eac3to - audio conversion tool

[videoh]

Originally Posted by stax76

Except the FLAC format.

FLAC is easy to cut with sox.exe. Use the trim effect.

[orion44]

Can "-ac 2" switch in ffmpeg be used to downmix 7.1 DTS audio to stereo WAV?

Or is that switch just used for 5.1 AC3 to stereo downmixing?

[Sparktank]

Originally Posted by orion44

Can "-ac 2" switch in ffmpeg be used to downmix 7.1 DTS audio to stereo WAV?

Yes, but I don't know which switch it is to normalize if clipping goes beyond 0dBFS.

I'd use eac3to for that:

eac3to source.dts stereo.wav -downStereo -normalize

It should normalize if clipping beyond 0dBFS is detected, by default. So you don't really need to add that switch to eac3to.
Recommended to use stereo if you have plain stereo playback environment (tv,etc).
-downProLogic if you have a surround sound environment that can decode Dolby Pro Logic II.

At least with eac3to, you get a log that gives you useful information.
Regarding updates, FFMPEG and eac3to should be be equal in updates. Not a whole lot has happened with DTS regarding last updates.

[Bigmango]

Originally Posted by tebasuna51

The GUI is UsEac3to, and yes is a GUI limit, I can't understand for what we can need more than 640 Kb/s for lossy 5.1

For all the devices that can't play TrueHD or DTSMA. (i.ex. people streaming from their plex or emby server to their TVs. Even more so, look at the high end 10'000+$ Samsung TVs, they can't even play DTS, but they do play ac3 and eac3).

In the above example, streaming to the TV, with the audio out via HDMI-ARC to a receiver with the TrueHD/DTSMA re-ecoded to eac3 1664k (which is the highest bitrate for the eac3 bluray spec according to the Dolby Media Encoder) makes it as transparent as the lossless audio (depending on your ears you might need less, but better be safe, especially with audiophile headphones, etc... ).

That being said, the new E-ARC now passes TrueHD and DTSMA through, so the eac3 encoding will become less relevant in the near future.

[Bigmango]

Originally Posted by tebasuna51

In my opinion 7.1 don't offer a better 2D surround than 5.1, I think is a commercial placebo, then for me is ok the ffmpeg behaviour.

Using a 7.1 source, the 5.1 at 1536k eac3 produced by ffmpeg is poor compared to the 7.1 produced by the Dolby Media Encoder. (I have tested with both).

There is a big soundstage difference.

The difference is night and day with some good audiophile reference headphones with a big soundstage (take a Sennheiser HD 650 for example...).

[Bigmango]

Originally Posted by justnobody

ffmpeg will not support eac3 7.1 encode, just forget it and go

According to the ffmpeg tracker, the developper who implemented the 5.1 eac3 said that he will work on adding the 7.1, but that was a couple years ago and nothing has happened since...

[Bigmango]

Originally Posted by SeeMoreDigital

I also created a 6 channel EAC3 encode at 1536 Kbps using one of my DTS audio CD's as a source. And I have to say that the playback results are very good indeed.

FYI, these are the maximum bitrates eac3 can go up to with the Dolby Media Encoder:

DD+ for bluray: 1664k. (this works fine over HDMI-ARC).
DD+ standard: 3024k (I have not tested this over ARC, but according to the information I could find online, ARC supports ~1Mbs (EARC 38Mbs); so this would be the reason for the DD+ bluray spec.).

[SeeMoreDigital]

Originally Posted by Bigmango

Using a 7.1 source, the 5.1 at 1536k eac3 produced by ffmpeg is poor compared to the 7.1 produced by the Dolby Media Encoder. (I have tested with both).

There is a big soundstage difference.

The difference is night and day with some good audiophile reference headphones with a big soundstage (take a Sennheiser HD 650 for example...).

Can you upload both of your test sample encodes for us please?

Have you compared both encoders using the same 5.1 PCM source encoded at the same bit-rate?

[Sonic3R]

Hey, there’s a source code for eac3to? I wish, if possible, to adapt it for cross platform means to be used in Linux/Mac too...

[jpsdr]

As far as i know, the source code is not avaible, and it's in delphi.

[tebasuna51]

@Bigmango
I accept, but not share your opinions (headphones for 7.1, better than 5.1?).
Of course commercial encoders can be better than free ones.

BTW this is a eac3to thread than can't encode to eac3 byself.
The eac3 bitrate limitation is in the UsEac3to GUI than use ffmpeg to encode.
That GUI can be modified, I supply the autoit source code, and recompiled for free

You only need change the line 1895:
GUICtrlSetData($bit_2, "640|576|512|448|384|320|256|224|192|160|128|112|E640|E576|E512|E448|E384|E320|E256|E224|E192|E160|E128|E112|E96|E80|E64", "640")

And include the bitrates desired:
GUICtrlSetData($bit_2, "640|576|512|448|384|320|256|224|192|160|128|112|E6144|...|E768|E640|E576|E512|E448|E384|E320|E256|E224|E192|E160|E128|E112|E96|E80|E64", "640")

[tebasuna51]

Originally Posted by jpsdr

As far as i know, the source code is not avaible, and it's in delphi.

You are right, madshi never want public the source code.

[Bigmango]

Originally Posted by SeeMoreDigital

Can you upload both of your test sample encodes for us please?

I don't have the time now for some demuxing/cutting, but I'll see if I can get this for you a little later.

In the mean time, I will give you all the info I can below:

Originally Posted by SeeMoreDigital

Have you compared both encoders using the same 5.1 PCM source encoded at the same bit-rate?

Yes the difference is there, not only with 7.1, but also with 5.1 sources.

In comparison, the ffmpeg DD+ sounds more "flat" / bland.

The Dolby Media Encoder audio has more "presence". On some good reference headphones like the Sennheiser HD 650 which have an amazing soundstage, the surround is perfectly positioned and moves around in an amazing way.

With the Dolby Encoder audio, the movies just "move" more. Immersion is much better. The result is that the movies are better (I often feel like I am rediscovering my movies after replacing the 5.1 ffmpeg DD+ @ 1536k with the Dolby Encoder version @ 1664k).

The difference is not huge, but it is there. It's sometimes subtle (but even subtle when compared on a short clip, if you watch a movie for a longer time the experience/immersion is a lot better thanks to these improvements) and perhaps to understand the subtlety level I am talking about, you could compare it to something like the difference between a 384k ac3 and lossless (or DTS 1509). (But here I am not talking about audio quality, but "presence". More Flat vs more Alive).

I suspect this better/stronger presence of the surround effects to be caused by the way the Dolby Encoder is applying the metadata, and using an AV receiver that knows how to decode this metadata.

These are the settings the Dolby Media Encoder uses by default (which I use):

Encoder settings:

Dialog level: -31
Data rate : 1280k for 7.1 , 768k for 5.1 (I set it @ 1664k for both)
Bitstream mode: "Complete main" (Other options are: "Music & Effects", "Visually Impaired", "Hearing Impaired", "Dialog", "Commentary", "Emergency", "Voice over").

Preprocessing:

Line mode profile: Film standard (Other options are : "Film light", "Music standard", Music light", "Speech", "None").
RF mode profile: Film Standard (Other options: all the same as Line mode profile)

Channel bandwidth low pass filter: ON
LFE low pass filter: ON
DC high pass filter: ON
Surround channel 90-Degree phase shift: ON
Surround channel 3db attenuation: OFF

(All of these settings and what they do is explained in the Dolby Media Encoder PDFs, which you can easily find with a google search).

As you can see, my guess is that these settings (which are the defaults) is where the magic is happening.

[Bigmango]

Originally Posted by Sonic3R

Hey, there’s a source code for eac3to? I wish, if possible, to adapt it for cross platform means to be used in Linux/Mac too...

It works perfectly on Linux with wine (I use "wine UsEac3to.exe" all the time, works perfect).

But yes, a native port would be great.

[kdantas]

Originally Posted by Bigmango

It works perfectly on Linux with wine (I use "wine UsEac3to.exe" all the time, works perfect).

But yes, a native port would be great.

Hi @Bigmango, nice to know. Can you indicate a tutorial explaining, if possible, how to install and run eac3to with UsEac3to on Ubuntu Server 16.04 Xenian Xerus? I would like to remux my BluRays from my dedicated server. I also know that I will need to run mkvtoolnix to join the demuxed files. Any information is welcome. And sorry if this is a noob question, but my knowledge of linux is almost zero.

[cypher007]

trying to convert a THD stream. ive demuxed the mkv using eac3to then tried to extract the wavs but it complains about Lossless check failed and eventually errors with:

The libav decoder reported error -1094995529 while decoding. <ERROR>
Aborted at file position 1268252672. <ERROR>

[tebasuna51]

Try decode to w64 with ffmpeg, if it also abort maybe you have a corrupt track.

[cypher007]

Originally Posted by tebasuna51

Try decode to w64 with ffmpeg, if it also abort maybe you have a corrupt track.

same error. but if i use ripbot264 it will create a W64.

i did wonder if i could use this to then extract wavs from. when i tried it worked but when i checked the wavs they were 16bit not 24bit as i expected.

[tebasuna51]

For what do you expect 24 bits, what is the source?

[cypher007]

its a truehd stream so assumed 24bit. though my knowledge of bit depth in truehd is limited.

why is it ripbot can demux the truehd to w64? and not eac3to.