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I notice that most DD audio bitrates are 384kBps, but I notice FOX (uplinked by directv) and all turner networks, such as CNN TNT and TBS are 448 kbps If directv is using the same encoders, why would they differ? and why wouldn't they use the higher 448 for everything?
 

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ejjames said:
I notice that most DD audio bitrates are 384kBps, but I notice FOX (uplinked by directv) and all turner networks, such as CNN TNT and TBS are 448 kbps If directv is using the same encoders, why would they differ? and why wouldn't they use the higher 448 for everything?
Interesting question. How can you tell what the bit rates are? I have an HR20 and I don't see any bite rate display. I have read recently in the dolby.com web site that Dolby Digital Plus is a possible on satellite broadcasts. I have limited understanding of all the details, but I understand DD+ will allow up to 7.1 channels and will require a higher bit rate.

Since DD+ is backward compatible with legacy 5.1 systems, what would stop DirecTV from implementing this enhancement? Does Dolby Digital Plus require HDMI 1.3 for the 7.1 version, or will it run on lesser versions of HDMI? This would be a very nice accompaniment to the forthcoming 1080p upgrade.

Who knows the answers?
 

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HDMI 1.3 is not required for DD+, 1.1 is. If you have an HDMI receiver capable of decoding DD+, if it's ever implemented, you should be good to go. If the bit rates are less than the DD 5.1 standard, that's done by the provider, D* just passes the audio as received. I doubt we'll see DD+ as that would take new audio equipment on the provider's end. Yes, it's backward compatable with 5.1, in other words, if you don't have the + decoder, you just get the core 5.1 DD, but the additinal 2 channels have to be encoded in the signal and a 5.1 encode/transmitter will not handle the 7.1 signal.
 

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The Scotsman said:
Interesting question. How can you tell what the bit rates are? I have an HR20 and I don't see any bite rate display. I have read recently in the dolby.com web site that Dolby Digital Plus is a possible on satellite broadcasts. I have limited understanding of all the details, but I understand DD+ will allow up to 7.1 channels and will require a higher bit rate.

Since DD+ is backward compatible with legacy 5.1 systems, what would stop DirecTV from implementing this enhancement? Does Dolby Digital Plus require HDMI 1.3 for the 7.1 version, or will it run on lesser versions of HDMI? This would be a very nice accompaniment to the forthcoming 1080p upgrade.

Who knows the answers?
DD only goes to 5.1. DD-EX goes to 6.1 (a poor version of 6.1). There's no DD that does 7.1. DD+ is just high bitrate DD and thus is 5.1 (DD+-EX would go to 6.1).

No DD of any sort requires HDMI. Dolby TrueHD (which is lossless) requires HDMI, as do the various DTS HD formats (most notably DTS-HD MA which is also lossless).

You won't see lossless audio on DirecTV any time soon. TrueHD and DTS-HD MA run between 3 and 6 mbits/sec, which is about the same amount of bandwidth as D* allocates to their video signals.

I didn't know Dolby Digital plus was an official name, I thought it was just made up by the internet. In my understanding people usually use it to refer to Dolby Digital at 640kbps (the max allowed by the spec).
 

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No, DD+ does provide 7.1 channels, in fact up to 8 total in a single encoded stream, and DD+ is up to 3 Mbs/sec.
 

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Discussion Starter · #8 ·
The Scotsman said:
Interesting question. How can you tell what the bit rates are? I have an HR20 and I don't see any bite rate display. I have read recently in the dolby.com web site that Dolby Digital Plus is a possible on satellite broadcasts. I have limited understanding of all the details, but I understand DD+ will allow up to 7.1 channels and will require a higher bit rate.

Since DD+ is backward compatible with legacy 5.1 systems, what would stop DirecTV from implementing this enhancement? Does Dolby Digital Plus require HDMI 1.3 for the 7.1 version, or will it run on lesser versions of HDMI? This would be a very nice accompaniment to the forthcoming 1080p upgrade.

Who knows the answers?
My yamaha receiver shows me bitrates and number of channels present.
 

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ejjames said:
My yamaha receiver shows me bitrates and number of channels present.
And DarinC's link provides the answers for future broadcasts. I was unaware it was adopted for future ATSC and DBS, Cool.
 

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DarinC said:
This is new to me. That's a different Dolby Digital Plus than what the internet had termed DD+. Which is not unusual, Dolby is not required to follow the lead of the internet when naming new stuff. But just know that if you do searching on the internet or see DD+ in a forum, it's at least as likely to refer to 640kbps DD as it is this new TrueHD-family Dolby Digital codec. But yes, when you read my post above, know that what I was referring to is not what Dolby refers to as Dolby Digital Plus. I'll try to find new terminology to use in the future that is more compatible with Dolby's naming scheme.

This new codec (the one Dolby calls Dolby Digital Plus) will require HDMI cabling and special processing inside the unit to get any new capabilities, so I don't expect to see it soon on D* for those reasons. For example, the Xbox 360 supports HDMI audio out, but it only can output the same thing on HDMI that it does on optical out, which means it cannot do any audio format that cannot be put over optical. The current D* receivers are almost certainly the same way.

Additionally, as I said, D* is unlikely to allocate a video-channel's worth of bandwidth to audio for a movie.
 

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flipptyfloppity said:
That's a different Dolby Digital Plus than what the internet had termed DD+. ... But just know that if you do searching on the internet or see DD+ in a forum, it's at least as likely to refer to 640kbps DD as it is this new TrueHD-family Dolby Digital codec.
I think you're thinking of the same thing, but just not realizing it. It's the same DD+ that's been around since the beginning of HD DVD. You will see many people say that DD+ is the same thing as DD, but with higher bitrates. And that's generally true. DD+ supports higher bitrates and channel numbers than legacy DD. But if a movie is encoded in DD+, and it's only 5.1 channels, then it essentially is the same thing as DD. But assuming it's on a high bandwidth media, it likely has higher bitrate than legacy DD would have had on SD DVD.
 

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flipptyfloppity said:
Additionally, as I said, D* is unlikely to allocate a video-channel's worth of bandwidth to audio for a movie.
DD+ @ 1.5 Mbps (thats megabits, not megabytes) in 7.1 is a single stream codec and could be sent and passed by the D* DVRs, the decoding would be done by an AVR. A TV would just "see" the DD 5.1 core that is used now so the compatibility would be there as it is now. Optical or coaxial out to older DD only AVRs would still function as they do now. The additional bandwidth is negligible so we may see this in the not too distant future with the movie channels.
 

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HD AV said:
DD+ @ 1.5 Mbps (thats megabits, not megabytes) in 7.1 is a single stream codec and could be sent and passed by the D* DVRs, the decoding would be done by an AVR. A TV would just "see" the DD 5.1 core that is used now so the compatibility would be there as it is now. Optical or coaxial out to older DD only AVRs would still function as they do now. The additional bandwidth is negligible so we may see this in the not too distant future with the movie channels.
The additional bandwidth is far from negligible. It would represent an increase of 12% or more in stream size. Let's say hypothetically there were a 1h37m 1080 movie that was about 6GBytes in size right now. That's 8.8mbit/sec, of which about 400kbit/sec is audio right now. Add in another 1.2mbit/sec of audio, and it grows to 10mbit/sec, an increase of 12.5%.

That would require D* remove 1 in 9 of their HD PPV movies in order to make space for fancier audio. And how do they advertise that? Remember D* went from 100 channels at premium quality to 1000 channels mashed all to hell over time. Quantity sells over quality.

Also, how can DD+ be single stream if it is backward compatible with old DD? It seems to me it has to have a core stream and an enhancements stream.
 

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flipptyfloppity said:
Also, how can DD+ be single stream if it is backward compatible with old DD? It seems to me it has to have a core stream and an enhancements stream.
Evidently, you didn't read the entire link posted above as umm.

Features
Multichannel sound with discrete channel output.
Channel and program extensions can carry multichannel audio programs of up to 7.1 channels* and support multiple programs in a single encoded bitstream.
Outputs a Dolby Digital bitstream for playback on existing Dolby Digital systems.
Supports data rates as high as 6 Mbps.
Bit rate performance of at least 3 Mbps on HD DVD and up to 1.7 Mbps on Blu-ray Disc.
Accurately reproduces what the director and producer intended.
Interactive mixing and streaming capability in advanced systems.
Supported by HDMI™, the new single-cable digital connection for high-definition audio and video.
Benefits

Can deliver 7.1 channels and beyond* of enhanced-quality audio at up to 6 Mbps.
Allows multiple languages to be carried in a single bitstream.
Offers audio professionals new creative power and freedom.
Compatible with the millions of home entertainment systems equipped with Dolby Digital.
No latency or loss of quality in the conversion process.
Maintains high quality at more efficient broadcast bit rates (200 kbps for 5.1-channel audio).
Selected by the Advanced Television Systems Committee (ATSC) as the standard for future broadcast applications; named as an option by the Digital Video Broadcasting (DVB) Project for satellite and cable TV.
Selected as the mandatory audio format for HD DVD and as an optional audio format for the Blu-ray Disc.
 

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HD AV said:
Evidently, you didn't read the entire link posted above as umm.

Features
Multichannel sound with discrete channel output.
Channel and program extensions can carry multichannel audio programs of up to 7.1 channels* and support multiple programs in a single encoded bitstream.
Outputs a Dolby Digital bitstream for playback on existing Dolby Digital systems.
Supports data rates as high as 6 Mbps.
Bit rate performance of at least 3 Mbps on HD DVD and up to 1.7 Mbps on Blu-ray Disc.
Accurately reproduces what the director and producer intended.
Interactive mixing and streaming capability in advanced systems.
Supported by HDMI™, the new single-cable digital connection for high-definition audio and video.
Benefits

Can deliver 7.1 channels and beyond* of enhanced-quality audio at up to 6 Mbps.
Allows multiple languages to be carried in a single bitstream.
Offers audio professionals new creative power and freedom.
Compatible with the millions of home entertainment systems equipped with Dolby Digital.
No latency or loss of quality in the conversion process.
Maintains high quality at more efficient broadcast bit rates (200 kbps for 5.1-channel audio).
Selected by the Advanced Television Systems Committee (ATSC) as the standard for future broadcast applications; named as an option by the Digital Video Broadcasting (DVB) Project for satellite and cable TV.
Selected as the mandatory audio format for HD DVD and as an optional audio format for the Blu-ray Disc.
No, the real reason I asked the question is because I have a strong tendency to ignore marketing text and instead ask questions when there are answers I can't explain.

Like, for example, how can ther be "no latency or loss of quality in the conversion process"? You can't even apply a simply low pass filter without adding latency. Let alone clump up data into packets for filtering and compression.
 

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ejjames said:
My yamaha receiver shows me bitrates and number of channels present.
So far I've learned from this thread that DD+ needs to run on HDMI version 1.1 or better, and I presume that means existing D* receivers would not need a hardware upgrade. Reading the posts from HD AV and Darin C, it seems the increase in required bit rate would indeed be relatively small. Also, existing 5.1 sound systems would still function, because DD+ is backward compatible.

Is there an engineer from DirecTV reading this thread? If it is physically possible to implement DD+ (with 7.1 channels) and nobody would be at a disadvantage, do we have a significant audio enhancement to look forward to?

To ejjames, I have a Yamaha RX-V863 receiver. Please tell me how you display the audio bit rate on your Yamaha.

Cheers
Archie
 

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flipptyfloppity said:
No, the real reason I asked the question is because I have a strong tendency to ignore marketing text and instead ask questions when there are answers I can't explain.

Like, for example, how can there be "no latency or loss of quality in the conversion process"? You can't even apply a simply low pass filter without adding latency. Let alone clump up data into packets for filtering and compression.
I guess the best analogy is DD+ is to DD what MPEG4 is to MPEG2, an improvement in compression algorithms and techniques. I do know DD+ from HD DVD and BR sounds better on my DD decoder due to the higher bit rate of the "core" DD my decoder extracts and the separation is (perceived) better also. I believe the statement concerning latency or loss of quality in the conversion process is speaking to decoding. There are such things as "lossless encoding"/compression codecs now. MrSID for tiff files is a prime example.
 

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The Scotsman said:
So far I've learned from this thread that DD+ needs to run on HDMI version 1.1 or better...
I could be wrong, do not believe that is correct. You should be able to transfer DD+ via toslink or coaxial. Since it's still a lossy scheme that at it's core is the same as DD, you don't have the security and bandwidth issues you have with the lossless formats.
 

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You can transfer DD+ via optical or coaxial, you only get the core DD, but you do get a higher bit rate. To get + you must use HDMI, or 7.1 analogue in, and have an AVR capable of decoding DD+.
 

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HD AV said:
You can transfer DD+ via optical or coaxial, you only get the core DD, but you do get a higher bit rate. To get + you must use HDMI, or 7.1 analogue in, and have an AVR capable of decoding DD+.
If you were using 7.1 analogue in, then presumably the DD+ has already been decoded by the source. Why would the AVR need to be capable of decoding anything?
 
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