Akira is 192khz, why not other movies?

[jkwest]

Originally Posted by saprano

He has nothing to do with the remaster

you wanna rethink that? He has already stated that he helped....


edit....whoops..my bad..misread this post..

Originally Posted by Jeff Kleist

I wish

I didn't take part in it, I only got to talk to the guy who did it, though I would have been happy to help if they'd asked

RKish, very odd we're running the same player, and I haven't had a problem with it at all. Firmware's up to date right?

[Jeff Kleist]

I do work with a bunch of Japanese music lables, but I've never work-worked with Bandai or any of the other anime companies in an official capacity. Hopefully I can do more stories in the future on big restorations that Bandai and/or other companies there do. I've passed some of the reaction back to Tatei-san so that he can show it to the team.

Oh and uncredited thanks go to my friend, ironically named Akira (it's a common name in Japan) who helped with interpretation

[BergerForLife]

As an audio engineer with a full time job at a studio I would like to clear a couple things up.

1) The sample rate (in this case 192kHz) does actually relate to the highest audible frequency. The nyquist theorem states that the highest frequency in a recording is half the sample rate. So 192/2 = 96kHz would be the highest frequency. As compared to 48/2 = 24kHz being the highest frequency.

2) So at a sample rate of 48 kHz yes it does cover "the human hearing range". Recently some research has said we can actually hear up to 20kHz. So as of right now there is no accurate proof as to what the average human can hear. However, I'm not going to argue that.

3) Regardless of human hearing range, would a higher sample rate still affect the sound? Absolutely yes. There are a few reasons why, and "Aliasing" is one I will explain. When a sound is made it has a certain frequency, and with that frequency comes overtones. Overtones are twice the fundamental frequency. So if an instrument plays 8kHz, that overtone is 16kHz, and the overtone of that is 32kHz. At 32kHz we have gone over the nyquist number of the sample rate 48kHz (24kHz), so the recording will do what is known as aliasing. In this example 32kHz went over the nyquist number by 8kHz (32-24). Therefore the audio will "Alias" 8kHz under the nyquist number. (24-8=16) And we will hear a frequency at 16kHz when it should have been at 32kHz.

Therefore, without recording at twice the frequency of not only the fundamental frequencies, but the overtones too, we hear frequencies in the audio that were never recorded. High sampling rates aren't there for no reason, and we are always told to record at the highest sampling rate possible. Aliasing is no fun. Hope this was easy enough to understand.

[phantompwr]

The increased sampling frequency would prevent aliasing, but all good converters already have a way to prevent that without saving things at 192kHz. The converter samples the incoming audio at frequencies a lot higher even than 192 kHz, and then once the audio is digital they can use a digital low-pass filter to cut off those higher frequencies that could be mistakenly converted to a lower, audible frequency. Then the audio can be resampled to 48 kHz without worrying about aliasing.

[HDJK]

Originally Posted by ToEhrIsHuman

yes...let's please end this confusion once and for all. 192kHz sampling means 192,000 "time slices" or samples of the waveform, whereas typical redbook CDs are sampled at 44.1kHz and typical BD audio at 48kHz (or 44,100 and 48,000 times per second respectively). This means for every one sample at 48kHz you are getting four samples at 192kHz, which would be more data per second and a more accurate representation of the original analog waveform. The stream also takes up roughly 4 times as much space on the disc too - less with lossless compression.

These numbers have absolutely nothing to do with audible frequencies, i.e. the pitch of sound (highs and lows).

I may rent this disc just to hear the audio.

let's please end this confusion once and for all: The bolded part is NOT true!

A quote from on here I think (I can't remember who wrote it, but it is correct nevertheless):

With PCM, samples do not describe the analog shape.
It's the popular pr explanation but it's not how PCM works in principle.

Each puls causes a 'ringing effect' in the steep filter used to reconstruct the analog signal. The ringing effects of all the sample pulses are in effect summed in the filter (convulated) resulting in the analog output signal.

The accuracy of the reconstructed signal relies on the bith depth mostly.

Doubling the sample rate gives twice the frequency range.
Another effect is that the quantization noise floor drops slightly (~1dB) as well because the errors and noise are spread across a larger frequency range.

an 16 bit 96ks PCM signal has the equivalent noise and distortion spectrum of an 17bit 48ks PCM signal.

For improving accuracy adding bits is far more efficient than doubling the sample rate.

[HDJK]

Originally Posted by phantompwr

The increased sampling frequency would prevent aliasing, but all good converters already have a way to prevent that without saving things at 192kHz. The converter samples the incoming audio at frequencies a lot higher even than 192 kHz, and then once the audio is digital they can use a digital low-pass filter to cut off those higher frequencies that could be mistakenly converted to a lower, audible frequency. Then the audio can be resampled to 48 kHz without worrying about aliasing.

Correct. And with 96kHz the LPF is far away from the audible range. No need really for 192kHz in that regard.

[BergerForLife]

Thing is a lot of times you convert after you mix. Which means you'd be mixing with frequencies that shouldn't be there. You always want to get the best sound going in, so you don't have to mess with it later. So like I said when you can It's a must to record at a higher sampling rate, a lot less problems later on.

[phantompwr]

Everything I described in the last post should be built in to your analog to digital converter, you wouldn't even know it was happening.

[J0NESI]

all i got to say is i watch movies around -22.0dB and iam watchin akira right now at -34.5, when watch i it at-22.0dB it is super loud. Louder than anything else i have. i cant get over it.

[saprano]

Does akira still come with that booklet explaining the audio?

[Red Hood]

Originally Posted by saprano

Does akira still come with that booklet explaining the audio?

No, You will have to find one via trading forum, ebay or amazon marketplace.

[Louisville Slugger]

192 kHz sampling rate * 24 bits of resolution * 6 channels equals 27.6 Mbps/sec audio bitrate.

Let's assume an average movie is 1 hour and 45 minutes.

1 hour and 45 minutes equals 6,300 seconds.

6,300 seconds * 27.6 Mbps/sec equals 173,880 megabits equals 21.22 GB.

50 GB - 21.22 GB equals 28.78 GB left for video, alternate languages, extras, etc.

28.78 GB equals 235,765.76 megabits divided by 6,300 seconds equals 37.4 Mbps/sec video bitrate.

Wonder if it would be possible to just have the movie at an average of 37.4 Mbps/sec and a 192/24 6 channel uncompressed PCM track.

Not sure if I did this right, but having such a high quality audio track sucks up space. I guess a TrueHD 192/24 track would be more efficient than a 192/24 PCM track, but space would end up becoming an issue either way. Extras would have to be put on another disc and that would cost more. Also what about all those different language audio tracks? And if the movie is over 1 hour and 45 minutes fugetaboutit!

I have to agree about the quality though. After hearing TrondheimSolistene: Divertimenti's LPCM 192kHz/24bit 5.1 audio track you want everything to sound that good,

[odin24]

The actual 192/24 track on Akira consumes approx 15GB of disk space, this is not based on a calculation either. What is even more impressive is the fact that the embedded core AC3 track is only 2 channels @ 192kb/s.

[Jeff Kleist]

Not sure if I did this right, but having such a high quality audio track sucks up space. I guess a TrueHD 192/24 track would be more efficient than a 192/24 PCM track, but space would end up becoming an issue either way. Extras would have to be put on another disc and that would cost more. Also what about all those different language audio tracks? And if the movie is over 1 hour and 45 minutes fugetaboutit!

The disc producer actually wanted to do PCM, but unfortunately that's 24mbps if memory serves, which blows out the max audio bitrate of the Blu-ray spec As it was Dolby worked hand and hand with Bandai to fit that, the 48/16 dub track and the DD tracks in the allotted space. It was a very tight fit and required a lot of massaging.

[Rob J in WNY]

Very interesting thread!

I am curious. Does anyone know if the 192KHz/24-bit audio is present on BOTH the Japanese Dolby TrueHD and English Dolby TrueHD tracks?

[aramis109]

Originally Posted by Rob J in WNY

Very interesting thread!

I am curious. Does anyone know if the 192KHz/24-bit audio is present on BOTH the Japanese Dolby TrueHD and English Dolby TrueHD tracks?

Japanese only. I just finished watching the BD tonight. Managed to snag a used one in stellar shape that even included the booklet describing the audio. Interesting read. To say the least, while I don't know if I buy into the whole hypersonic deal, I can honestly say that the audio track is a true marvel, and it's amazing. I'm glad I finally updated my DVD version with this. The audio is amazing.

Jeff, what's weird is that there's an English TrueHD track, the awesome Japanese TrueHD track, and then another PCM track. Seems like no point considering the unparalleled track's presence on the disc.

[Rob J in WNY]

Originally Posted by aramis109

Japanese only.

Thanks, Aramis. That's what I thought I had read online before, but I knew someone here would have the definitive answer. I would totally enjoy it in the original Japanese dialog, and just read subtitles to follow the movie, and enjoy its depth of 192KHz sound.

Akira is on my short list of titles I would like to own, but I can wait for it to come in a lower price, unless, like you, I can find it used (and hopefully get the info booklet on the "hypersonic" theory). It would be a nice find that way.

[jd213]

The PCM should be the original theatrical mix.

[42041]

Save the bitrate for something that makes a difference...

[aramis109]

Originally Posted by Rob J in WNY

Thanks, Aramis. That's what I thought I had read online before, but I knew someone here would have the definitive answer. I would totally enjoy it in the original Japanese dialog, and just read subtitles to follow the movie, and enjoy its depth of 192KHz sound.

Akira is on my short list of titles I would like to own, but I can wait for it to come in a lower price, unless, like you, I can find it used (and hopefully get the info booklet on the "hypersonic" theory). It would be a nice find that way.

Keep an eye on gohastings.com. That's where I got mine for about $14, and I was shocked to get the booklet.

Originally Posted by 42041

Save the bitrate for something that makes a difference...

Assuming you mean the 192khz 24bit TrueHD, it definitely does make a difference. Have you listened to it? If not, you have no leg to stand on. It's truly a marvel.