Bluray audio question.

[admin_exported]

Hi,

Just reading throught the bluray player reviews, and WHF often talking about the players sonic ability. Does this apply to when audio is bitstreamed to the receiver?

I would think that every player is equal when bitstreaming. And PQ is the most important aspect to look for in a player.

Your thoughts are appreciated.

Thank you

 

[aliEnRIK]

Whether picture quality is the most important or not is upto each individual

Bitstreaming - jitter can definitely have an effect on quality

 

[def lugs]

I agree with RiK, the quality depends on how accurately the player can retrieve and process the information without error. A drive that is rated to achieve a certain data transfer rate has to achieve the minimum without errors. All players are built to a certain cost and tolerence some players will be closer to the minimum specification than others, the signal can also be subject to more interference on its path through the player.

I prefer the audio to be better than the picture, but I am less sensitve to whether 'flesh tones look natural' or not as long as the image moves smoothly, I am happy.

 

[bigboss]

....although WHF does not specify bitstreaming. One can only assume that they're talking about the player decoding audio. If a player doesn't decode audio well, it doesn't mean that it doesn't bitstream well either. It's another matter that I don't think that jitter, if any, can cause perceivable difference.

 

[Anonymous]

hdmi cables only transport digital data, so i don't see how a blu-ray player can decode digital audio data and send it to a receiver via hdmi?

unless it's output via a players multi channel outs (should a player have them) to said receiver, then surely the audio data would have to be decoded, or at least re-decoded by the receiver?

which would make the quality of the dac in the bdp irrelevant?

or is it early on a sunday and i'm completely missing something obvious

 

[DandyCobalt]

It would seem logical that, as far as audio goes, then a blu-ray player should work to the same principles as a standard CD Player - it performs first as a "transport", from which digital data (via coaxial/optical or HDMI) is sent to the pre-amplifier, a/v receiver, or tv; secondly, it contains digital-analogue conversion capabilities (DACs) which convert the digital signal collected by the transport within the machine to analogue, which can then be sent out in analogue to the amplifier or a/v receiver.

CD Players differ in quality in both these respects (transport and DAC) and therefore Blu-ray players should too.

I've just bought the Cambridge Audio BD751, and still have my previous 650 for the next couple of days until it is sold (can't give the link...house rules) and today I will try to find time to do a head-to-head of the comparative stereo and multi-channel (bitstream and LPCM) capabilities, with my own system.

I'm quite intrigued, because in my system chain I have the Blu-ray player, the Pioneer LX53, and (for stereo) a higher-end dac-loaded Cyrus pre-amp - all of these are capable of doing the very important DAC component of the sound.

 

[Anonymous]

Thanks guys,

There are so many conflicting views out there, its hard to know whats true and faulse. I thought the higher end players include better DVD upscalling chips, multi disc formats, better analoge DAC etc. Hence the higher price. And that there would be very little difference between cheap players and high end players with bluray dics.

In regards to the the CA BDP 650, WHF say "not quite the best picture 400 can buy" So, what is the best picture at this price range?

 

[Anonymous]

hdmi cables only transport digital data, so i don't see how a blu-ray player can decode digital audio data and send it to a receiver via hdmi?

unless it's output via a players multi channel outs (should a player have them) to said receiver, then surely the audio data would have to be decoded, or at least re-decoded by the receiver?

which would make the quality of the dac in the bdp irrelevant?

or is it early on a sunday and i'm completely missing something obvious

This cannot be right. The old FAT PS3 will not bitstream HD audio and does its own onboard decoding, video and audio sent via HDMI to my receiver.

 

[Anonymous]

Both uncoded digital data and decoded digital data travel down an HDMI, whether the player carries out the decoding or not they are both in LPCM form. All the decoding process achieves isto ensure the correct audio information goes into the correct channels.

 

[Anonymous]

hdmi cables only transport digital data, so i don't see how a blu-ray player can decode digital audio data and send it to a receiver via hdmi?

unless it's output via a players multi channel outs (should a player have them) to said receiver, then surely the audio data would have to be decoded, or at least re-decoded by the receiver?

which would make the quality of the dac in the bdp irrelevant?

or is it early on a sunday and i'm completely missing something obvious

This cannot be right. The old FAT PS3 will not bitstream HD audio and does its own onboard decoding, video and audio sent via HDMI to my receiver.

hdmi only transports digital data, so the receiver would have to be doing the (audio at least) decoding..

 

[Anonymous]

hdmi cables only transport digital data, so i don't see how a blu-ray player can decode digital audio data and send it to a receiver via hdmi?

unless it's output via a players multi channel outs (should a player have them) to said receiver, then surely the audio data would have to be decoded, or at least re-decoded by the receiver?

which would make the quality of the dac in the bdp irrelevant?

or is it early on a sunday and i'm completely missing something obvious

This cannot be right. The old FAT PS3 will not bitstream HD audio and does its own onboard decoding, video and audio sent via HDMI to my receiver.

It's simple, really. The audio conversion process from BR bitstream to analog audio has two steps: firstly, decode the audio bitstream (mostly in Dolby AC3, DTS HD formats) into LPCM (multichannel) audio, then convert the LPCM to analog through a DAC.

So a player may:
- send the raw bitstream to the receiver, and the receiver will do both the decoding and the DA conversion (not all receivers understand all bitstreams)
- decode the bitstream, and let the receiver do the DA conversion (all receivers must understand LPCM)
- decode and do the DA conversion, send the sound through the analog outs, and the receiver only does the amplification

In the first two scenarios, the DAC in the player does not matter. In the latter, the digital audio processing of the receiver doesn't matter. I assume that when WHF discusses the audio capabilities of a BDP, that they're using the third option. It would be really disingenuous to do otherwise.

 

[Anonymous]

hdmi cables only transport digital data, so i don't see how a blu-ray player can decode digital audio data and send it to a receiver via hdmi?

unless it's output via a players multi channel outs (should a player have them) to said receiver, then surely the audio data would have to be decoded, or at least re-decoded by the receiver?

which would make the quality of the dac in the bdp irrelevant?

or is it early on a sunday and i'm completely missing something obvious

This cannot be right. The old FAT PS3 will not bitstream HD audio and does its own onboard decoding, video and audio sent via HDMI to my receiver.

hdmi only transports digital data, so the receiver would have to be doing the (audio at least) decoding..

No, the old ps3 does the de-coding to (LPCM) I.e. Less information, therefore less bandwidth (which allows it to be sent via old HDMI protocols) and the AVR carries out the digital to analogue conversion in this instance to then allow amplification.

 

[Anonymous]

hdmi cables only transport digital data, so i don't see how a blu-ray player can decode digital audio data and send it to a receiver via hdmi?

unless it's output via a players multi channel outs (should a player have them) to said receiver, then surely the audio data would have to be decoded, or at least re-decoded by the receiver?

which would make the quality of the dac in the bdp irrelevant?

or is it early on a sunday and i'm completely missing something obvious

This cannot be right. The old FAT PS3 will not bitstream HD audio and does its own onboard decoding, video and audio sent via HDMI to my receiver.

hdmi only transports digital data, so the receiver would have to be doing the (audio at least) decoding..

No, the old ps3 does the de-coding to (LPCM) I.e. Less information, therefore less bandwidth (which allows it to be sent via old HDMI protocols) and the AVR carries out the digital to analogue conversion in this instance to then allow amplification.

ah ok mark, but in that instance, as has been mentioned, the dac in the bdp is not used, so aren't the audio capabilities of a bdp only relevant if it has multi channel outs?

 

[Andrew Everard]

ah ok mark, but in that instance, as has been mentioned, the dac in the bdp is not used, so aren't the audio capabilities of a bdp only relevant if it has multi channel outs?

No, because it can also depend on how well it decodes the HD soundtrack to LPCM.

 

[Anonymous]

ah ok mark, but in that instance, as has been mentioned, the dac in the bdp is not used, so aren't the audio capabilities of a bdp only relevant if it has multi channel outs?

No, because it can also depend on how well it decodes the HD soundtrack to LPCM.

you mean there could be errors in that conversion process?

 

[Anonymous]

ah ok mark, but in that instance, as has been mentioned, the dac in the bdp is not used, so aren't the audio capabilities of a bdp only relevant if it has multi channel outs?

No, because it can also depend on how well it decodes the HD soundtrack to LPCM.

you mean there could be errors in that conversion process?

I would say it depends on the decoders accuracy of interpreting the sound track to correctly place each effect.s etc.

 

[Andrew Everard]

you mean there could be errors in that conversion process?

There is always the possibility of errors in any decompression or decoding process: it's more a matter of how well they're corrected.

But to answer the main point, testing is carried out with every version of audio output on players, from HDMI (in direct and LPCM versions), through S/PDIF and stereo/multichannel analogue where provided.