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Hydrogenaudio Forum => Uploads => Topic started by: [JAZ] on 2015-07-26 16:42:33

Title: sample for ffmpeg aac
Post by: [JAZ] on 2015-07-26 16:42:33
This is a sample for testing the ffmpeg aac encoder.  (Related thread (http://www.hydrogenaud.io/forums/index.php?showtopic=109716) )

It shows notable dropouts and collapse of highs.

The ffmpeg version is  N-73818-g9ebe041:
    encoder        : Lavf56.40.101
    Stream #0:0: Audio: aac (libvo_aacenc) (mp4a / 0x6134706D), 44100 Hz, stereo, s16, 128 kb/s
      encoder        : Lavc56.49.101 libvo_aacenc

For comparison, a 64kbps file encoded with Apple's encoder (using qaac --cbr 64).  Even --cbr 32 --he sounds better than ffmpeg's one.

Side note: The full song is this one: https://www.youtube.com/watch?v=UjGZOD9_lTQ (https://www.youtube.com/watch?v=UjGZOD9_lTQ)
Title: sample for ffmpeg aac
Post by: [JAZ] on 2015-07-26 18:25:34
I cannot edit the post.

The settings used are "-i input.wav  output.m4a" .

This selected the libvo_aacenc at 128kbps.

Selecting the native aac encoder with:
    -c:a aac -strict experimental -b:a 128k
produces better results.
Title: sample for ffmpeg aac
Post by: 2012 on 2015-07-26 19:15:01
Similar to FDK and FAAC, vo-aacenc is just an external library FFmpeg provides a wrapper for.

FDK would have been chosen as a default AAC encoder if it was enabled in your build.
Title: sample for ffmpeg aac
Post by: bp0 on 2015-07-27 03:48:24
The VisualOn AAC encoder (vo-aacenc) is known to be very poor, but it is claimed (though disputed) to be released under a free license so it is usually included by default. The FDK encoder is not, you have build your own ffmpeg with support, or get a build with support somewhere.
From the ffmpeg AAC FAQ:
Which encoder should I use? What provides the best quality? (https://trac.ffmpeg.org/wiki/Encode/AAC#WhichencodershouldIuseWhatprovidesthebestquality)
For AAC-LC the likely answer is: libfdk_aac > libfaac > Native FFmpeg AAC encoder (aac) > libvo_aacenc.

Title: sample for ffmpeg aac
Post by: LithosZA on 2015-07-27 15:16:45
It would be nice if they also marked the vo-aacenc external library in ffmpeg as '-strict experimental'.
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