Looking for a eac3 7.1 encoder

[nevcairiel]

If a player cannot handle EAC3, it wont be able to play a pure EAC3 stream. That lossless conversion to AC3 is just theoretical marketing fluff. EAC3 supports higher bitrates then AC3, how could you make that a lossless conversion.
Or they simply refer to the Blu-ray profile, pushing all the features in marketing at the same time, eventhough you can't actually combine everything.

[SeeMoreDigital]

Originally Posted by NiN3

nevcairiel said the EAC3 track does not include a AC3 core inside it unless you use the Blu-ray Disc profile, in which case it's mandatory.

This is true...

An AC3 core is mandatory for the Blu-ray specification. But back in the day, it wasn't mandatory for the DVD HD specification.

Dolby had to fiddle about with EAC3 again when DVB-T2, DVB-S2 and DVB-C2 decoder support was added to European TV's...

[NiN3]

Originally Posted by nevcairiel

If a player cannot handle EAC3, it wont be able to play a pure EAC3 stream. That lossless conversion to AC3 is just theoretical marketing fluff. EAC3 supports higher bitrates then AC3, how could you make that a lossless conversion.
Or they simply refer to the Blu-ray profile, pushing all the features in marketing at the same time, eventhough you can't actually combine everything.

I didn't literally mean a lossless conversion but more like if you have a 640k AC3 track and a 1024k EAC3 track that gets converted down to AC3 because your receiver doesn't support EAC3, would those both end results sound identical or would the native AC3 track sound slightly better because the other one had to be converted from a "lossy" source. If that makes any sense.

This is what it says on wikipedia: "Dolby Digital Plus bitstreams are not directly backward compatible with legacy Dolby Digital decoders. However, Dolby Digital Plus is a functional superset of Dolby Digital, and decoders include a mandatory component that directly converts (without decoding and re-encoding) the Dolby Digital Plus bitstream to a Dolby Digital bitstream (operating at 640 kbit/s) for carriage via legacy S/PDIF connections (including S/PDIF over HDMI) to external decoders (e.g. AVRs, etc.). All Dolby Digital Plus decoders can decode Dolby Digital bitstreams."

This paper actually has a very interesting explanation for the EAC3 to AC3 transcoding process starting from page 22: https://professional.dolby.com/globa...gital-plus.pdf

[NiN3]

Originally Posted by SeeMoreDigital

This is true...

An AC3 core is mandatory for the Blu-ray specification. But back in the day, it wasn't mandatory for the DVD HD specification.

Dolby had to fiddle about with EAC3 again when DVB-T2, DVB-S2 and DVB-C2 decoder support was added to European TV's...

Any idea when this new standard came to be?

[SeeMoreDigital]

Originally Posted by NiN3

Any idea when this new standard came to be?

Like all standards, the Dolby Digital (AC-3 and E-AC-3) standard has been revised over the years.

The (25 January) 2018 ATSC standards can be downloaded here: https://www.atsc.org/wp-content/uplo...A52-2018-1.pdf. Which includes a revisions page...

[NiN3]

Originally Posted by nevcairiel

If a player cannot handle EAC3, it wont be able to play a pure EAC3 stream. That lossless conversion to AC3 is just theoretical marketing fluff. EAC3 supports higher bitrates then AC3, how could you make that a lossless conversion.
Or they simply refer to the Blu-ray profile, pushing all the features in marketing at the same time, eventhough you can't actually combine everything.

I don't want to bother you with too many questions but you seem very knowledgeable and it's always nice to learn from experts.

What's your opinion on efficiency between AC3, EAC3 and DTS if encoded at 640, 1024, and 1509 respectively. Is there any point in having EAC3 at all or is the improvement compared to AC3 minimal at best. Common consensus seems to be that AC3 and DTS are usually transparent to each other even with the large difference in file size, would EAC3 at 1024 compete better against DTS at 1509?

[tebasuna51]

A old multichannel test show EAC3 (DD+) 448 Kb/s near DTS 1500 Kb/s.

[filler56789]

Originally Posted by tebasuna51

A old multichannel test show EAC3 (DD+) 448 Kb/s near DTS 1500 Kb/s.

Sadly it seems nobody cared about doing new comparison tests after the release of the Master Audio Suite My educated guess says 1509 kbps has always been overkill for six-channel (5.1) lossy DTS and 1344 kbps (or even 1280 kbps) would be sufficient for being qualified as «perceptually-lossless», but it would be nice to have an "official confirmation" so to speak.

[tebasuna51]

Yes, a new test can be nice. Maybe EAC3, AAC can be better than in 2007, and include also Opus.

But seems than EAC3, AAC and Opus have the same quality than old DTS with 1/3 of bitrate more or less.

[SeeMoreDigital]

Originally Posted by tebasuna51

A old multichannel test show EAC3 (DD+) 448 Kb/s near DTS 1500 Kb/s.

I'm inclined to agree that multi-channel DTS was 'over bit-rated' at 1509.75 kbps or 1536kbps. Indeed, it sounds perfectly fine when encoded at 754.875kbps or 768kbps... Which is pretty good for an audio format that was developed in the early 1990's

[NiN3]

I hate to beat a dead horse but I do find it an interesting subject so I did some extra reading of that Dolby paper I posted a few comments above in hopes of trying to learn a bit more about EAC3 in general.

It seems that regardless of the bitrate of the EAC3 stream, your TV's built-in "EAC3->AC3 converter" converts it to AC3 640kbps by default which seems kinda smart since TV broadcasters can now send an EAC3 stream at a much lower bitrate than 640 to save bandwidth and then lets your TV do the conversion to AC3 and since EAC3 is much more efficient at low bitrates technically the conversion will be almost "lossless" as the low bitrate EAC3 gets converted to a high bitrate AC3. (high relative to the even lower EAC3 bitrate obviously, not like 640 is considered high).

And for bitrates higher than 640kbps it'll just throw away the extra information and it ends up being a waste of bandwidth.

This is what I've been wondering, how much loss is there exactly during that conversion? According to the paper it's not a conventional transcode (EAC3 decode -> PCM -> AC3 encode), but majority of the code stays untouched since both codecs were originally built on the same principles, so there shouldn't be much loss in there compared to just doing a lossy to lossy transcode using ffmpeg/eac3to. If one were to encode an AC3 and EAC3 from the same source and play on a TV with S/PDIF connection, the EAC3 would get converted to AC3 while the main AC3 would stay untouched, would both of these end products sound identical? Or would the untouched AC3 sound slightly better than the downconverted one as a result of the "transcoding" process? Would it be worth future-proofing by encoding everything in EAC3 5.1 instead of AC3 5.1?

Anyway, sorry for my long ass questions. There aren't many places to learn this stuff.

[SeeMoreDigital]

Originally Posted by NiN3

It seems that regardless of the bitrate of the EAC3 stream, your TV's built-in "EAC3->AC3 converter" converts it to AC3 640kbps by default which seems kinda smart

Eh?

My LG TV does not convert EAC3 to AC3... It's able to decode native EAC3 up-to 5.1 channels just fine. It's also able to pass EAC3 as a bit-stream via HDMI ARC just fine too!

An SPDIF transport is too old to support EAC3. Hence it's conversion to AC3...

[NiN3]

Originally Posted by SeeMoreDigital

Eh?

My LG TV does not convert EAC3 to AC3... It's able to decode native EAC3 up-to 5.1 channels just fine. It's also able to pass EAC3 as a bit-stream via HDMI ARC just fine too!

You can't pass EAC3 using S/PDIF so TV's convert it to AC3 640k. That's the whole point and why I mentioned the document..

[nevcairiel]

Originally Posted by NiN3

You can't pass EAC3 using S/PDIF so TV's convert it to AC3 640k. That's the whole point and why I mentioned the document..

But thats why someone invented HDMI and (e)ARC.

[NiN3]

Originally Posted by nevcairiel

But thats why someone invented HDMI and (e)ARC.

Right, but I am specifically talking about the backwards compatibility of EAC3, as mentioned in the document... That's what I was asking.

[SeeMoreDigital]

Originally Posted by NiN3

Right, but I am specifically talking about the backwards compatibility of EAC3, as mentioned in the document... That's what I was asking.

Hmmm...

Given that HDMI is currently the de-facto transport system for both video and audio, it's a bit of a pointless discussion....

[NiN3]

Originally Posted by SeeMoreDigital

Hmmm...

Given that HDMI is currently the de-facto transport system for both video and audio, it's a bit of a pointless discussion....

Which is why I wasn't talking about HDMI but about the backwards compatibility of EAC3 with legacy AC3 devices that dominate the average living room.

[SeeMoreDigital]

I think it's time to put this topic, back on topic!

[Ripmann]

Originally Posted by SeeMoreDigital

I think it's time to put this topic, back on topic!

Putting it back on topic, I'm kind of stumped that there seem to be no available 7.1 E-AC3 solutions in 2021, especially considering that uncompressed TrueHD 7.1 streams for movies routinely take is 3-4GB in [mostly wasted] space.

Were there any developments in 7.1 E-AC3 encoding since 2020? I just started looking for it (finally got a cheap 7.1 speaker set) and was genuinely surprised to learn that neither eac3to nor ffmpeg support this rather essential feature. Anyone?

[tebasuna51]

I want a Atmos surround 3D (at least 5.2.1) EAC3 encoder better than a 2D 7.1