Stargate SG-1 DVDs and 5.1 audio setups?

[Ragitsu]

Hello.

Apparently, the DVD only seasons of Stargate SG-1 (and, I assume, the Blu-Ray releases of Seasons 8, 9 and 10) feature 5.1 audio. I am curious to find out if any of you have been fortunate enough to have listened to those pre-HD seasons on a 5.1 audio arrangement. If so, please share with us just how good they sound.

[Britta]

Season 1 on DVD only has stereo audio, the rest have 5.1 audio. I can't speak to the actual quality of these 5.1 tracks though, as I don't have a 5.1 system.

Seasons 8-10 didn't get Blu-ray releases at the time despite existing in HD, but the whole series was recently released on Blu-ray by a company called VEI. There are apparently problems with these though. For a start they're upscaled, at least for seasons 1-7. Also, excessive digital noise reduction removes a lot of detail, and they botched the 5.1 audio except for the first season. The other seasons' 5.1 tracks are apparently just the stereo tracks duplicated weirdly across the other channels.

[gturner]

I've looked at the audio in Audacity, and it's actually in mono. The exact same track is on all the channels except the low frequency effects channel, which is blank. I probably noticed it because I use headphones and can easily tell mono from stereo. Checking it in Audacity confirmed it, both by looking at the waveforms (which should have different peaks and shapes), and then by inverting a channel and then summing it with the others, which results in perfect cancellation.

It has to be an oopsie.

[billtkd]

The earlier DVD releases had 5.1 where possible. It should have been possible to revisit all the audio stem and produce a proper 5.1 mix, but they didn't.
The '5.1 audio' on recent blu-ray releases are merely stereo* spread to all 5 speaker (L+R on the centre channel) and nothing on the VLF channel. This is presumably a mistake, inexcusable because:

• The DVDs had the correct surround mix.
• Even if they had only used a stereo source, it is relatively easy to upmix stereo to 5.1. Most home cinema systems do a reasonably job of it, with Dolby Pro-Logic or DTS-Neo decoding.

*I am taking the word of other reviewers for this, because I don't have the discs. If gturner is right and it's mono, that is even more inexcusable. (BTW, in Audacity, you don't have to just look at the waveform. The 'Vocal reduction and Isolation' effect had be set to 'Analyse' and it will give you a value for the percentage similarity between the channels.)*

The video on Seasons 1-7 on the blu-rays is merely (and apparently badly) upscaled SD. The originals of those seasons were recorded on film, which could be scanned to ultra-HD, if anyone wanted to spend the time and money on it.

[gturner]

Okay, I did that, and Audacity confirmed it, saying:

Re: the left and right channel.
<blockquote>The left and right channels are correlated by about 100%. This means:
- The two channels are identical, i.e. dual mono.
The center can't be removed.
Any remaining difference may be caused by lossy encoding.</blockquote>

I combined the right and center channel and got the exact same message. So the first three channels are all the same.

Then I checked the left-surround and right-surround channels against each other and got the same message. So there's a mono-track on the surround channels.

But when I checked a surround channel against the left, right, and center I got a very different message.

<blockquote>The left and right channels are correlated by about 1%. This means:
- The two channels are almost not related.
Either you have only noise or the piece is mastered in an unbalanced manner.
The center extraction can still be good, though.</blockquote>

Well, I tried comparing it to the old DVD stereo channels, which isn't going to be perfect, and got a pretty good correlation between the old stereo right channel and the BluRay surround channels.

So that's probably what's happened. The old left stereo is on channels 1, 2, and 3, and the old right channel is on 5 and 6. Channel 4, low frequency effects, is of course blank.

So anyway, what got me to this point was that I went through all ten seasons, carefully syncing the old stereo audio to the new video for seasons 1-7, which every now and then required a multiple splice, but not often. For seasons 8, 9, and 10 I fell into a rhythm of resyncing the old stereo audio (to within a few samples at 48KHz), then using the aforementioned Audacity Vocal Reduction and Isolation tool to isolate the center and put that on the center channel. Then I rolled off the center channel at about 80 Hz using one equalizer pass and then the low-pass filter, and put that on the low frequency channel. Then I used "remove center" on the old stereo track to generate the two surround channels. It took me about a week to do the whole series.

It sounds great in the headphones, but I don't own a surround sound system so I'm not really sure what the result actually is. ^_^

Now I can go back to fixing the subtitles on Andromeda. I'm up to season 3. I already redid all the subtitles for Sanctuary, posting my new SDH ones to <i>tvsubtitles.net</i> under "GLT". I don't think I'll bother doing SDH for Andromeda, but posted the regular subs for the first two seasons.

[Angela V]

I have the original DVDs. I'm actually on a rewatch right now (I'm on season 5). I have found the 5.1 sound excellent on them. Which makes me cringe when I had heard about the new BluRay set messing up the sound.