IPB

Welcome Guest ( Log In | Register )

The effects of musical genre upon ease/degree of compression, [split from “What music genres do you listen to?”, thread 96042]
IgorC
post Jul 17 2012, 05:06
Post #1





Group: Members
Posts: 1532
Joined: 3-January 05
From: ARG/RUS
Member No.: 18803



QUOTE (db1989 @ Jul 16 2012, 18:37) *
Is that suggesting that developers should make accommodations (of what nature?) for particular genres, rather than remaining objective and fair by sticking with universal principles of psychoacoustics? If so, I'm not sure how to feel about that!

Any audio codec has a "difficult" and "easy" genres to compress. The information about average collection (roughly speaking) helps to determine how much encoder can increase or decrease bitrate on some particular genres and still would hit desired bitrate on big variety of genres.

This post has been edited by IgorC: Jul 17 2012, 05:12
Go to the top of the page
+Quote Post
 
Start new topic
Replies
pawelq
post Jul 17 2012, 16:09
Post #2





Group: Members
Posts: 541
Joined: 20-December 05
From: Springfield, VA
Member No.: 26522



QUOTE (IgorC @ Jul 17 2012, 00:06) *
Any audio codec has a "difficult" and "easy" genres to compress.



You are oversimplifying. "Classical music" is often considered a single genre*, yet the acoustic structure and consequently the ease/difficulty of compression vary enormously. For example, a harpsichord piece will be typically hard to compress due to very fast attacks and wide frequency range. A mellow and quiet full-orchestra piece, will be much easier. Respective examples from my collection (all FLAC, same quality) are up to 983 kbps for a two-harpsichord piece by Bach vs. 523 kbps for a slow movement of Beethoven's symphony or 418 kbps for a slow movement of Mozart's piano concerto

*which is misleading in the first place, as you can probably find much more musical and/or textural variety within output of a single classical composer, or sometimes within one piece, let alone the "classical" genre spanning ~500 years of history of music, than in entire "genres" of popular music.


--------------------
Ceterum censeo, there should be an "%is_stop_after_current%".
Go to the top of the page
+Quote Post
pawelq
post Jul 20 2012, 17:16
Post #3





Group: Members
Posts: 541
Joined: 20-December 05
From: Springfield, VA
Member No.: 26522



Again, the purpose of that test was to address a specific assertion. Which was that rock/metal is harder to lossy-compress than classical because it contains more distortion, noise, non-harmonic and/or mistuned components. If this was true, then applying distortion/noise/mistuning etc to a harpsichord sample should make it more difficult to compress than the original harspichord sample. As much as the resulting bitrate at the same ogg quality setting is a measure of being easy vs. hard to compress, by small test showed the opposite. The modified sample was not supposed to be audibly indistinguishable form the original non-modified version, same as adding heavy distortion to a guitar is supposed to be audible.

This lead me to a conclusion that other factors than the amount of distortion and inharmonicty may be influence lossy compression.


--------------------
Ceterum censeo, there should be an "%is_stop_after_current%".
Go to the top of the page
+Quote Post

Posts in this topic


Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



RSS Lo-Fi Version Time is now: 24th July 2014 - 12:27