Hi
Grateful if anyone could explain to me what the difference is between multi channel sound as used in DOM to create 5.1 sound and the same audio source when encoded to Dolby Digital surround sound?
The mystery is that I can play the 5.1 soundtrack from the DoM DCP on my PC with a 5.1 speaker setup using the Neo DCP player on my PC's 5.1 speaker system.
If however I Dolby encode the same source audio file as used to make the DCP using the TMPG encoding software, I cannot get the resultant sound file to play surround on my PC 5.1 speakers or on my surround sound home movie system. All I get is front left/right/center?
Its boiling my brain so any suggestions/comments gratefully received
Confused about sound
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Carsten
- Posts: 2665
- Joined: Tue Apr 15, 2014 9:11 pm
- Location: Germany
Re: Confused about sound
Multichannel sound is using separate/discrete channels, e.g. six for 5.1
'Dolby Surround' in this case means matrix encoded sound. It combines discrete channels (4,5,6...) into an Lt/Rt file (you may call it stereo) and applies special phase, frequency, level and delay calculations on it, so that a suitable Dolby Surround decoder can recreate the original multichannel representation (as far as possible) during playback. This encoding/decoding is not perfect, so a Dolby Surround multichannel mix is always a lesser representation compared to a discrete multichannel mix.
https://en.wikipedia.org/wiki/Dolby_Pro_Logic
The advantages of Dolby Surround are, that you can use a lower bandwidth/stereo only storage/transmission/playback channel to transport a surround mix, and also that it is stereo compatible, e.g. you can play it on non-multichannel/surround setups without channels missing (e.g. center and surrounds can be heard, although not on their native speakers). It was used a lot on analog sound 35mm film, because it allowed cinemas with a Dolby Surround setup to play the same prints as older cinemas with a stereo or even mono setup. It was also possible to put surround sound on simple VHS stereo tracks.
You are hearing the stereo/Lt-Rt only because your playback system does not have a Dolby Surround Decoder. If e.g. you would pipe your L/R playback signal into a surround capable AV receiver or similar audio playback hardware and activate Surround/ProLogic,etc, it would play in decent surround. Some audio playback hardware, soundcards, plug-in systems etc. will also allow you to spread matrix encoded sound to 5.1 outputs.
In digital cinema, Dolby Surround or other encoding methods have become redundant, actually they are sort of 'prohibited'.
http://isdcf.com/dcnc/home/appendix-4-a ... ation.html
Because many/most cinemas nowadays have sound processors that do either not allow surround decoding, or are not setup to apply it arbitrarily. As such, Dolby Surround is gone from modern cinema. DCI/DCP offers 16 channels of high quality audio, full bandwidth, high dynamics, noise free. No reason to use matrix encoding any more.
Dolby Digital/AC3/dts and Dolby ATMOS is a completely different thing. Only ATMOS is relevant in digital cinema nowadays.
- Carsten
'Dolby Surround' in this case means matrix encoded sound. It combines discrete channels (4,5,6...) into an Lt/Rt file (you may call it stereo) and applies special phase, frequency, level and delay calculations on it, so that a suitable Dolby Surround decoder can recreate the original multichannel representation (as far as possible) during playback. This encoding/decoding is not perfect, so a Dolby Surround multichannel mix is always a lesser representation compared to a discrete multichannel mix.
https://en.wikipedia.org/wiki/Dolby_Pro_Logic
The advantages of Dolby Surround are, that you can use a lower bandwidth/stereo only storage/transmission/playback channel to transport a surround mix, and also that it is stereo compatible, e.g. you can play it on non-multichannel/surround setups without channels missing (e.g. center and surrounds can be heard, although not on their native speakers). It was used a lot on analog sound 35mm film, because it allowed cinemas with a Dolby Surround setup to play the same prints as older cinemas with a stereo or even mono setup. It was also possible to put surround sound on simple VHS stereo tracks.
You are hearing the stereo/Lt-Rt only because your playback system does not have a Dolby Surround Decoder. If e.g. you would pipe your L/R playback signal into a surround capable AV receiver or similar audio playback hardware and activate Surround/ProLogic,etc, it would play in decent surround. Some audio playback hardware, soundcards, plug-in systems etc. will also allow you to spread matrix encoded sound to 5.1 outputs.
In digital cinema, Dolby Surround or other encoding methods have become redundant, actually they are sort of 'prohibited'.
http://isdcf.com/dcnc/home/appendix-4-a ... ation.html
Because many/most cinemas nowadays have sound processors that do either not allow surround decoding, or are not setup to apply it arbitrarily. As such, Dolby Surround is gone from modern cinema. DCI/DCP offers 16 channels of high quality audio, full bandwidth, high dynamics, noise free. No reason to use matrix encoding any more.
Dolby Digital/AC3/dts and Dolby ATMOS is a completely different thing. Only ATMOS is relevant in digital cinema nowadays.
- Carsten
Last edited by Carsten on Sun Mar 25, 2018 9:26 pm, edited 1 time in total.
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tba
- Posts: 30
- Joined: Mon Jan 15, 2018 4:20 pm
Re: Confused about sound
That clears things up nicely, thankyou