technical question about BD player

[John Kim]

Question:

I am playing a BD (Blu-ray disc) that has sound in Linear PCM format.

Somehow I feel that the DR (dynamic range) is compressed.

I heard DR will be ALWAYS COMPRESSED when playing DVD or BD, unless I extract digital signal out of the disc and connect it to an audio amp.

Is this true?

Thanks in advance.

John,

[John Kim]

For the audio reproduction, I only have an analog amp.

I think no matter what I do, no matter what I tweak, the sound I hear is always COMPRESSED.

Is there a way to fix this?

Or, do I need a digital amplifier??


...... (break)


Oh, by the way, I can read the digital audio signal from the BD via an optical line output and connecting it to my Denon CD Recorder (hit the "record" button without pressing "play"). This way, I think the sound is totally undistorted and uncompressed!!

Is this it???

WOW, the sound I am hearing is just AWESOME!!!

No compression at all!

I guess I will rush to Best Buy to get a digital amplifier tomorrow .

John,

P.S. Still, I cannot record the digital signal because it's copy protected.

[david johnson]

when i first saw this, i thought you were asking about bass-drum playing   

[John Kim]

when i first saw this, i thought you were asking about bass-drum playing   

yeah, I can play bass-drum!!

John,

[Damfino]

John, the optical out will not give you the full uncompressed sound. It may be better than stereo analog outs, but you will not get the full range unless you output the sound via the player's HDMI output. For example, if a Blu-ray disc has DTS HD Master audio, the optical out will only output the "core DTS" sound, which is comparable to the audio on a DVD.

There are some Blu-ray players with 5.1 analog outs which can connect to come receivers which have corresponding analog inputs (I have my SACD player connected this way). You would get uncompressed audio with that kind of setup; but amps/receivers with the 5.1 analog inputs and BD players with those outputs are becoming rare as more people adopt HDMI.

The linear PCM is not necessarily compressed at the source. Some of the best sound I have heard is on linear PCM tracks. I just think you are not getting the full bandwith of the PCM sound with your receiver. Most BD players have the option to output sound as Bitstream or PCM. I set mine to Bitstream, and let my receiver decode the audio. Or, I could set the player to PCM and let the player decode the 5.1 audio before it sends it to the receiver. It sounds the same, but the receiver will not light up with DTS HD Master on the front panel.

[John Kim]

John, the optical out will not give you the full uncompressed sound. It may be better than stereo analog outs, but you will not get the full range unless you output the sound via the player's HDMI output. For example, if a Blu-ray disc has DTS HD Master audio, the optical out will only output the "core DTS" sound, which is comparable to the audio on a DVD.

There are some Blu-ray players with 5.1 analog outs which can connect to come receivers which have corresponding analog inputs (I have my SACD player connected this way). You would get uncompressed audio with that kind of setup; but amps/receivers with the 5.1 analog inputs and BD players with those outputs are becoming rare as more people adopt HDMI.

The linear PCM is not necessarily compressed at the source. Some of the best sound I have heard is on linear PCM tracks. I just think you are not getting the full bandwith of the PCM sound with your receiver. Most BD players have the option to output sound as Bitstream or PCM. I set mine to Bitstream, and let my receiver decode the audio. Or, I could set the player to PCM and let the player decode the 5.1 audio before it sends it to the receiver. It sounds the same, but the receiver will not light up with DTS HD Master on the front panel.

Many thanks for the detailed explanation.

You know, I thought I was getting the full range audio via my Optical Output cable

One question:

Are there amplifiers with HDMI audio input jacks??

I know I can do this using my HDTV that has the HDMI connection, but what about amplifiers?

The whole process - the way the audio signals are processed - really sucks. Why do they make getting the original audio so darn difficult???

John,

P.S> I agree that linear PCM sound is not bad at all.

[Damfino]

The adoption of HDMI accomplishes two things:
1. All the HD audio and video signals are now carried by one cable. There is no longer a need for separate audio and video cables for devices that have HDMI (High Definition Media Interface).
2. All HDMI devices are also HDCP compliant. High-Bandwidth Digital Content Protection is a copy protection system designed to make it difficult or impossible to record the sognal that is being transmitted.

dave

[John Kim]

Dave,

But despite all the gimmicks they put in, I am pretty sure there are ways around, aren't there?

Using some software programs (e.g., Shrink) wouldn't it be possible to extract the uncompressed digital audio signal and burn it onto CDR??

I know some people do this for DVDs.

John,

[Damfino]

Yes, there are various programs to copy CDs, DVDs and even Blu-rays. The HDCP copy-protection scheme seems to only protect the signal from being recorded by a stand-alone recorder. The problems some amp/receivers have with some TVs and components (HDMI 'handshake' issues, etc) are probably caused by all the components checking each other to make sure they are all HDCP compliant.

dave

[Russell]

John, another thing to check would be the audio dynamic range setting in your Blu-ray player.  (I believe most DVD and BD players have such a setting.)  Of course you'd want to set it to 'uncompressed', 'full', or the equivalent.  BTW, this setting should only matter if you're using the analog outputs of your player into your receiver/amp; if you're outputting bitstream or PCM, you'll get the full-range signal.

I've extracted the PCM audio tracks of many of my music DVDs--even the copy-protected ones--to make very nice sounding CDs (for my own private use, of course).  (It's too difficult to do this with Blu-rays.)  I've come across a couple of DVDs with compressed audio tracks (it's very obvious when looking at the audio waveforms), so the compression you (sometimes) hear might be in the source.

Russell

[James Meckley]

May I suggest that there seems to be some confusion earlier in this thread between dynamic compression (the reduction in the difference between the loudest and the softest passages in a recording) and data compression (the reduction in the overall resolution of a recording for the purpose of reducing the size of its digital file)?

James

[John Kim]

May I suggest that there seems to be some confusion earlier in this thread between dynamic compression (the reduction in the difference between the loudest and the softest passages in a recording) and data compression (the reduction in the overall resolution of a recording for the purpose of reducing the size of its digital file)?

James

James,

I've been referring to only Dynamic Compression so far.

John,