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Old 10-06-2004, 05:00 PM
Philip Colmer
Thoughts Media Review Team
Philip Colmer's Avatar
Join Date: Aug 2006
Posts: 599
Default SurCode Dolby Digital 5.1 for Premiere Pro reviewed

Product Category: Audio encoder
Manufacturer: Minnetonka Audio Software Inc
Where to Buy: From within Premiere Pro
Price: $295.00 USD
System Requirements: As for Premiere Pro. A 5.1 sound card plus speakers is recommended for checking the surround mix.

  • Seamless integration into the video to DVD workflow;
  • Offers access to the various Dolby Digital settings.
  • Requires a good understanding of the encoding guidelines.
A software-based Dolby Digital 5.1 encoder that works directly within Premiere Pro, gives you full control over the encoding parameters and won't break the bank to give you the ability to create DVDs with full surround sound.

Read on for the full review!

The Pace Of Technology
When I first bought a camcorder, home videos were edited together by having two video decks and copying the bits you wanted from one deck onto a master tape in the second deck. If you were really flash, you might have a hardware title unit or, even better, a transitions unit!

Roll forwards maybe five or six years and I'd bought myself a PC with a realtime editing card to do editing on the computer of my video, with so many transitions and effects at my disposal, it was all I could do not to go into transition overload. Wind the clock forwards one more time by just four years to the current day. Today's hardware is capable of handling more simultaneous video tracks in real time and burning videos onto DVDs for playing in the living room at higher quality than VHS.

Now I realise that the above scenario took ten years but nowadays, we don't really think twice about having living rooms with surround sound speaker installations, widescreen TVs and DVD players giving us a reasonable stab at reproducing the cinema experience. The pace of change to consumer electronics and the growth in the power of PCs has been extraordinary.

Until recently, though, home movies have been definitely stuck with stereo soundtracks. Recent improvements to some of the DVD authoring tools have finally given us the encoding capability to produce Dolby Digital soundtracks but the question has often been how do you create the audio to push into the encoding process?

Adobe provides two tools to solve that problem - Audition will allow you to take a multitrack session and produce a full 5.1 mix, albeit in wave files, whilst Premiere Pro will allow you to work directly on a 5.1 audio mixer, positioning your sounds where you want. Encore DVD, Adobe's DVD authoring tool, will produce Dolby Digital soundtracks in stereo, but how can you go on from a Premiere Pro project with 5.1 audio to produce a DVD with a Dolby Digital 5.1 soundtrack?

The answer is SurCode from Minnetonka Audio. This software plugin works directly within the Adobe Media Exporter to allow you to take the audio in your Premiere Pro project and encode it.

Why Dolby Digital?
When the DVD specification was drawn up, the audio format was expressed in terms of mandatory and optional audio types. It is only possible to release a commercial DVD with an optional audio type (such as Dolby Surround) if the DVD has at least one soundtrack of a mandatory audio type (such as Dolby Digital).

Dolby Digital was first used in cinemas in 1992. It provides six channels - left, centre and right channels in front of you, left and right surround channels (typically located to the side and behind you) and a subwoofer or bass effects channel - the ".1" in 5.1.

Also known as AC-3 (third generation audio coding algorithm), Dolby Digital is a technology licensed from Dolby Laboratories. Dolby are (quite rightly) protective of their trademark and go through a licensing and certification process for all Dolby Digital encoders and decoders. Content created with a Dolby certified encoder is entitled to carry the Dolby Digital logo.

As to the question of why Dolby Digital over any other audio format ... a 3 minute uncompressed 5.1 soundtrack takes about 230MB. Dolby encoding reduces that to 12MB. In addition, of the choices available to DVD authors, the other common standard (PCM) is stereo only and does not compress as well.

Enter Stage Right ... SurCode
The reason why I started this review with a look back at how technology has changed is because not only am I amazed that we have today software encoders that allow me to sit at my computer and create a Dolby Digital 5.1 soundtrack ... but that I can buy it for $295!

The plugin is actually provided as part of Adobe Premiere Pro and you get three free goes at using it before you have to pay for it. Purchasing the software is done from within the plugin interface itself. You are presented with a system code and Minnetonka give you an activation code to unlock the plugin. This ties the plugin down to your specific installation at that time. If you reinstall the software or the OS, you may find that the system code changes and you have to ask Minnetonka for a new activation code. I don't know how long they would take to come back with a new code.

I understand from a posting on an Adobe forum that it is possible to get a USB dongle from Minnetonka, in which case the system code and activation code tie themselves to the dongle rather than your system, thus easing the pain of reinstalls or needing to use more than one system (although not more than one at a time).

Using the SurCode encoder is very straightforward. Simply fire up Adobe Media Encoder, pick SurCode for Dolby Digital as the codec, set the rest of the settings, click OK and away it goes. Some time later (depending on how long your project is), you have an ac3 file that can be dropped into Encore without any further processing and you're done.

Well, that's the basics. Truth be told, there are a lot of settings, as Figure 1 shows. I'm not going to go into all of them, but I will explain how some of them fit into the world that is Dolby Digital encoding. If you want more information, all of the settings get their names from Dolby so you can learn quite a bit by reading Dolby Digital Professional Encoding Guidelines [PDF].

Another document from Dolby's site - 5.1-channel Production Guidelines [PDF] - makes a good general purpose read if you want to know more of the background and how to set your system up properly.

I listed as a "con" on the front page of this review that using this software requires a good understanding of the encoding guidelines. That is the truth but, to be honest, there isn't a great deal that Minnetonka can do to ease that learning curve. It is a reflection of how technical Dolby Digital is in reality and, just like MPEG encoding for video, the settings you use are likely to vary according to the material you've got.

Figure 1: SurCode settings

Starting from the top, we have Audio Coding Mode. This lets you specify how many speakers you are encoding for, as shown in Figure 2. Although I've mentioned 5.1 a lot, Dolby Digital is capable of supporting a wide range of different speaker setups. The common ones are 5.1 (shown as 3/2) and Stereo (2/0).

Figure 2: Speaker options

With the exception of the first two options, the rest can optionally include the LFE - low frequency effects channel. This is a separate tickbox beneath the speaker selection because it is quite easy to have created a 5 channel mix without any LFE portion at all.

It is important to understand the distinction between the LFE channel and the signal that goes to your subwoofer. The LFE channel is a separate, limited frequency signal created through the mixing process and delivered alongside the main channels in the mix. The subwoofer signal is created in the decoder/amplifier as needed for the speakers that have been set up. This signal is created using bass management. Through bass management, a subwoofer signal may comprise bass from any channel or combination of channels - typically bass frequencies of 120Hz or less. It is therefore important to use the LFE channel with care as it can cause smaller systems to overload.

The Dynamic Compression preset is an interesting setting to experiment with. The idea here is to apply compression to the audio but using different settings according to the profile you choose. So, for example, if you pick Film Standard (the default), the attack threshold is 15dB and the decay threshold is 20dB, while for Speech, these figures are both 10dB.

The rest of the settings shown require quite an understanding of the encoding guidelines. In most cases, the defaults that SurCode provides will be good.

SurCode In Action
As with most encoders, be they audio or video, there isn't much action to be seen while they are getting on with their job. The results are what counts. In testing the plugin, it did a great job of encoding everything I threw at it, from speech to music.

If you've got a surround sound setup at home and the ability to burn a DVD, you might want to listen for yourself. I've taken the surround sound mix that was created for the Audition review and used SurCode to encode that mix into a Dolby Digital 5.1 track. I've then created a DVD image that you can download, burn onto a disc and play in your own environment.

NTSC DVD disc image (57MB)

PAL DVD disc image (57MB)

You should be able to use these images with any software that can burn a disc image onto a DVD. You may need to change the extension of the file if your disc writing software doesn't recognise ".iso". The image will work with any media that your player can support so you can use rewriteable discs if they are compatible.

If you are interested in breaking the stereo barrier, this is definitely the way to do it. Integrating Dolby Digital encoding directly into Premiere Pro makes the process a seamless part of the workflow you would normally use for DVD authoring.

The plug-in gives you control over all of the Dolby Digital encoding parameters thus giving you the power to get the best results. For the novice user, the default settings are going to do a good enough job without having to worry about the meaning of the various parameters.
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