Lossless DVD Surround Sound?

[powerstone05]

Does anyone know a format that supports lossless surround sound (5.1)? If possible maybe if a ripper can rip it from a DVD directly into the lossless format?

[redwudz]

I'm not sure what you mean by 'lossless'. Outside of maybe PCM audio or similar, all audio formats could be considered fairly 'lossy', including AC3 5.1 audio from a DVD.

If you just mean that you don't want to lose any more quality, just keep the 5.1 audio from a DVD in the same format.

If you are converting the video to a format like Xvid or Divx, you might look to Aud-X. It allows you to use a 5.1 format with a Xvid or Divx. But it will only play back in 5.1 on a computer. A standalone Divx player will play only stereo MP3, AFAIK.

EDIT: As BJ_M pointed out:

my nad dvd player plays xvid w/ ac3 5.1 -- so do others

I stand corrected. Then you may be able to use the AC3 5.1, even with a Divx player.

[BJ_M]

my nad dvd player plays xvid w/ ac3 5.1 -- so do others

[nwo]

I seen a lot of old UK music dvd have a MPEG 5.1 track would that be more lossless than 5.1 Dobly Sound.

[guns1inger]

[quite]I seen a lot of old UK music dvd have a MPEG 5.1 track would that be more lossless than 5.1 Dobly Sound[/quote]

No, it isn't. And depending on who you ask, the quality of mpeg1-layer2 audio may well be inferior. If you already have an AC3 5.1 audio track you aren't going to make it sound any better.

[powerstone05]

Well I've noticed that DTS takes up more space than an Ac3 so I'm thinking "It must be lossless or better quality than an AC3. But another part of me says "It's not a compressed file."

[guns1inger]

DTS isn't lossless ,but it is compressed less than AC3. Most 5.1 AC3 is compressed at 384 or 448 kbps, whereas most DTS audio is compressed at 768 kbps. This is still around 50% of 2 channel uncompressed PCM audio.

Is it better quality ? It depends. Sometimes DTS tracks are mixed specifically, other times they are the same track as the AC3 version, encoded differently. DTS generally sounds louder, which most untrained people equate to be better quality. A good DTS mix can have better clarity because it has more data to play with, however this is moot for most people because there amps and speakers aren't capable of exploiting the difference.

Finally, there is still the basic laws of lossy compression : what has been lost cannot be regained. If you have AC3 5.1 @ 448 kbps, converting it to a lossless format will not make it better.

I believe that LPCM audio supports up to 7 channels for DVD Audio, but this is not available to DVD video simply because it would leave little to no bitrate for the video.

[powerstone05]

So you're saying that there is basically no lossless sound on a DVD because it would take up almost the whole disc?

[guns1inger]

Pretty much, yes. LCPM is lossless (well, as lossless as digital can be at these sample rates) and records at 1536 kbps for 2 channels. For 5.1 PCM a 90 minute film would have to be encoded at around 3050 kbps for the video, which is getting down into half-D1 territory.

However I do not believe the DVD Video Spec allows for more than 2 channels in LPCM.

[BJ_M]

2 channel only === but you can use use higher sample/bit rate @ 96khz/24bit , even up to 192 if your dvd player supports it ..

and if you can create it / author it


5,1 is limited to 96khz on dvd-a disks

[Cornucopia]

No, the DVD spec DOES allow for multichannel LPCM (that is, more than stereo/2ch), but there are limits to the bitrate (6144kbps, IIRC) which mean it can't be more than 16bit, 48kHz. (No higher bitdepths, samplerates)

What makes things worse, is that basically there is no known, documented settop player that recognizes such a disc, and there are VERY FEW tools that allow for authoring with those specs.

If you're really such into High quality, Lossless, Multichannel audio, you probably ought to go the DVD-Audio route instead of DVD-Video.

Scott

[BJ_M]

multichannel LPCM (and SDDS for that mater - also permitted) never was actually implemented in a player, so pointless. why i said 2 channel only ...

though u are technically correct ......

[Cornucopia]

Yeah, it's like talking about whether JetPaks are allowable in Urban Areas or not...

Although, I would think it could be quite possible for a software player to be made that implements this--VLC, maybe?

Scott

[jman98]

DTS does high frequency rolloff above (I think) 17000 Hz. I am not aware of Dolby doing any such rolloff. Audiophiles could make a point that while DTS uses higher bit rates, it might actually be more lossy than AC3 as a result of this rolloff. Whether you could actually hear the sounds above 17000 Hz or not is a very good question, which depends on your age and some other factors.

Multichannel MPEG audio has long ago been abandoned by everyone, including Philips who invented it. I'm not sure if there are any receivers made by any company currently that can correctly decode the format. MPEG audio is not bad at all and maybe could have given Dolby a run for the money if more playback devices had supported it in multichannel mode. I have an Australian DVD from some years ago that has 5.1 MPEG audio and AC3 and my Pioneer amp can only decode the 5.1 MPEG stream as stereo. Multichannel MPEG audio was designed to decode into stereo if the playback device doesn't support decoding it into 6 channels.

powerstone05 - nobody seems to understand what you REALLY want to do. If you just want to rip DVDs and keep the best audio, I'd advise keeping the DTS when possible, assuming your playback device supports it. If your intention is to rip a DVD and somehow convert the audio portion into "something better", you can't do that. You can't convert lossy audio formats, no matter how high the quality, into lossless formats. Well, you can, but all you have is an exact lossless copy of the original format, not anything better. If you are looking for audio formats that are superior to DTS and AC3, you need to move into either HD-DVD or BluRay where both Dolby and DTS have announced support for superior audio formats. I think both formats also support multichannel LPCM right now as well.

[powerstone05]

well I originally thought that Video DVDs (More like a Music DVD) contained lossless audio. However, people have responded that the video has taken up most of the room so the audio has to be "lossy" or it won't fit the disc. So, the DVD Audio must have lossless sound because most of them run on time, not size and they support multichannels. too bad, the DVD never came out on DVD-A.

[jman98]

well I originally thought that Video DVDs (More like a Music DVD) contained lossless audio. However, people have responded that the video has taken up most of the room so the audio has to be "lossy" or it won't fit the disc. So, the DVD Audio must have lossless sound because most of them run on time, not size and they support multichannels. too bad, the DVD never came out on DVD-A.

DVD Audio supports lossless audio because all of the disc (remember, DVD Audio can use dual layer discs if necessary) is used for audio encoding. Although DVD Audio discs can support video as well, this isn't done much because it takes away space. Video on DVD Audio discs, if it even exists, is usually 20 minutes or less. As stated, the only lossless audio format on video DVD is LPCM which is only 2 channels.

[BJ_M]

even dvd LPCM can be siad to be lossy - since it is a digital format converted (usually) from a higher sample rate digital and/or analog source ---

there is a substantial audio diff. between 16 and 24bit ....

[edDV]

All this becomes more interesting once we leave the constraints of DVD and move on to HD/BD DVD authoring and beyond.