It's interesting how Amazon stole the marketing language from video industry ("HD" and "Ultra HD") to promote and sell its high-res music. It's both clever (for their business) and stupid (insult to the brain and basic maths). They are distorting the meaning of high-res music and trying really hard to segment high-res music into two artificial categories by playing on subscribers' Ego and the sense of exclusive access to "something even better". An old trick.
"High Definition"
"High Definition"
label is not a high-resolution music at all. There is no such thing as "high definition" music. It's absurd. What they call "HD music" is simply a traditional lossless,
usual resolution FLAC file of CD-quality (16-bit x 44.1 kHz x 2 channels = up to 1,411 kbps of bitrate). They stream this category up to 850 kbps and call it "HD", without even exhausting the remaining 550 kbps of usual resolution 16-bit/44.1 music.
"Ultra HD"
Their "Ultra HD" label is, in reality, nothing more than high-res FLAC files with higher bit rate. Silly label, indeed. A classic high-res FLAC file could be 24-bits x 48 kbps x 2 channels = 2.3 Mbps or 4.6 Mbps for a file with 96 kHz
It is this bit rate that should be in "HD" category and not in "UHD"; simple audio math would suggest.
They stream this category in on average ~3.75 Mbps. On mobile phone with limited data packages, thought needs to be given. One hour a day of this category of music for one month would generate ~50 GB of data (3.75 Mbit/s x 60 sec x 60 min = 13.5 Gbit/h / 8 (bit into Byte) = ~1.7 GB/h x 30 days = 50.5 GB/month.
It turns out that "ultra HD" label in streaming music from Amazon is kind of fake news. In video environment, UHD at least has a real meaning of 3840x2160 resolution. In music environment, it's completely artificial category purely serving to up-segment and milk subscribers.
If they had really wanted to sell a proper Ultra HD musical equivalent to popular label used in 4K home theatre, they would have introduced DSD streaming, at least in stereo. Either way, this "UHD" is just yet another marketing stunt. It would cost them a lot of money to prepare DSD music library, set-up a new array of low-latency servers and convince consumers to take it for much higher price.
Minimal DSD64 file could take ~3 Mbps x 2 channels = ~6 Mbps of internet bandwidth. One hour of such pleasure would take: 6 Mbit/s x 60 sec x 60 min = 21.6 Gbit/h / 8 (bit into Byte) = 2.7GB/h. One hour a day of DSD music for one month would generate 81 GB of data. While hypothetical streaming of basic DSD over home network would be fine for unlimited data plans, it would be a no-go on vast majority of mobile phone plans and millions of home plans, as this broadband map below suggests. So, we are faw away from DSD streaming on more commercial scale, similarly to 8K in video environment.
The worst connections in the country.
www.theverge.com
They also have issues with so called remastered albulms. Investigating the repository of their music more deeply brings a mixed bag of results. It's difficult to identify whether some remastered albums are really what they say it is. Try to listen original and remastered versions of, say Nirvana's Nevermind or similar, to see whether there is a significant difference and if the remastering origin could be identified.
It's nice to explore a lot of music on offer, I do it daily, but let's keep our heads on shoulders in terms of audio maths and aggressive marketing of meaningless labels for music. Any thoughts?
