Any reason to keep surround sound for movie rips?

[hogger129]

Hello everyone. I am doing some rips of my DVD and BD collection for personal backup/playback and was wondering if there is any reason to keep the surround sound.

I am playing back through my WDTV Live, TV has a soundbar. I will likely also be playing these on my laptop. I do not have a surround sound setup. I would imagine converting to AAC stereo would save me tremendous amounts of space as well.

Also, since it is stereo, does that mean there is no bass channel? Is it just matrixed in with the other two channels the same way music is, it's just not a separate channel like 5.1?

Would I gain anything by using Pro Logic II instead of just regular stereo?

Thank you.

[ndjamena]

There is absolutely no reason to keep surround sound if you don't plan on playing it on a surround sound system, other than quality lost if re-encoded with a lossy codec.

Stereo is 2.0. The LFE and the surround channels will be merged into those 2. channels.

The channels won't be 'matrixed' unless you use Pro Logic II (Dolby Surround), and matrixing will only be of any use if you play it back on a surround sound system at some point.

[jagabo]

I would imagine converting to AAC stereo would save me tremendous amounts of space as well.

Tremendous? No. A little, yes.

[hello_hello]

There's no reason to keep surround sound. I don't have a surround sound system and I don't even particularly like surround sound but I do keep it. Maybe one day I'll change my mind. If I do I won't need to rip and re-encode it again. Plus it lets me choose how it'll be downmixed on playback (using my PC).

When you downmix to stereo the LFE channel is usually included, but not always. It's pretty much optional so it depends on the program doing the downmixing. It tends not to contain anything not already in the other channels, so you could look at it as just providing a bass boost. I mainly use my PC for playback and I've set the decoder not to include the LFE channel, but it's personal preference.

How much space you'll save is probably fairly relative to how much space you're using in the first place. When the average DVD re-encode might be 1.5GB for the video, and for 1080p you can be in the vicinity of 8GB or more, the space saved by downmixing the audio to stereo seems neither here nor there to me (it depends on the encoder quality/bitrate used). I don't keep DTS as it's fairly space consuming (generally over 1GB for a movie) but I'd either convert it to 5.1ch AAC or keep the original 5.1ch AC3 instead.

I can't see the point in downmixing to Prologic 2. The idea is it can still be decoded to surround sound but it's never going to be as good as the original 5.1ch. When I was using AutoGK a lot (which downmixes to Prologic 2) on the very odd occasion I noticed it'd do something odd to the dynamics. A loud gunshot would be quiet.... that sort of thing. I only noticed it very occasionally and maybe it wasn't the downmixing to Prologic which caused it as such. It'd then be converted to MP3, so I sometimes wondered how well lossy compression does with Prologic 2, especially at lower bitrates.

[hogger129]

Thanks everyone for your input. I will settle for AAC 2.0 then -- encoded from the highest quality track I have on the source disc of course.