INTERACT FORUM

Please login or register.

Login with username, password and session length
Advanced search  
Pages: [1]   Go Down

Author Topic: Labeled bitrate for HE-AAC files  (Read 1160 times)

ksvane

  • World Citizen
  • ***
  • Posts: 124
Labeled bitrate for HE-AAC files
« on: August 07, 2011, 02:42:49 am »

The field [bitrate (labeled)] seems to show inaccurate values for HE-AAC files, in fact the displayed bitrate appears twice as big as the actual bitrate. Is this behaviour intentional? :-\ As I understand it, the sample rate of HE-AAC files is only half as big as the sample rate of the output (I think it's called spectral band replication?) I imagine this could be why the bitrate is somehow detected as twice its actual value (but I'm probably wrong).
Logged

Matt

  • Administrator
  • Citizen of the Universe
  • *****
  • Posts: 42053
  • Shoes gone again!
Re: Labeled bitrate for HE-AAC files
« Reply #1 on: August 08, 2011, 01:22:28 pm »

I don't seem to be able to reproduce this.

We're displaying the bitrate as found in the ESDS header of the MP4 container.

For the files I have, this value closely matches the bitrate you get by calculating manually (duration / bits).

Could you email a sample file to matt at jriver dot com?

Thanks.
Logged
Matt Ashland, JRiver Media Center

ksvane

  • World Citizen
  • ***
  • Posts: 124
Re: Labeled bitrate for HE-AAC files
« Reply #2 on: August 08, 2011, 02:02:11 pm »

done.
Logged

Matt

  • Administrator
  • Citizen of the Universe
  • *****
  • Posts: 42053
  • Shoes gone again!
Re: Labeled bitrate for HE-AAC files
« Reply #3 on: August 09, 2011, 08:49:23 am »

Thanks for the file.

It shows as "83" as the bitrate inside Media Center.  I think this is right.

If you take the file size divided by the duration:
2620438 bytes = 20964 kbit / 227 seconds = 92 kbit/sec

The numbers are a little different since the math above isn't subtracting the space in the file used for cover art, tags, etc.  So it should be a bit lower than 92, so 83 seems pretty reasonable.

Is this what you're seeing?  If not, does Update Library from Tags for the files help?
Logged
Matt Ashland, JRiver Media Center

ksvane

  • World Citizen
  • ***
  • Posts: 124
Re: Labeled bitrate for HE-AAC files
« Reply #4 on: August 09, 2011, 09:36:11 am »

Not quite what I'm seeing, no... here's a screenshot. The labeled bitrate stays roughly around 160 all the time.



Update library from tags makes no difference.
Logged

Matt

  • Administrator
  • Citizen of the Universe
  • *****
  • Posts: 42053
  • Shoes gone again!
Re: Labeled bitrate for HE-AAC files
« Reply #5 on: August 09, 2011, 10:51:55 am »

Ah, got it.

Coming soon:
Fixed: The bitrate displayed in the player area during playback could be double the actual bitrate for HE-AAC files.

Thanks.
Logged
Matt Ashland, JRiver Media Center

ksvane

  • World Citizen
  • ***
  • Posts: 124
Re: Labeled bitrate for HE-AAC files
« Reply #6 on: August 09, 2011, 11:38:52 am »

thanks! And sorry, perhaps I should have specified it was the text in the player area.
Logged
Pages: [1]   Go Up