INTERACT FORUM

Please login or register.

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

Author Topic: "Bit depth" and mp3 / m4a files  (Read 2574 times)

jacobacci

  • Galactic Citizen
  • ****
  • Posts: 256
"Bit depth" and mp3 / m4a files
« on: June 02, 2015, 08:19:19 am »

mp3 or aac encoded files do not have a fixed bit depth. Apparently the encoders use floating point arithmetic and the result can be decoded to any desired level of accuracy or bit depth. JRiver seems to automatically send the maximum accuracy / bit depth that the output device can handle.

If I use the [Bid Depth] parameter in the Main status window, it reports back a depth of 16bit. Would it not be more appropriate to report back "undef" or "-" or similar to indicate that the file being played does not have a defined bit depth. The actual bit depth going to the audio device seems to be reported correctly in the Audio Path window.

Logged

Hendrik

  • Administrator
  • Citizen of the Universe
  • *****
  • Posts: 10944
Re: "Bit depth" and mp3 / m4a files
« Reply #1 on: June 02, 2015, 08:58:54 am »

Wrong. The bit depth is fixed at 16 bit. What is variable is the sample rate (bit rate).

Actually thats wrong. Bitdepth of aac or mp3 is not clearly defined as jacobacci suggests, as they are lossy formats. It depends on the decoder which bitdepth is output in the end, and for maximum precision they should be decoded to 32-bit floating point.
But MC has to fill the bitdepth field with something, so not to cause confusion and make people think those are High-Definition audio files or something, MP3 usually gets 16 assigned there.
Logged
~ nevcairiel
~ Author of LAV Filters
Pages: [1]   Go Up