Changes between Version 12 and Version 13 of Encode/MP3


Ignore:
Timestamp:
Jun 11, 2014, 6:01:14 AM (5 years ago)
Author:
Timothy_Gu
Comment:

Misc. fixes

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  • Encode/MP3

    v12 v13  
    33This page describes how to use the external libmp3lame encoding library within `ffmpeg` to create MP3 audio files (`ffmpeg` has no native MP3 encoder).  See also [[GuidelinesHighQualityAudio|other codecs]] you could use, and [[Encode/AAC|FFmpeg AAC Encoding Guide]] for background on FFmpeg audio encoding in general.
    44
    5 = VBR Encoding =
     5== VBR Encoding ==
    66
    77Example to encode VBR MP3 audio with `ffmpeg` using the libmp3lame library:
     
    1212Control quality with `-qscale:a` (or the alias `-q:a`). Values are encoder specific, so for libmp3lame the range is 0-9 where a lower value is a higher quality. 0-3 will normally produce transparent results, 4 (default) should be close to perceptual transparency, and 6 produces an "acceptable" quality. The option `-qscale:a` is mapped to the `-V` option in the standalone `lame` command-line interface tool.
    1313
    14 ||||||= '''LAME Bitrate Overview''' =||
    15 || `lame` option || Kbit/s || Bitrate range kbit/s || `ffmpeg` option
     14||||||||= '''LAME Bitrate Overview''' =||
     15|| `lame` option || Average kbit/s || Bitrate range kbit/s || `ffmpeg` option
    1616|| `-b 320` || 320 || 320 CBR (non VBR) example || `-b:a 320k` (NB this is 32KB/s, or its max)
    1717|| `-V 0` || 245 || 220-260 || `-q:a 0` (NB this is VBR from 22 to 26 KB/s)
     
    2222|| `-V 5` || 130 || 120-150 || `-q:a 5`
    2323|| `-V 6` || 115 || 100-130 || `-q:a 6`
    24 || `-V 7` || 100 || 80-120 || `-q:a 7`
    25 || `-V 8` || 85 || 70-105 || `-q:a 8`
    26 || `-V 9` || 65 || 45-85 || `-q:a 9`
     24|| `-V 7` || 100 || 80-120  || `-q:a 7`
     25|| `-V 8` || 85  || 70-105 || `-q:a 8`
     26|| `-V 9` || 65  || 45-85  || `-q:a 9`
    2727
    2828In our example above, we selected `-qscale:a 2`, meaning we used LAME's option `-V 2`, which gives us a VBR MP3 audio stream with an average stereo bitrate of 170-210 kBit/s.
    2929
    30 = CBR Encoding =
     30== CBR Encoding ==
    3131
    3232If you need constant bitrate (CBR) MP3 audio, you need to use the `-b:a` option instead of `-qscale:a`. Here you can specify the number of bits per second, for example `-b:a 256k` if you want 256 Kbit/s (25.6 KB/s) audio.  Available options are: 8, 16, 24, 32, 40, 48, 64, 80, 96, 112, 128, 160, 192, 224, 256, or 320 (add a `k` after each to get that rate).  So to get the highest quality setting use `-b:a 320k` (but see note below).