IPB

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
Can AAC change sampling rate w/in file/stream? Do decoders support it?, [was “AAC Frequency transition” subt. “AAC” in General Audio/TOS #6]
poochi
post Aug 27 2013, 11:58
Post #1





Group: Banned
Posts: 11
Joined: 12-October 12
Member No.: 103802



AAC encoded data can come in many container formats . Like Mp4 ,adts etc., . In any of these are the sampling rates allowed to change inbetween a file ?If so are there any decoders which support it ?
Go to the top of the page
+Quote Post
saratoga
post Aug 27 2013, 17:32
Post #2





Group: Members
Posts: 5172
Joined: 2-September 02
Member No.: 3264



The sampling rate is fixed at encode time.

However for aac-he files a decoder can optionally downsample by 2 if it does not support he. This is because he files are actually encoded at half sample rate and then upsampled by the decoder to the original rate.
Go to the top of the page
+Quote Post
Rescator
post Aug 28 2013, 19:25
Post #3





Group: Members
Posts: 74
Joined: 13-January 09
From: Trondheim
Member No.: 65515



Also note that lossy encoders only encode as little as possible, so even if a sample rate was 192KHz, but there was only audio (or a lowpass filter) under 16000 Hz then that would be effectively the same as a sampling rate of 32KHz.


--------------------
"Normality exist in the minds of others, not mine!" - Rescator
Go to the top of the page
+Quote Post

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: 29th December 2014 - 06:05