What about audio channel no.7?

[Finkster]

Nowadays, some DVDs are released with a 7th audio channel (Dolby Digital EX, DTS 6.1)

(The new channel is for a speaker directly behind the listener, and demands new decoder-hardware if you want to play the mentioned DVDs in 6.1)

Does anyone have a clue what it takes to rip a 6.1 audio track from a DVD and play it correctly through the digital soundcard? (as we have done with 5.1 AC3 for some years now)

[Sycho]

Dolby Digital EX is a matrix format, like dolby surround, surround back matrixed into the surround left and surround right evenly, it will play back the same as a normal 5.1 track

dtsES has two formats, matrix and discrete, matrix is pretty much the same as Dolby Digital EX, but in a dts stream. Discrete uses dts wasted space to contain an extra channel which is also matrixed into the surround left and surround right, and removed on playback.

All of the Extended Surround formats will play back as a normal 5.1 track

[Finkster]

Well, I learned a little there...

You're actually saying that I should'nt give a sh.. about all the fancy mention of "6.1" when shopping DVDs? (and implicitly, should'nt bother with trying to rip the "6.1-track" either)

[Wilbert]

See http://hypercubemx.free.fr/html/the_audio_formats_jungle.html

Dolby Digital EX is a matrix format, like dolby surround, surround back matrixed into the surround left and surround right evenly, it will play back the same as a normal 5.1 track
Is there a way to extract the 7th channel, and make a 6.1 AC3?

About DTS ES 6.1 discrete:

Discrete uses dts wasted space to contain an extra channel which is also matrixed into the surround left and surround right (...)
Why? I mean, it is stored as 7 separate channels right (the other ones just 6).

[Sycho]

@Wilbert

It would be usless to extract the Surround Back channel because Dolby Digital cannot have another channel, that's why it is matrixed into the Surround Left and Surround Right

About dts, the standered 5.1 stream is only 5channel, the LFE is placed on the 80hz and lower portion of the surround channels
look at this (http://webapp.etsi.org/action%5CPU/20020827/ts_102114v010101p.pdf)

[Wilbert]

It would be usless to extract the Surround Back channel because Dolby Digital cannot have another channel (...)
Forgot about that, thanks.

But in theory it should be possible to extract the 6.1 dts [DTS ES 6.1 discrete] and mux it with avi? Do you know a movie with DTS ES 6.1 discrete?

[DIggedy]

if its a DTS-ES dvd, and you rip the dts stream, you are ripping the ES track as well... it's just specific frame header information that would tell the reciever to engage ES mode, which is embedded into the 5.1 track.

Also sycho regarding your sig.... DTS 96/24 most definitely is not the same filesize as a standard dts track!

[Sycho]

dts 96/24 has to be the same size (bitrate) as a regular dts track, or else the players and recivers would not play/understand it(96/24 is suppose to be back complient), correct me if i am wrong please

[specise_8472]

If you read the specs you were earlier quoting.
DTS 96/24 is regular DTS encoding with the extra data added.

QUOTE: On the decoder side core and extension parts of the encoded bit stream are fed to their respective sub-band decoders. The reconstructed core sub-band samples are added to the corresponding residual sub-band samples in lower 32 bands. The reconstructed residual sub-band samples in the upper 32 bands remain unaltered. Passing the resulting extension sub-band samples through the synthesis 64-band QMF filter bank produces the 96 khz sampled PCM audio.

So if your amplifier dosen't know about 96/24 sound then you will get normal DTS 48khz.

[Sycho]

but if it is regular dts, the extention is still there, and it is full of a hole lot of nothing, just reserved space that isn't used, all I am saying is that no matter, what dts format it is(except cinema) the extention will always be there, and the commpression is *probaly* more like 7:1 or higher (remember that dts can have compression of 3:1 to 40:1, I think)

[specise_8472]

As I take it to mean by the Patent.

Quote: The window size is set based upon the amount of compression, i.e the ratio of the transmission rate to the sampling rate, such that the amount of data encoded in each frame is constrained.
- However, as the number of channels is increased the amount of compression must also increase to maintain the desired transmission rate.
Endquote:

You will find that the encoders (surcode), to make life easier for themselves, will have set window sizes that the encoder uses to make it easier to encode. So if you encode 2 channels that compression rate lowers to fill the available space. And as you add channels the compression rate rises to suit. So always the same size file.

Now I hope the new NUENDO DTS encoder that is due out shortly? will implement a better more suited to the specs encoder.

edit: BTW DTS specs there is a seperate LFE channel encoded. Not derived or extrapolated from audio data.

Hope this helps

[Sycho]

thats kinda what i was trying to say, THE FILESIZE STAYS THE SAME