Netflix upping sound quality

[stunta]

Not lossless, but I'll take anything I can get.

https://www.engadget.com/2019/05/01...gn=homepage&utm_medium=internal&utm_source=dl

 

[Blumlein 88]

I wonder if they've already done this for some of their movies. I've had the Dolby Digital Plus illuminate on quite a few Netflix movies. I use a Roku Streaming stick Plus. Maybe they've just now gotten it so it is on all of their content.

From that article:
Netflix boosted the bitrate for the show, and since then, it says it's been working to roll out similar improvements more broadly.

 

[vert]

I'm in Switzerland, was subscribed to Netflix for a while. I cancelled the subscription though as their catalogue was so limited - I've heard it's smaller here than in other countries. Things I loved about Netflix were the image and sound quality, they were definitely superior to movies rented say on Swisscom TV, the largest local provider. Swisscom are the main owners of the network, have made huge investments into state-of-the-art fiber optic infrastructures, yet seem unable to make the most of their own network for their customers.

 

[mansr]

I wonder if they've already done this for some of their movies. I've had the Dolby Digital Plus illuminate on quite a few Netflix movies.

They've used DD+ for all surround sound for quite some years. The change they're making now is merely an increase in bit rate.

 

[M00ndancer]

And going for 768 instead of 640 isn't that much increase. However, I've been listening to DD 5.1 and DTS 5.1 for years and that extra bandwidth makes a difference (also having the ability to move the bandwidth around where it's most needed is a big bonus). DD+ is better format to begin with.
So I'm like the improvement even if it might not be that of a big difference.

 

[Willem]

I have only one additional request: decent movies rather than this commercial drivel.

 

[marksquared]

Great news. If this trend continues I can finally cancel my DVD.com subscription.

 

[Sal1950]

I have only one additional request: decent movies rather than this commercial drivel.

I struggle every month when I see the bill not to cancel. It's been quite a while since I felt I was getting value for my money when it came to the offerings I viewed each month. They add more and move new internally made garbage that gets worse and worse with time.

 

[restorer-john]

I really don't know what I am getting on Netflix, but it sounds perfectly good to us for movies. It's HDMI from my HTPC into the Samsung panel, then SPDIF optical into my Rotel D/A at 16/48KHz. All DD is sent out as PCM from our panel to be compatible with my older D/A converter. Not interested in multichannel- did it to death back in the day.

 

[flipflop]

According to Netflix, its "high-quality sound feature is not lossless, but it is perceptually transparent." So while the audio will be compressed

"Lossless" and "compressed" are not mutually exclusive. A FLAC recording can be either compressed or uncompressed. Both will be lossless.

Through internal tests, Netflix determined that, for Dolby Digital Plus, 640 kbps is the point at which additional quality is imperceivable, and for Dolby Atmos, Netflix says the threshold is 768 kbps.

I strongly doubt bitrates that high are necessary for transparency. The fact that the internal report is top secret doesn't alleviate my suspicion.

 

[M00ndancer]

I strongly doubt bitrates that high are necessary for transparency. The fact that the internal report is top secret doesn't alleviate my suspicion.

640 is not enough and 768 is not either, we are talking 6 or 8 channels that share the bandwidth. Those 768kbit are divided between 6? channels. 768/6 = 128kbit/ channel (Not sure about the specs) and Dolby TrueHD is 8 channels with up to 18Mbit total bandwidth.

From Wikipedia:

Dolby Digital Plus

, also known as Enhanced AC-3 (and commonly abbreviated as DD+ or E-AC-3, or EC-3) is a digital audio compression scheme developed by Dolby Labs for transport and storage of multi-channel digital audio. It is a successor to Dolby Digital (AC-3), also developed by Dolby, and has a number of improvements including support for a wider range of data rates (32 Kbit/s to 6144 Kbit/s), increased channel count and multi-program support (via substreams), and additional tools (algorithms) for representing compressed data and counteracting artifacts. While Dolby Digital (AC-3) supports up to five full-bandwidth audio channels at a maximum bitrate of 640 Kbit/s, E-AC-3 supports up to 15 full-bandwidth audio channels at a maximum bitrate of 6.144 Mbit/s.

 

[Soniclife]

640 is not enough and 768 in not either, we are talking 6 or 8 channels that share the bandwidth. Those 768kbit are divided between 6? channels. 768/6 = 128kbit/ channel (Not sure about the specs) and Dolby TrueHD is 8 channels with up to 18Mbit total bandwidth.

Has anyone done multichannel blind tests? It should be as easy as doing it with 2 channel, with the right software, and without pictures, if you have a surround sound system. I'd be very interested to know if the thresholds change if you are also actively watching the picture.

I'm very tempted to believe them if there is no evidence to the contrary.

 

[SMc]

Netflix is ahead of Amazon where compression artifacts are clearly audible in undemanding speech sounds (for instance in Bosch).

 

[JohnBooty]

640 is not enough and 768 is not either, we are talking 6 or 8 channels that share the bandwidth. Those 768kbit are divided between 6? channels. 768/6 = 128kbit/ channel

That's potentially more than enough, right?

Yes, it's divided by 6 channels. But think about what's actually coming through those channels at any given moment.

• Center channel: dialogue and primary SFX
• Left and right channels: music, offscreen SFX. (however, music is not usually playing at the same time as dialogue, at least not loud/complex music)
• Surround/rear channels: very occasional SFX, light environmental SFX
• .1 bass channel: technically a full-range channel IIRC but in practice we know it's always low bandwidth low frequency boomy noises

If your video stream was blasting loud/complex full-range sound (read: music) through all six channels simultaneously? We'd use up that 768kbps in a hurry. In reality, that happens approximately never. You really never have heavy amounts of information playing through more than two or three channels at a time. As a bonus, dialogue compresses rather efficiently compared to music.

One reason sound designers tend to underuse those surround/rear channels is because they're rarely present and when they are, they're rarely set up correctly. Theoretically, a sound designer could have crucial dialogue emanating from one of those channels. In reality, a lot of people aren't ever going to hear it.

I have only one additional request: decent movies rather than this commercial drivel.

Yeah. Netflix's original programming to me is sometimes decent but a lot of the time it sort of feels like they're just trying to shovel as much algorithm-designed content as possible onto that thing.

Once (if?) my work schedule eases up I'm looking foward to trying out: https://www.criterionchannel.com/

 

[Sal1950]

Amazing how some here are more than willing to throw the data rate for multich on the sacrificial alter of "Good Enough".
No thanks, I don't think you'd be happy with that attitude for your 2 channel. We can do so much better
Here's hoping BD and 4K BD with lossless Dolby, DTS, and Auro survive long enough for folks to come to their senses.

 

[Willem]

The Criterionchannel does indeed seem interesting, and the only thing I could be persuaded to pay for: proper art films. Sadly, it looks as if the dialogue is not in the original language, but maybe there is a language setting somewhere.

 

[M00ndancer]

I'm very tempted to believe them if there is no evidence to the contrary.

If Netflix states that there is a significant difference between 640 and 768 then you will want a lot more bandwidth than 768. But the most glaring thing about Netflix and every other streaming service is the lack of Mbit for the picture. Sound more or less takes second stage in that regard.

 

[Soniclife]

If Netflix states that there is a significant difference between 640 and 768 then you will want a lot more bandwidth than 768.

That's not what the article says, it does not state what the previous rate was, anyone know?

 

[flipflop]

That's not what the article says, it does not state what the previous rate was, anyone know?

Based on the Netflix rips I have access to it's 384 kbps, AC-3, 5.1ch.

 

[DuxServit]

Here is a link to the Netflix technical blog. Interesting how they do “adaptive streaming”:

https://media.netflix.com/en/company-blog/bringing-studio-quality-sound-to-netflix
https://medium.com/netflix-techblog...th-high-quality-audio-at-netflix-eaa0b6145f32

...
Our high-quality sound feature is not lossless, but it is perceptually transparent. That means that while the audio is compressed, it is indistinguishable from the original source. Based on internal listening tests, listening test results provided by Dolby, and scientific studies, we determined that for Dolby Digital Plus at and above 640 kbps, the audio coding quality is perceptually transparent. Beyond that, we would be sending you files that have a higher bitrate (and take up more bandwidth) without bringing any additional value to the listening experience.
...
By using adaptive streaming for audio, we allow audio quality to adjust during playback to bandwidth capabilities, just like we do for video.
...
By using our listening tests and scientific data to choose an optimal “transparent” bitrate, and designing an adaptive audio algorithm that could serve it based on network conditions, we’ve been able to enable this feature on a wide variety of devices with different CPU, network and memory profiles: the vast majority of our members using 5.1 should be able to enjoy new high-quality audio.
...