AAC quality
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AAC quality
I'm confused by the available VBR quality settings in the latest versions of Handbrake. I've read up on the quality settings elsewhere, and they go from 1 to 5, the one I most likely want is 4, LC-AAC at a moderate (64kbs per channel or so) rate. I'm currently using 384kbs CBR with 5.1 channels and it seems fine, so I want to more or less match it and hopefully save some space. However, when I select AAC VBR (quality) in Handbrake my choices go from 1 to 10. I can find no reference anywhere as to what those quality levels specifically mean or which one would match my needs most closely. Where can I find an explanation?
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Deleted User 13735
Re: AAC quality
They are there for reference. No meaningful index for vbr audio quality I know of, and AAC is, well, AAC.
Re: AAC quality
I researched my own question, and since hundreds of people have looked at this topic I will post what I have found out so far. I don't have an answer for what the quality numbers actually mean in Handbrake's AAC encoder. For an example of what I'm looking for, here is an explanation of the Nero encoder quality levels.
https://hydrogenaud.io/index.php/topic,44310.0.html
What my reading indicated is that the VBR for AAC in Handbrake doesn't function properly anyway, or at least not well enough to recommend a particular setting to accomplish what I want. In addition, unless you go to some trouble and compile your own binary with FDK-AAC (or you have a MAC), the AAC encoder in Handbrake (libav) isn't very good. Some choices are to simply use Handbrake's CBR AAC with 384 kbps with a 5.1 mixdown (which sounds OK to me), or use a demuxer/remuxer and convert the soundtracks in a different program. Keep in mind that Handbrake does not support DTS (or TrueHD) beyond the "core", so no lossless or more than 5.1 is in your input anyway if you keep your conversion inside of Handbrake.
This is what I did:
I downloaded and installed MKVToolNix GUI and InviskaMKVextract GUI. This allows me to see, demux, extract and remux the various tracks.
I installed Winamp, which installs the Fraunhofer floating-point AAC encoder FHG-AAC. FHG-AAC has 6 VBR quality levels, with 4-6 using LC-AAC. Lower levels will use various types of HE-AAC, which are of lower quality. I used this with Foobar2000, which has additional components that allow decoding of DTS-HD-MA and AC-3.
Now I can examine a MKV to see what audio tracks are available, extract the best one and re-encode it to AAC (with 7.1 channels if the original has them). I haven't decided what quality level to use, 4 is probably good enough, but even at quality 6, a 7.1 channel 48khz/24bit DTS-MA track compresses down' to about 600 kbps, about the same as AC-3.
This seems like a lot of work, but once you get it set up it is no big deal and you only spend a few minutes per movie doing it.
https://hydrogenaud.io/index.php/topic,44310.0.html
What my reading indicated is that the VBR for AAC in Handbrake doesn't function properly anyway, or at least not well enough to recommend a particular setting to accomplish what I want. In addition, unless you go to some trouble and compile your own binary with FDK-AAC (or you have a MAC), the AAC encoder in Handbrake (libav) isn't very good. Some choices are to simply use Handbrake's CBR AAC with 384 kbps with a 5.1 mixdown (which sounds OK to me), or use a demuxer/remuxer and convert the soundtracks in a different program. Keep in mind that Handbrake does not support DTS (or TrueHD) beyond the "core", so no lossless or more than 5.1 is in your input anyway if you keep your conversion inside of Handbrake.
This is what I did:
I downloaded and installed MKVToolNix GUI and InviskaMKVextract GUI. This allows me to see, demux, extract and remux the various tracks.
I installed Winamp, which installs the Fraunhofer floating-point AAC encoder FHG-AAC. FHG-AAC has 6 VBR quality levels, with 4-6 using LC-AAC. Lower levels will use various types of HE-AAC, which are of lower quality. I used this with Foobar2000, which has additional components that allow decoding of DTS-HD-MA and AC-3.
Now I can examine a MKV to see what audio tracks are available, extract the best one and re-encode it to AAC (with 7.1 channels if the original has them). I haven't decided what quality level to use, 4 is probably good enough, but even at quality 6, a 7.1 channel 48khz/24bit DTS-MA track compresses down' to about 600 kbps, about the same as AC-3.
This seems like a lot of work, but once you get it set up it is no big deal and you only spend a few minutes per movie doing it.