DVD sound - why is it so poor?

caesar · Apr 12, 2011

Anyone know why DVDs sound so crappy (despite our minds filling in the audio with the visual details)? Thanks

amirm · Apr 12, 2011

Sure. Typical sound track on DVD is 384/440 Kbps Dolby AC-3. In that space, they are stuffing 5.1 channels, at 48 Khz and with 20 (?) of dynamic range. AC-3 is also an older algorithm so it is not as efficient as say, AAC.

For what it does, it is not too bad actually. But there is only so much you can do when you have 1/5 the data rate of the CD to stuff 2.5 times more channels at higher sampling rate and sample resolution.

JackD201 · Apr 13, 2011

DVD sounded great............when I got my first one. Then again all I was comparing it with was VHS and ((((((((((((gasp)))))))))))) Betamax.

Just another case of BD making DVD look and sound bad by comparison.

audioguy · Apr 13, 2011

I was coming from Laserdisc so I thought the sound was awesome. And maybe I'm not as picky about movie sound as I am about two channel. As noted, the movie itself pulls me away from being so "critical" so I'm measuring the whole "experience" rather than just the audio.

DonH50 · Apr 13, 2011

I used to not care about movie sound and still am much less sensitive than to music, and DVDs beat out every 8-track I owned (joking, never owned any, though my wife did), but after listening to a few blue-ray disc movies I do appreciate their much higher fidelity. In combination with the much better picture, I am buying mostly BDs now. Bloody marketeers...

caesar · Apr 13, 2011

amirm said:
Sure. Typical sound track on DVD is 384/440 Kbps Dolby AC-3. In that space, they are stuffing 5.1 channels, at 48 Khz and with 20 (?) of dynamic range. AC-3 is also an older algorithm so it is not as efficient as say, AAC.

For what it does, it is not too bad actually. But there is only so much you can do when you have 1/5 the data rate of the CD to stuff 2.5 times more channels at higher sampling rate and sample resolution.

Thanks. That makes a lot of sense. When I watch Jeff Beck at Ronnie Scott's through my Oppo, the sound is much, much worse than the CD recording. Watching his fingers move and the bassist strum the basss is quite cool, though.

What I find kind of interesting is that one often hears arguments that the CD technology is so poor because it was developed in 1979. I am kind of surprised that the people who developed the DVD did not allocate that much space for music.

caesar · Apr 13, 2011

Is the Blue Ray sound that much better than DVD sound? Thanks

vinylphilemag · Apr 13, 2011

caesar said:
Is the Blue Ray sound that much better than DVD sound? Thanks

It depends on the title, but Blu-ray has the potential for MUCH better sound quality than DVD: up to 8 channels of uncompressed (or losslessly compressed) audio at higher bit rates and depths than are available on DVD.

amirm · Apr 13, 2011

caesar said:
Is the Blue Ray sound that much better than DVD sound? Thanks

Yes. For one, the data rate for Dolby Digital when it exists is 640kbps. Sadly, they capped it at that.

But, they allow two different lossless audio codecs: Dolby TrueHD and DTS-MA-HD. Both are like Flac, etc. when compressing your music and reproduce what is put in there. You can also have uncompressed PCM although that just wastes space over these codecs (is a help for a player which doesn't decode these optional codecs).

Note that the above are player capabilities. It is up to the content author to decide what to use. They can put the same sound as DVD if they like although they do not as a rule. Reviews specify the audio rate as does the back jacket.

RBFC · Apr 13, 2011

Jeff Beck: Live at Ronnie Scott's sounds incredible with DTS-MA 5.1 on the Blu-ray. The 2.0 LPCM track is excellent too, and most likely an exact copy of the CD release.

Lee

DonH50 · Apr 13, 2011

In my limited experience, well-mastered new BD titles have MUCH better sound than DVDs. Older titles, well, for me a miixed bag, much like remastered CDs. In some cases there is a significant step up in sound quality; in others, it sounds like all they did was port it from the DVD and there is very little if any improvement.

FWIWFM - Don

rbbert · Apr 16, 2011

DVD's can have up to 24/96 LPCM stereo, or 24/192 stereo (for DVD-A's). DTS 5.1 encoding has a bit rate of about 750 kbps (IIRC), giving it noticeably better sound than Dolby Digital.

Bluray surround sound can be clearly better than DVD sound, similar to the improvement in picture quality with BD over DVD. There's no reason a DVD can't have stereo sound essenitally identical to BD, though.

JackD201 · Apr 17, 2011

True, but will there be any space left for video content?

amirm · Apr 17, 2011

JackD201 said:
True, but will there be any space left for video content?

It is not just space but peak rate. You can't exceed 10 mbit/sec on DVD. As an example, stereo PC 24bit/96 Khz requires 4.6 mbit/sec just for audio. For video, we like to have high peak rate so that we can achieve good quality. Using that audio track, our peak can only be 5.4 mbit/sec which is pretty low for the MPEG-2 video codec used there.

NorthStar · Apr 17, 2011

The first DVDs with dts audio soundtracks by Universal Studios were encoded at 1.5 Mbps. ...Not too shabby at all.

But then, there was no Special Features at all on those DVDs.

* And then you had those Superbit DVDs by Columbia Studios, with better Sound (dts at 754 Kbps), and also better Picture with a higher average than standard DVD (up to 8 Mbps).
...And again no Special Features at all; unless a second disc was included.

** Then you have DVD-Audio, with DVD picture quality,
but with High Res Audio up to 192kHz/24-Bit for 2-channel Stereo (96kHz/24-Bit for 5.1-ch.).
And you need a Universal DVD or BD player for that (or a Panasonic DVD/DVD-Audio player).

*** Disc Capacity; that's what it's all about, and Blu-ray will eventually increase that with "Holographic layers".
...It is already at the gates of reality.

...The entire Lord of the Rings Extended Editions Trilogy on one single disc!

Bruce B · Apr 18, 2011

JackD201 said:
True, but will there be any space left for video content?

Who cares about video??

NorthStar · Apr 18, 2011

Blu-ray High Res Audio only?

kach22i · Apr 18, 2011

audioguy said:
I was coming from Laserdisc so I thought the sound was awesome.

Actually, Laserdisc is known for having better sound than DVD's.

I've decided to keep my Laserdisc as a museum piece.

JackD201 · Apr 18, 2011

Bruce B said:
Who cares about video??

I was staying within the context of the OP Bruce.

DVD sound - why is it so poor?

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