Talk:Dolby Digital Plus

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Contents 1 DD+ 2 Downmixing? 3 13.1 channels? 4 Transcoding to AC-3 not required 5 HDMI EDID Short Audio Descriptor Byte 3 6 History?

[edit] DD+

Should DD+ be used as an abbreviation throughout the article? I am not sure its any sort of offical abbreviation from Dolby.

[edit] Downmixing?

This isn't the correct term to use. It's called transcoding. —The preceding unsigned comment was added by 139.222.232.75 (talk) 00:17, 5 March 2007 (UTC).

Downmixing refers to reducing the number of channels or reducing the sampling bits. For example from 24 bits per sample to 16 bits.

Transcoding refers to changing the compression algorithm from one format to another or changing the compression parameters. Don't know about the article where this occurs. Daniel.Cardenas 18:37, 10 July 2007 (UTC)

Actually converting from 24 bits to 16 bits would be downsampling, not downmixing.90.149.15.238 04:00, 21 October 2007 (UTC)

[edit] 13.1 channels?

'13.1 channels' does not make much sense to the layperson (what does the '.1' part refer to?). To improve the article, explain this from the start or link to a section of another page that offers an explanation.--ChrisJMoor 02:44, 17 March 2007 (UTC)

I've attempted to address your concern. Let me know if it doesn't. Unfortunately this is a subject area, where it's easy to slip into Jargonbot mode. Megapixie 09:13, 17 March 2007 (UTC)

[edit] Transcoding to AC-3 not required

As demonstrated by many Toshiba HD DVD players, transcoding to DTS is sufficient. --Ray andrew 16:11, 6 October 2007 (UTC)

[edit] HDMI EDID Short Audio Descriptor Byte 3

The HDMI 1.3a Specification, and the corresponding CEA-861D Specification indicate that the EDID value in a Short Audio Descriptor for DD+ support shall be decimal 10 in Byte #2. However there is no specified value for Byte #3. The CEA-861D indicates that the value for Byte #3 is zero, or specified by the Audio Codec Owner. I have searched on the Dolby web page, but cannot find this answer. Can someone help?Calbookaddict 21:19, 12 November 2007 (UTC) In an e-mail from Dolby Laboratories on 13 November 2007, I received the answer: There is no non-zero value defined for Byte 3 of the Short Audio Descriptor for Dolby Digital Plus – it should be set to zero. Byte 1 is used to indicate the Audio Format (set to decimal value 10 for Dolby Digital Plus, indicated in bits 7 to 3) as well as the maximum number of decoded output channels on the sink device (bits 0 to 2). Byte 2 is used to indicate the coded sample rate of the Dolby Digital Plus stream. Calbookaddict 20:55, 15 November 2007 (UTC)

[edit] History?

When was dd+ first introduced? Or what other dates are available? Thx, Daniel.Cardenas (talk) 18:54, 15 January 2008 (UTC)