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MP3 / Re: Low bitrate MP3 (+ unsupported bitrates)
Last post by Kraeved -Quote
MPEG-1 Audio Layer III: 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320 kbps
MPEG-2 Audio Layer III: 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160 kbps
MPEG-2.5 Audio Layer III: 8, 16, 24, 32, 40, 48, 56 kbps
These are the bitrates for MP3 CBR mode. There is no 12 kbps among them. Thus, to get 12 kbps file, which can be played back on a wide range of audio equipment, you have no choice but to use VBR mode (or ABR as a variation of it) so that some of the data is compressed at a lower bitrate and some of the data is compressed at a higher bitrate, producing the output that is as close as possible to the bitrate you specified.
RTFM #2
Quote
If not specified, LAME may sometimes resample automatically when faced with extreme compression conditions (like encoding a 44.1 kHz input file at 32 kbps). To disable this automatic resampling, you have to use --resample to set the output samplerate equal to the input samplerate. In that case, LAME will not perform any extra computations.
gxlame.exe --abr 12 -h --lowpass 3500 --resample 11025 in.wav out.mp3
Code: [Select]
GXLame-t5
CPU features: MMX (ASM used), SSE (ASM used), SSE2
Using polyphase lowpass filter, transition band: 3423 Hz - 3556 Hz
Encoding history.wav to history.mp3
Encoding as 11.025 kHz single-ch MPEG-2.5 Layer III (14.7x) average 12 kbps qval=0
Frame | CPU time/estim | REAL time/estim | play/CPU | ETA
324/324 (100%)| 0:00/ 0:00| 0:00/ 0:00| 60.240x| 0:00
8 [170] *********************************************************************
16 [137] ********************************************************
24 [ 15] *******
32 [ 2] *
40 [ 0]
48 [ 0]
56 [ 0]
64 [ 0]
-------------------------------------------------------------------------------
kbps mono % long switch short %
12.3 100.0 90.1 5.6 4.3
Writing LAME Tag...done
ReplayGain: -0.2dB