[wesk05]

When discussing types - are you referring to this ?
What does this mean for a 5.1 E-AC3 Type 0 stream - which presumably is NOT AC3 encoded data?

Yes, I was referring to the stream types that you have listed. Type 0 is also "re-wrapped", just more changes in the audio block of the syncframe.

Double Tongue tied, with a twist of Lemon if ever I saw a sentence
Ha Ha !
Do you mean to say "it is correct to state that there is no decoding/encoding involved in the conversion of Dolby Digital Plus bit stream to Dolby Digital....." ?

Yes, that's what I meant. Wasn't it obvious?

[Jdiesel]

If Nvidia decided to not include Dolby licensing for overall cost reduction on the Shield it would be nice if they offer the option to pay for a license key similar to what can be done on the RPi for MPEG-2 and VC-1.

[noggin]

When discussing types - are you referring to this ?
What does this mean for a 5.1 E-AC3 Type 0 stream - which presumably is NOT AC3 encoded data?

Yes, I was referring to the stream types that you have listed. Type 0 is also "re-wrapped", just more changes in the audio block of the syncframe.

Double Tongue tied, with a twist of Lemon if ever I saw a sentence
Ha Ha !
Do you mean to say "it is correct to state that there is no decoding/encoding involved in the conversion of Dolby Digital Plus bit stream to Dolby Digital....." ?

Yes, that's what I meant. Wasn't it obvious?

So is 5.1 E-AC3 the same in compression terms as 5.1 AC3 (i.e. they haven't introduced a new, more efficient scheme) just wrapped differently, with the main differences being the addition of a supplementary stream to allow 7.1 (and I guess Atmos) audio to be carried as an additional stream? (And because the rear channels for a 5.1 mix downmixed from 7.1 and a native 7.1 stream are different you have to carry 2 surrounds for 5.1 and 4 different surrounds for 7.1 - meaning there is an overhead compared to carrying 7.1 only and letting the receiver downmix - because E-AC3 has to be backwards compatible in the compressed audio domain and thus has to be 5.1 in the primary stream?)

If both Type 0 and Type 2 streams can be re-wrapped from E-AC3 to AC3 with no transcoding that suggests the core compression scheme is the same?

[noggin]

If Nvidia decided to not include Dolby licensing for overall cost reduction on the Shield it would be nice if they offer the option to pay for a license key similar to what can be done on the RPi for MPEG-2 and VC-1.

I think the market for that is so niche, nVidia wouldn't want the hassle of managing it. The Pi Foundation are in a different situation, but it did take a while for them to start the licensing scheme.

[Soli]

It cannot just be wrapped differently. I don't know all details but Dolby themselves call it hybrid recompression which suggeste same parts are transcoded while the common parts are carried over. Maybe AC3filter is able to do this too, which then the answer would lie in the source code.

I guess the reason there is an overhead in 7.1 channels or more is to simplify the conversion from dd+ to ac3.
Downmixing 7.1 to 5.1 would surely involve both downmixing and reencoding right?

[wesk05]

So is 5.1 E-AC3 the same in compression terms as 5.1 AC3 (i.e. they haven't introduced a new, more efficient scheme) If both Type 0 and Type 2 streams can be re-wrapped from E-AC3 to AC3 with no transcoding that suggests the core compression scheme is the same?

You are a tenacious person I thought I could get away with the one sentence reply. I didn’t want to get into the details, that’s why I said “re-wrapped” and “changes in the audio block”. There is actually more to it. @Soli is correct in saying that Dolby may be stretching the truth when the say there is no decoding/reencoding in the conversion process. That is true if none of the enhancements of E-AC-3 is used (these enhancements are what contribute to the greater compression efficiency of E-AC-3). In such cases you can just "re-wrap" the bit stream. If E-AC-3 features like vector quantization (VQ), gain adaptive quantization (GAQ), channel coupling/phase preservation, spectral extension etc. are used in the bit stream, there is indeed a partial decode/encode for requantization during the conversion process. Unlike the open source encoders/decoders, there is NO decoding to PCM during the conversion. The partial decode/encode remains in the frequency domain. Encoding parameter data such as snroffset used for bit allocation, exponent/coupling exponent strategy, audio blocks in the frame used for calculations etc. are already carried in the E-AC-3 bit stream. The converter can utilize those data for converting the E-AC-3 bit stream to AC-3. In short, the conversion process is less computational than a full decode/encode.

Hope you are satisfied with the answer I may not be able to give more details.

[noggin]

So is 5.1 E-AC3 the same in compression terms as 5.1 AC3 (i.e. they haven't introduced a new, more efficient scheme) If both Type 0 and Type 2 streams can be re-wrapped from E-AC3 to AC3 with no transcoding that suggests the core compression scheme is the same?

You are a tenacious person

I like to try and understand things properly :-)

I thought I could get away with the one sentence reply. I didn’t want to get into the details, that’s why I said “re-wrapped” and “changes in the audio block”. There is actually more to it. @Soli is correct in saying that Dolby may be stretching the truth when the say there is no decoding/reencoding in the conversion process. That is true if none of the enhancements of E-AC-3 is used (these enhancements are what contribute to the greater compression efficiency of E-AC-3). In such cases you can just "re-wrap" the bit stream. If E-AC-3 features like vector quantization (VQ), gain adaptive quantization (GAQ), channel coupling/phase preservation, spectral extension etc. are used in the bit stream, there is indeed a partial decode/encode for requantization during the conversion process. Unlike the open source encoders/decoders, there is NO decoding to PCM during the conversion. The partial decode/encode remains in the frequency domain. Encoding parameter data such as snroffset used for bit allocation, exponent/coupling exponent strategy, audio blocks in the frame used for calculations etc. are already carried in the E-AC-3 bit stream. The converter can utilize those data for converting the E-AC-3 bit stream to AC-3. In short, the conversion process is less computational than a full decode/encode.

Hope you are satisfied with the answer I may not be able to give more details.

Yep - next question... How does Dolby E relate to AC3 (I get deafened by it often enough...)

[saipanda]

Disclaimer: I'm an audio newbie.

I've read through this thread and researched elsewhere but I'm a bit stumped. Will I be able to get 5.1 via netflix/amazon with a Shield connected to a Samsung KS800 via HDMI with an optical link from the TV to a Sonos 5.1 setup? I don't have a separate receiver.

[Jdiesel]

Disclaimer: I'm an audio newbie.

I've read through this thread and researched elsewhere but I'm a bit stumped. Will I be able to get 5.1 via netflix/amazon with a Shield connected to a Samsung KS800 via HDMI with an optical link from the TV to a Sonos 5.1 setup? I don't have a separate receiver.

No you will not get 5.1 audio from Neflix or Amazon with that setup, only 2 channel audio. You will be able to get 5.1 audio bitstreamed as AC3/DTS in Kodi however. This is due to the fact that the EAC3 audio used by Netflix/Amazon can only be passed through an HDMI connection not optical or be converted to AC3 which Nvidia did not include the license to do.

[wrxtasy]

Actually I disagree with what Jdiesel has just written....

@saipanda,
It depends if your Samsung TV is Licenced for Dolby Digital Plus Audio(DD+) and can accept DD+ input (via Passthrough) over HDMI from the Shield.

I've just looked at the Tech Specs for this TV and yes it supports Dolby Digital Plus Audio.

Audio
Dolby
Dolby Digital Plus

Your TV is DD+ Licensed and should be able to convert/decode 7.1 DD+ into 5.1 DD to send that out over Optical to the Sonos.
It looks like it supports 5.1 DTS Audio as well, which is pretty unusual.

Nothing is 100% certain unless someone is already using this setup and can confirm, but you have all the necessary Dolby Licence requirements in that TV to accept DD+ Audio from the Netflix, Amazon and VUDU Apps.

In THIS post @rde135, is getting DD Audio from Netflix on the Shield when used with a 4K Samsung TV.

[noggin]

Actually I disagree with what Jdiesel has just written....

@saipanda,
It depends if your Samsung TV is Licenced for Dolby Digital Plus Audio(DD+) and can accept DD+ input (via Passthrough) over HDMI from the Shield.

I've just looked at the Tech Specs for this TV and yes it supports Dolby Digital Plus Audio.

Audio
Dolby
Dolby Digital Plus

Your TV is DD+ Licensed and should be able to convert/decode 7.1 DD+ into 5.1 DD to send that out over Optical to the Sonos.

Though there is a possibility that this is limited to DD+ over HDMI ARC (Audio Return Channel) rather than Toslink. These days TV's support DD+ for Smart TV streaming apps for Netflix/Amazon etc. and the primary aim is to output this via HDMI ARC back to a connected amp. (ARC supports PCM2.0/DD/DD+ and DTS - though doesn't mandate DD+ or DTS support AIUI)

As you say, some may also support transcode/rewrap to DD for Toslink output.

It looks like it supports 5.1 DTS Audio as well, which is pretty unusual.

Getting less unusual for sets with ARC, though in this case it is more to support DVD players connected to a TV with audio output via ARC (rather than directly to the AVR). When I connect Kodi devices to my Sony UHD TV directly via HDMI, I get DD and DTS audio over ARC. (My AVR is not UHD - I have to connect a UHD source directly to my TV, and live with DD/DTS/PCM2.0 audio only. Will be upgrading to a new AVR when we go for a UHD Blu-ray player)

Nothing is 100% certain unless someone is already using this setup and can confirm, but you have all the necessary Dolby Licence requirements in that TV to accept DD+ Audio from the Netflix, Amazon and VUDU Apps.

In THIS post @rde135, is getting DD Audio from Netflix on the Shield when used with a 4K Samsung TV.

Yep - though as I said above - this may be more relevant for ARC than Toslink these days. It's entirely possible the Toslink output will be PCM2.0 for anything but audio received by the internal tuner. HOWEVER in the UK because our OTA system is based on AAC 5.1, most TVs sold here have DD encoders built in (to output 5.1 Dolby over Toslink from a 5.1 AAC broadcast) - so I suspect the presence of a DD encoder is a good sign. (And I expect all European sets will follow)

[wesk05]

How does Dolby E relate to AC3 (I get deafened by it often enough...)

I am pretty sure that you know that Dolby E audio has to be decoded to PCM before it can be encoded to Dolby Digital for delivery. The one thing that I can think of that may contribute to loudness is the dialnorm setting. It could be a mismatch with the actual LKFS/LUFS. Can't say for sure.

You may have seen this BBC white paper: Managing a real world Dolby E broadcast workflow

[noggin]

How does Dolby E relate to AC3 (I get deafened by it often enough...)

I am pretty sure that you know that Dolby E audio has to be decoded to PCM before it can be encoded to Dolby Digital for delivery. The one thing that I can think of that may contribute to loudness is the dialnorm setting. It could be a mismatch with the actual LKFS/LUFS. Can't say for sure.

You missed my point. (It wasn't THAT funny)

Dolby E is packaged as a PCM stereo-a-like signal (and routed either as AES/EBU or embedded) - and if you encounter it without a decoder in circuit you get a very LOUD (and unpleasant) digital noise. (On track level meters on the front of VTRs it just sits at a fixed, very loud, level)

[wrxtasy]

For Reference Info to this thread the Dolby Audio Licensed - Amazon FireTV2 can transcode DRM protected DD+ to DD with it's Android L Dolby support, details here:

(Amazon) - Dolby Integration Guidelines

[Bilalzaidi]

Every DVD worldwide and all HD broadcasts in the United States use Dolby Digital® (also known as AC-3). Dolby Digital 5.1 has evolved into Dolby Digital Plus, delivering up to 7.1 channels of surround sound in devices ranging from TVs to mobile phones.