Podcast sample rate
richard22j at zoho.com
Tue Jul 18 07:57:49 PDT 2017
>Sent: Tuesday, July 18, 2017 15:18 I wrote
>My original question was why the BBC was using a 44.1kHz sampling rate for
>its podcasts (which are MP3) instead of standardising on 48kHz throughout.
>Dave Lambley thought the reason might be that the LAME encoder had been
>tuned for a 44.1kHz sample rate. There are certainly posts in
>hydrogenaudio which support that. One on the dbpoweramp forum said there
>were dire consequences of encoding a 48kHz sample rate as 320kbit/s MP3.
>All those posts are 10 to 14 years old, so I don't know if they still
>apply. There is no mention of it on the Wikipedia and Sourceforge LAME
The Sourceforge LAME page links to
HydrogenAudio's list of recommended LAME settings to produce best quality
encodes at several bitrates.
Under the heading 5.2 Resampling it says,
"When the input sample rate is greater than 48 kHz, LAME will resample it to
a maximum of 48 kHz (the maximum supported by MP3). In VBR modes 7 to 9.999,
and at CBR bitrates below 104 kbps, the input is resampled to 32000, 24000,
22050, 16000, 12000, 11025, or 8000, depending on the target quality level
"Since it is required when resampling, a filter is always applied to remove
frequencies above one-half the sample rate. The lowpass info above is
indicating whether any additional filtering is done. "
It would seem that there is no longer anything special about a 44.1kHz
sampling rate when encoding with LAME.
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