iTunes Streaming Bitrate

[rWally]

I decided to do a little investigating to try and figure out what bitrate iTunes radio streams at. I closed all my applications except for iTunes and my resource monitor to track my network traffic.

As I was streaming a song the incoming network traffic for iTunes peaks around 400 kB/s but then falls off sharply several seconds into the song. It's obvious that iTunes creates a buffer for the rest of the song as the song begins and then plays from the buffer after the entire song has been downloaded.

From here i captured the total received bits during the playing of a single song and then calculated the kbps from there. I tested several different songs and most bit rates fell in the 280-300 kbps range. Now, not all of this data was strictly for the song being streamed since iTunes almost certainly has some overhead for simply running the service apart from song data.

It seems to me that iTunes Radio is likely streaming at the full 256 kbps AAC format that they sell their songs in.

FYI, I do have iTunes match so it's possible they reduce the quality for non match subscribers a la the Pandora premium service.

 

[Julien]

...It seems to me that iTunes Radio is likely streaming at the full 256 kbps AAC format that they sell their songs in.....

It looks like this is the case for WiFi. I have been using for a while in Mavericks and have used Activity Monitor to estimate about 10 to 15MB per song.

However in iOS over cell (LTE) is a whole different deal. I used iOS today for the first time and listened to several songs on WiFi and the quality was very good. I switched to LTE and the quality plummeted (using iPhone and UE 11 Pro's). I checked cell data and five songs only used about 12MB. This looks like about 96Kbps for LTE Radio. Very POOR quality.

Apple needs to offer a WiFi option to preload a Station with 256Kbps songs. I sent in an ER on this.

 

[rWally]

It looks like this is the case for WiFi. I have been using for a while in Mavericks and have used Activity Monitor to estimate about 10 to 15MB per song.

However in iOS over cell (LTE) is a whole different deal. I used iOS today for the first time and listened to several songs on WiFi and the quality was very good. I switched to LTE and the quality plummeted (using iPhone and UE 11 Pro's). I checked cell data and five songs only used about 12MB. This looks like about 96Kbps for LTE Radio. Very POOR quality.

Apple needs to offer a WiFi option to preload a Station with 256Kbps songs. I sent in an ER on this.

I haven't tested this in iOS yet but 96 Kbps would be a huge letdown. I wonder if that's a hard limit or if the bitrate can go up or down depending on signal strength/transfer speed.

 

[Julien]

I haven't tested this in iOS yet but 96 Kbps would be a huge letdown. I wonder if that's a hard limit or if the bitrate can go up or down depending on signal strength/transfer speed.

How much transfer speed do you need to get 256Kbps? Looks like I could get over 100 256Kbps songs simultaneously.

 

[Schtibbie]

It looks like this is the case for WiFi. I have been using for a while in Mavericks and have used Activity Monitor to estimate about 10 to 15MB per song.

However in iOS over cell (LTE) is a whole different deal. .

But what is the bitrate on iPhones using wifi? That's my scenario: at home. On wifi. Using iphone to airplay music over to an appletv that feeds out to a stereo system. I'd like to get better-than-pandora rates (pandora limits all ios streams to something like 96k even when on wifi).

 

[Julien]

But what is the bitrate on iPhones using wifi?...

WiFi, As stated I seem to get 256Kbps SQ on WiFI. It's cell that the quality goes WAY down and it's not related to my connections speeds.

 

[thelatinist]

Yeah, the quality is significantly poorer over cellular data and does not seem to be at all related to available bandwidth. This is frustrating for me as I've been using it in the car. Looks like this may be yet another reason to jailbreak.

 

[mpaquette]

I've been listening to iTunes radio over cellular on my iPad for the last couple of hours. It sounds fine at low volumes on my Jambox. I'm work so I keep the volume pretty low. Anyway, it seems to be using about 32 MB per hour. No idea how that translates to bitrate though.

 

[Julien]

...Anyway, it seems to be using about 32 MB per hour. No idea how that translates to bitrate though.

Someone check my math but that is less than 80Kbps (72.81Kbps average counting ads (if applicable) and in-between time) or POOR quality.

 

[bmcmurry]

Pandora's rate

But what is the bitrate on iPhones using wifi? That's my scenario: at home. On wifi. Using iphone to airplay music over to an appletv that feeds out to a stereo system. I'd like to get better-than-pandora rates (pandora limits all ios streams to something like 96k even when on wifi).

The last time I chatted with Pandora, they said that their bitrate was 128k for premium subscribers on non-mobile devices only. Otherwise, it's 64k.

 

[kalafalas]

I can confirm through data usage tests and bandwidth limiters that iTunes radio has three tiers of streaming quality for iOS, and it selects the appropriate one based on connection speed, and type.

80 kbps HE-AAC
192(?) kbps AAC
full 256 kbps AAC

It seems independent of of connection speed, if you are on any cellular it is *only* 80 kbps HE-AAC, (you can tell cause the restructured higher end of the sound kicks in a second or so after the song is loaded as you would expect from HE-AAC), I'm assuming this limitation is put in place to reduce weight on limited monthly data plans, and congestion of cell towers (I am on Verizon connected to LTE on a 5S averaging 20-30mbps down, on a 6gb share everything plan, idk if that makes a difference). Otherwise, if you are on Wi-Fi it adjusts based on connection speed (almost always 256, only dips down under very poor connections)

on OSX it gave me only 256, no matter what.

the only one I'm not positive about is 192, it is obvious there is a middle step when wifi bandwidth is constrained, but I cant confirm what bitrate it is, sometimes It's closer to 128 sometimes more like192+, it might be adaptive?

 

[JeremyLaurenson]

I can guarantee that iTunes radio is NOT 256k.

Simple test:


I am listening to radio right now, on a hardwaird 50MB connection.

Just listened to a song.
Clicked the but-it-now link.
Downloaded.
BIG difference.

My guess is 128... maybe 160.

 

[SanjeevRana]

I just did a quick test here in Singapore LTE and song downloaded at around 128 kbps and thats in a bad reception area ...