When we go to imdb.com and take a look at “Technical Specifications” we can find this (SOUND MIX):

Dolby, Dolby Stereo, Dolby SR, Dolby Digital, DTS…

I’d like to know the exact number of channels of each sound format to be sure that their blu-ray releases have the original mix. For instance, Robocop, 1987 (IMDB):

Sound Mix - Dolby SR (35 mm prints) | 70 mm 6-Track (70 mm prints) | DTS (special edition)

So, 70 mm (blow-up) 6 track, but, 35 mm? How many channels? Then, I went to blu-ray.com:

English: Dolby Digital 4.0 (Original) (Robocop)

Therefore, is Dolby SR always 4 channels? and what about the other sound formats? From what I understand…

Dolby = ?
Dolby Stereo = 4.0
Dolby SR = 4.0
Dolby Digital = 5.1
DTS = 5.1

One more example, Child’s Play, 1988 (IMDB):

Sound Mix - Dolby Stereo

Blu-ray (MGM):

AUDIO:

Codec Language Bitrate Description

DTS-HD Master Audio English 3687 kbps 5.1 / 48 kHz / 3687 kbps / 24-bit (DTS Core: 5.1 / 48 kHz / 1509 kbps / 24-bit)
Dolby Digital Audio English 224 kbps 2.0 / 48 kHz / 224 kbps / DN -4dB / Dolby Surround
Dolby Digital Audio Spanish 448 kbps 5.1 / 48 kHz / 448 kbps / DN -4dB
Dolby Digital Audio French 224 kbps 2.0 / 48 kHz / 224 kbps / DN -4dB / Dolby Surround
Dolby Digital Audio Portuguese 448 kbps 5.1 / 48 kHz / 448 kbps / DN -4dB
Dolby Digital Audio English 224 kbps 2.0 / 48 kHz / 224 kbps / DN -4dB
Dolby Digital Audio English 224 kbps 2.0 / 48 kHz / 224 kbps / DN -4dB

Dolby Digital Audio English 224 kbps 2.0 / 48 kHz / 224 kbps / DN -4dB

Blu-ray (Shout Factory)

AUDIO:

Codec Language Bitrate Description

DTS-HD Master Audio English 3660 kbps 5.1 / 48 kHz / 3660 kbps / 24-bit (DTS Core: 5.1 / 48 kHz / 1509 kbps / 24-bit)
DTS-HD Master Audio English 2095 kbps 2.0 / 48 kHz / 2095 kbps / 24-bit (DTS Core: 2.0 / 48 kHz / 1509 kbps / 24-bit)
Dolby Digital Audio English 192 kbps 2.0 / 48 kHz / 192 kbps / DN -4dB
Dolby Digital Audio English 192 kbps 2.0 / 48 kHz / 192 kbps / DN -4dB
Dolby Digital Audio English 192 kbps 2.0 / 48 kHz / 192 kbps / DN -4dB
Dolby Digital Audio English 192 kbps 2.0 / 48 kHz / 192 kbps / DN -4dB

I can’t see 4 channels. No release has included the original mix?