded as DD substream, channel 7,8 as DD+.

[DieHard]

So in order to get a valid DD+ stream you have to have at least 7.1 channels?

[bigotti5]

..more than 5.1

[DieHard]

I said 7.1 mainly because it is rare to see 6.1 tracks around anymore. Most tracks are recorded in 7.1 if they are more than 5.1.

Is there an easy way of converting a given track to more than 5.1? I tried through Sound Forge to do a 7.1 track but the AC3 Encoder won't allow more than 5.1 (since it doesn't seem to have a template for it) and almost no other formats do either. The only way I was able to save an 8 channel file was as a raw file, but then aften refuses to open the file for conversion. All I want to do is test whether a file greater than 5.1 would actually work after conversion or still give the same or different errors. If that would actually work then I could just add blank channels (or mixed channels) to whatever I want to use.

[jruggle]

Is there an easy way of converting a given track to more than 5.1? I tried through Sound Forge to do a 7.1 track but the AC3 Encoder won't allow more than 5.1 (since it doesn't seem to have a template for it) and almost no other formats do either. The only way I was able to save an 8 channel file was as a raw file, but then aften refuses to open the file for conversion. All I want to do is test whether a file greater than 5.1 would actually work after conversion or still give the same or different errors. If that would actually work then I could just add blank channels (or mixed channels) to whatever I want to use.
The regular AC3 format only supports up to 5.1 channels. This does not depend on the encoder, but on the actual format specification. E-AC3, on the other hand, supports more channels by adding what are called "dependent frames" carrying the extra channels, in between the normal 5.1 frames. The normal "independent" frames can be AC3 syntax or E-AC3 syntax, but the dependent frames must be E-AC3. However, for Blu-ray, the independent frames have to be normal AC3, not E-AC3. So it's odd. The experimental Aften patch does not yet support creating such streams... or even normal 7.1 E-AC3.

[DieHard]

Ak ok. It appears the only encoder to actually support those streams currently is the Dolby Media Encoder then. How hard do you think it will be to modify/patch Aften to actually allow usable E-AC3 streams? Seeing as the media info of the converted files actually show up as AC3+ it must be at least part of the way there.

[jruggle]

Ak ok. It appears the only encoder to actually support those streams currently is the Dolby Media Encoder then. How hard do you think it will be to modify/patch Aften to actually allow usable E-AC3 streams? Seeing as the media info of the converted files actually show up as AC3+ it must be at least part of the way there.

Shouldn't be terribly difficult. First step is 7.1 support (which will require proper channel reordering). Then add option to use plain AC3 for the first 6 channels. But I don't have lots of free time now, so unless someone else does this it may be a while.

[DieHard]

No worries. I can wait. It isn't the biggest thing in the world, just would be nice to test a fully working async PIP platform since as of yet I haven't seen one on a commercial disc. I may end up stripping an EAC3 or DTS Express channel out of another disc and using it with my async PIP secondary video stream just to check how it works (and if it works properly). If that then works well, then I know what to expect and can eagerly await a working version of aften. ;-)