Changes between Version 50 and Version 51 of Encode/HighQualityAudio


Ignore:
Timestamp:
Aug 12, 2016, 1:11:15 AM (3 years ago)
Author:
mjbrown
Comment:

consistent use of 'range' and 'Kbps' (not sure what's really preferred), and 'FFmpeg'. moved VBR note to end

Legend:

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  • Encode/HighQualityAudio

    v50 v51  
    4848}}}
    4949{{{#!comment
    50 I think we should do a listening test between libfaac and eac3/ac3, because from my experience libfaac can't really handle 128kbps or 160kbps as well as ac3
     50I think we should do a listening test between libfaac and eac3/ac3, because from my experience libfaac can't really handle 128Kbps or 160Kbps as well as ac3
    5151libopus >= libvorbis >= aac >= libfdk_aac > libmp3lame > eac3/ac3 >= libfaac > libtwolame > mp2 > vorbis > wmav2/wmav1
    5252Both libfaac and ac3 have annoying sounds at 128Kbps. It probably depends on what one prefers, but ac3 is definitely better than libtwolame at 128Kbps. libtwolame completely breaks down at that rate.
     
    104104- '''libvorbis''' Usable range >= 96Kbps. Recommended range '''-aq 4 (>= 128Kbps)'''[[BR]]
    105105- '''libmp3lame''' Usable range >= 128Kbps. Recommended range '''-aq 2 (>= 192Kbps)'''[[BR]]
    106 - '''ac3 or eac3''' Usable range >= 160kbps. Recommended range '''>= 160Kbps'''[[BR]]
    107 - '''libfaac''' Usable range >= 160kbps. Recommended range '''-q:a 330 -cutoff 15000 (>= 192Kbps)'''.[[BR]]
     106- '''ac3 or eac3''' Usable range >= 160Kbps. Recommended range '''>= 160Kbps'''[[BR]]
     107- '''libfaac''' Usable range >= 160Kbps. Recommended range '''-q:a 330 -cutoff 15000 (>= 192Kbps)'''.[[BR]]
    108108 Example of usage:
    109109{{{
    110110ffmpeg -i input.wav -c:a libfaac -q:a 330 -cutoff 15000 output.m4a
    111111}}}
    112 - '''aac''' Usable range >= 32kbps (depending on profile and audio). Recommended rate '''>= 128Kbps'''[[BR]]
     112- '''aac''' Usable range >= 32Kbps (depending on profile and audio). Recommended range '''>= 128Kbps'''[[BR]]
    113113 Example of usage:
    114114{{{
    115115ffmpeg -i input.wav output.m4a
    116116}}}
    117 - '''libtwolame''' Usable range >= 192kbps. Recommended range '''>= 256Kbps'''[[BR]]
    118 - '''mp2''' Usable range >= 320kbps. Recommended range '''>= 320Kbps'''[[BR]]
     117- '''libtwolame''' Usable range >= 192Kbps. Recommended range '''>= 256Kbps'''[[BR]]
     118- '''mp2''' Usable range >= 320Kbps. Recommended range '''>= 320Kbps'''[[BR]]
    119119
    120120The '''vorbis''' and '''wmav1/wmav2''' encoders are not worth using.[[BR]]
    121121The '''wmav1/wmav2''' encoder '''does not reach transparency at any bitrate'''.[[BR]]
    122 The '''vorbis''' encoder does not use the bitrate specified in ffmpeg. On some samples it does sound reasonable, but the bitrate is very high.[[BR]][[BR]]
     122The '''vorbis''' encoder does not use the bitrate specified in FFmpeg. On some samples it does sound reasonable, but the bitrate is very high.[[BR]][[BR]]
    123123To calculate the bitrate to use for multi-channel audio: (bitrate for stereo) x (channels / 2).[[BR]]
    124124Example for 5.1(6 channels) Vorbis audio: 128Kbps x (6 / 2) = 384Kbps[[BR]]
    125125----
    126126
    127 Some codecs have a more efficient variable bitrate (VBR) mode which optimizes to a given, constant quality level rather than having variable quality at a given, constant bitrate (CBR). The info above is for CBR. VBR is more efficent than CBR but may not be as hardware-compatible.[[BR]]
    128127When compatibility with hardware players doesn't matter then use `libvorbis` in a MKV container rather than `libfaac` when `libfdk_aac` isn't available.[[BR]]
    129128When compatibility with hardware players does matter then use libmp3lame or ac3 in a MP4/MKV container rather than `libfaac` when `libfdk_aac` isn't available.[[BR]]
    130129Transparency means the encoded audio sounds indistinguishable from the audio in the source file.[[BR]]
     130Some codecs have a more efficient variable bitrate (VBR) mode which optimizes to a given, constant quality level rather than having variable quality at a given, constant bitrate (CBR). The info above is for CBR. VBR is more efficent than CBR but may not be as hardware-compatible.[[BR]]
    131131[[BR]]
     132