Blu-ray vs. Blu-ray Pure Audio

[Horbus]

Couldn't find this topic anywhere else, if existent plse move there.
I`ve learned here in this forum that DVD-A as a format is different to music on DVD-Video which has lossy surronds but is more common nowadays for various reasons.
Does this also apply to Blu-ray Pure Audio vs. Blu-ray?
I noticed that some releases state "Pure Audio" on the disc case, like SDE releases and some don't like i.e. the Alan Parsons Project releases or the latest Van Morrison Moon Dance. Or is there no difference apart from the naming.
What do the experts here can say about it?
It's just of common interest to me.
Thanks for your input!

Horst

 

[dadregga]

DVDs typically didn't have enough space for lossless multichannel streams, so DVD-As were literally DVDs with a custom audio compression format that required special playback devices and support.

Plain old Blu-rays and all players supported 6ch 192/24 lossless out of the box, and had more than enough space, so no special "lossless audio" variant was required - Pure Audio was just a marketing term for a regular old standards-compliant Blu-ray with no video content.

 

[Horbus]

DVDs typically didn't have enough space for lossless multichannel streams, so DVD-As were literally DVDs with a custom audio compression format that required special playback devices and support.

Plain old Blu-rays and all players supported 6ch 192/24 lossless out of the box, and had more than enough space, so no special "lossless audio" variant was required - Pure Audio was just a marketing term for a regular old standards-compliant Blu-ray with no video content.

Thanks for your explanation. Regarding DVD-A someone here stated that it had something to do with the frmatting process itself and of course you need special device for playing it but space is not an issue, why should it be since both are DVD's.

 

[Horbus]

Well I looked it up again. The space issue referes not to the physical DVD itself but to DVD-V's not providing enough audio space for lossless because the main space is used/reserved for the video section, so far my understanding.

 

[AYanguas]

https://en.wikipedia.org/wiki/High_Fidelity_Pure_Audio

Pure Audio Blu-ray is a "normal" Blu-Ray that has a particular menu authored in it (marketing) that would enable playing the songs as a CD, just with the remote, without the need of a Video display to locate and navigate the menus.

Generally, a Pure Audio Blu-ray would contain only music tracks, so don't expect video such as documentaries, or clip videos, or the like. Although some of them may contain additional video in their menus

 

[mandrix]

Rolling back up to DVD-A....the DVD Audio structure is primarily an AUDIO_TS folder with lossless music. It can be lpcm or (preferred) mlp losslessy encoded.
I would say the main reason the VIDEO_TS folder, which was generally lossy AC3 and/or DTS, was originally so that someone that did not have a DVD-A capable DVD player could still play the music and/or video. This is accepted, but not required in the specs.
Video can also be linked from the lossless side to the lossy side.
There's more to it but most above my pay grade as the authoring app I use is not as full blown as the MEI/Sonic app.

 

[barfle]

Thanks for your explanation. Regarding DVD-A someone here stated that it had something to do with the frmatting process itself and of course you need special device for playing it but space is not an issue, why should it be since both are DVD's.

Much of the issue is bandwidth - how many bits per second the format can provide. Video compression on DVDs typically has two full frames per second, with the remainder being just what’s different than what was on the full frame. There’s a lot more to that process, but if you have a moving picture, it takes a LOT of bits per second.

DVD-As don’t have moving pictures, so they have more bandwidth for the audio. Even at that, the bandwidth is finite, and most DVD-As use what’s known as Meridian Lossless Packing to get it all to fit.

The two formats are inherently different, although they both use the same media and same wavelength laser, but they require different decoding processes, and most players don’t seem to have the DVD-A capability.

Blu-rays have vadtly more capacity (much smaller pits and more layers) and bandwidth than DVDs, so it’s not an issue.

 

[mandrix]

Blu Ray has vastly more capacity, for sure, but a double layer DVDA disc can hold quite a bit of music, since the VIDEO_TS folder is not required to be populated. But DVD-A is limited to 5.1.

 

[mandrix]

Much of the issue is bandwidth - how many bits per second the format can provide. Video compression on DVDs typically has two full frames per second, with the remainder being just what’s different than what was on the full frame. There’s a lot more to that process, but if you have a moving picture, it takes a LOT of bits per second.

DVD-As don’t have moving pictures, so they have more bandwidth for the audio. Even at that, the bandwidth is finite, and most DVD-As use what’s known as Meridian Lossless Packing to get it all to fit.

The two formats are inherently different, although they both use the same media and same wavelength laser, but they require different decoding processes, and most players don’t seem to have the DVD-A capability.

Blu-rays have vadtly more capacity (much smaller pits and more layers) and bandwidth than DVDs, so it’s not an issue.

One correction, Sir, DVD-A can have video. It's not in the lossless AUDIO_TS folder though, it has to be in the VIDEO_TS folder. I used to use DVDLab pro to author the video side...though I stopped years ago as it was of no use to me.

 

[mandrix]

Not to beat a dead horse, but coincidentally, my R.E.M. DVD-A Out Of Time disc "died" on me and I had to burn a copy from a backup .iso yesterday. As I was proofing it to make sure it burned correctly, I saw it has a documentary on it about making the album...which was linked (but not on) the lossless side menu.

 

[par4ken]

https://en.wikipedia.org/wiki/High_Fidelity_Pure_Audio

Pure Audio Blu-ray is a "normal" Blu-Ray that has a particular menu authored in it (marketing) that would enable playing the songs as a CD, just with the remote, without the need of a Video display to locate and navigate the menus.

Generally, a Pure Audio Blu-ray would contain only music tracks, so don't expect video such as documentaries, or clip videos, or the like. Although some of them may contain additional video in their menus

In addition players may have a "pure audio" button or setting to turn off the video as the audio is being played. You wouldn't need the video to navigate a pure audio disc but also the intent is to prevent any noise from the video circuits from affecting the audio in any way. Great idea, in practice I don't hear any difference. My Pioneer DVD player has such a setting as well.

 

[mandrix]

In addition players may have a "pure audio" button or setting to turn off the video as the audio is being played. You wouldn't need the video to navigate a pure audio disc but also the intent is to prevent any noise from the video circuits from affecting the audio in any way. Great idea, in practice I don't hear any difference. My Pioneer DVD player has such a setting as well.

Yes, and many if not most AVR's these days have a Pure Audio setting. Mine also has a "Direct Mode" which bypasses all EQ and "upmix" settings.

 

[barfle]

One correction, Sir, DVD-A can have video. It's not in the lossless AUDIO_TS folder though, it has to be in the VIDEO_TS folder. I used to use DVDLab pro to author the video side...though I stopped years ago as it was of no use to me.

True, there are DVD-A discs with video on them. I have several AIX recordings that have audio only parts as well as a video of the performance with lossy audio.

The question was about the difference betweem -A and -V, and this is not an adequate place for a full explanation.

 

[mandrix]

The question was about the difference betweem -A and -V, and this is not an adequate place for a full explanation.

How so?

 

[barfle]

How so?

It could fill a book.

 

[mandrix]

It could fill a book.

Yeah I guess. I was trying to not get too far out into the weeds, just explaining DVDA how it's set up.

 

[par4ken]

Yeah I guess. I was trying to not get too far out into the weeds, just explaining DVDA how it's set up.

I'm sure that it could be condensed into DVDA for Dummies!

 

[mandrix]

I'm sure that it could be condensed into DVDA for Dummies!

It was! lol.

 

[Horbus]

Thank you all for your replies and explanations! Now I'm getting a bit smarter!!

 

[SeeMoreDigital]

Video compression on DVDs typically has two full frames per second, with.....

For 'pure interlaced DVD's, the MPEG-2 video stream is encoded with two 'interlaced' fields per second. PAL DVD's have 50.00 fields per second, NTSC DVD have 59.940 fields per second.

For 'progressive' DVD's, the MPEG-2 video stream is encoded with one progressive frame per second. PAL DVD's have 25.000 'progressive' frame per second, often with interlaced flagging which can be removed using ReStream (v0.9.0). NTSC DVD's have 29.970 'flagged' frames per second, however when the 3:2 pull-down flagging is removed it reveals a progressive frame-rate of 23.976 frames per second.