Compressor and surround encoding

[Captin Al]

I just wondered if anyone has the time to explain an idiots proof guide to encoding using Compressor. I am having some level problems after encoding.

I have a calibrated system and playback is fine it's just after I have encoded and put a DVD together with Studio Pro the levels seem different, I can monitor playback through the digi out of the mac to a surround amp so can tell straight away the AC3 file is wrong. maybe I am mixing down too loud, as I have the surround mix quite limited at the mo and am a bit confused at what levels I can put in.

I have tried lots of setting, got no compression, dialog norm set to -31 so it shouldn't change anything..

Appreciate any help..

[Smallbudgetguru]

Where is your mix peaking at? Whats the RMS roughly? Are you mixing into a limiter?

Also when you use compressor which settings are you choosing?

[Captin Al]

Originally Posted by Smallbudgetguru

Where is your mix peaking at? Whats the RMS roughly? Are you mixing into a limiter?
Also when you use compressor which settings are you choosing?

mix is peaking at -1db on the L & R at it's highest, yep mixing though a multichannel limiter.

I think I've tried most settings but settled on these, I took the Dolby standard and made it 448, with no compression.

Description: Dolby Digital audio at 384 Kbps
File Extension: ac3
Estimated size: 201.6 MB/hour of source
Audio Encoder
Format: AC3
Sample Rate: 48.000kHz
Channels: 6
Bits Per Sample: 16
Target System: DVD Video
Data Rate: 448 kbps
Compression Preset: None
Audio Coding Mode: Selected
Audio Coding Mode: 3/2 (L, C, R, Ls, Rs)
BitStream Mode: Music and Effects
Center Mix Level: -3dB
Surround Mix Level: -3dB
Dolby Surround Mode: None
Room Type: Small
LFE Exists: Yes
Dialog Normalization: -31 dbFS
Copyright Exists: Yes
Original Content: Yes
Audio Production Information Exists: Yes
API Mix Level: 10
RF Overmodulation Protection: Off
Channel Bandwidth Lowpass Filter: On
DC Highpass Filter: On
LFE Channel Lowpass Filter: On
3dB Attenuation: Off
phase 90: Off
Deemphasis: Off

[neilwilkes]

Originally Posted by Captin Al

mix is peaking at -1db on the L & R at it's highest, yep mixing though a multichannel limiter.

I think I've tried most settings but settled on these, I took the Dolby standard and made it 448, with no compression.

Description: Dolby Digital audio at 384 Kbps
File Extension: ac3
Estimated size: 201.6 MB/hour of source
Audio Encoder
Format: AC3
Sample Rate: 48.000kHz
Channels: 6
Bits Per Sample: 16
Target System: DVD Video
Data Rate: 448 kbps
Compression Preset: None
Audio Coding Mode: Selected
Audio Coding Mode: 3/2 (L, C, R, Ls, Rs)
BitStream Mode: Music and Effects
Center Mix Level: -3dB
Surround Mix Level: -3dB
Dolby Surround Mode: None
Room Type: Small
LFE Exists: Yes
Dialog Normalization: -31 dbFS
Copyright Exists: Yes
Original Content: Yes
Audio Production Information Exists: Yes
API Mix Level: 10
RF Overmodulation Protection: Off
Channel Bandwidth Lowpass Filter: On
DC Highpass Filter: On
LFE Channel Lowpass Filter: On
3dB Attenuation: Off
phase 90: Off
Deemphasis: Off

Can I ask why the first line says audio stream at 384kbps, yet further down, it says 448kbps?
It is best to avoid 384 at all costs - the high frequencies go unidirectional at 10kHz and the transient smearing is awful.

[Captin Al]

Originally Posted by neilwilkes

Can I ask why the first line says audio stream at 384kbps, yet further down, it says 448kbps?
It is best to avoid 384 at all costs - the high frequencies go unidirectional at 10kHz and the transient smearing is awful.

It's just the preset name, I change it too 448..

[kk@jamsync.com]

Originally Posted by Captin Al

mix is peaking at -1db on the L & R at it's highest, yep mixing though a multichannel limiter.

I think I've tried most settings but settled on these, I took the Dolby standard and made it 448, with no compression.

Description: Dolby Digital audio at 384 Kbps
File Extension: ac3
Estimated size: 201.6 MB/hour of source
Audio Encoder
Format: AC3
Sample Rate: 48.000kHz
Channels: 6
Bits Per Sample: 16
Target System: DVD Video
Data Rate: 448 kbps
Compression Preset: None
Audio Coding Mode: Selected
Audio Coding Mode: 3/2 (L, C, R, Ls, Rs)
BitStream Mode: Music and Effects
Center Mix Level: -3dB
Surround Mix Level: -3dB
Dolby Surround Mode: None
Room Type: Small
LFE Exists: Yes
Dialog Normalization: -31 dbFS
Copyright Exists: Yes
Original Content: Yes
Audio Production Information Exists: Yes
API Mix Level: 10
RF Overmodulation Protection: Off
Channel Bandwidth Lowpass Filter: On
DC Highpass Filter: On
LFE Channel Lowpass Filter: On
3dB Attenuation: Off
phase 90: Off
Deemphasis: Off

Probably on the decode side, the decoder is reverting to its own compression preset (whatever that is). On many decoders you can override this, but I generally go with Music Light, since, if you mix in a cal'd room, it's not likely you'll hear the effect at conservative mix levels. Leaving off a compression preset can cause all kinds of problems.

[mikevarela]

Your monitoring situation seems a little weird.

You say monitoring through digi, mac and HiFi?

Maybe you're getting a fold down into the amp because you're using digital (spidf) out?

Wondering how you can monitor through digi? (digidesign?)

Normally, without plugins, you'd have to either have a Dolby box, or a home 5.1 setup, or out of the mac into the home 5.1 via the DVD Player app - not with Pro Tools

[kk@jamsync.com]

Oops, Mike's right about the monitoring chain, since you're coming out of the Mac. So you're sending DD out the S/PDIF port and the surround "amp" is decoding? Or...? Otherwise you may be downmixing internally and the surround amp may be *dematrixing* downmixed stereo.

Bear in mind, though, that if you have no compression preset, and you have high levels, the encoder may go into "automatic overload protection". This can cause distortion and even mute the program material. It's one reason to use the proper compression preset.

Here's a handy pdf from Minnetonka Audio that gives some insight to what may be happening on the encode side.

http://www.minnetonkaaudio.com/info/...Guidelines.pdf

[minister]

Originally Posted by Captin Al

I have a calibrated system and playback is fine it's just after I have encoded and put a DVD together with Studio Pro the levels seem different, I can monitor playback through the digi out of the mac to a surround amp so can tell straight away the AC3 file is wrong. maybe I am mixing down too loud, as I have the surround mix quite limited at the mo and am a bit confused at what levels I can put in.

Your system is calibrated. But you are checking payback in a consumer environment. Did you calibrate this? The decoding surround amp is likely a -10 device.

If you are playing the DVD back on a Mac in DVD Player, did you "Disable Dolby dynamic range compression"?