By the way what is the best audio grabber program nowadays? Is it still EAC? I'm really out of this game lately. :)Oh, and how to create separate audio tracks for gapless playback on any basic player? I just see your Wiki... There used to be a command line solution to cut the audio files at the block's ends so every simple player can play 'em back gaplessly. It worked for MP3. Does it work for OGG?
Default is king, ain't it?
As far as the quality-bitrate tradeoff goes, Opus (homepage, FAQ) is easily the best codec available for audiobook use. Already at 24kbps it's quite close to the original. (That's 97 hours of audiobooks per GB of storage, vs 1 hour 40 minutes for CD or 18 hours for the 128kbps AAC eahm was suggesting.).....The command line isn't as scary as you think. If the command line really is a problem you can use Foobar2000 to encode to Opus instead.
encoder: Yes, Opus is also somewhat better than the competition (AAC/Vorbis) for music, though not by as large a margin.DonP, I think you'll find that increasing the bitrate from 10kbps to 12kbps, which gives mediumband (6kHz) rather than narrowband (4kHz) audio bandwidth, will make your audiobooks sound considerably better without much of a bitrate change. Since most of the energy in sibilants (s-sounds etc) is around 4-6kHz, and since there's energy in that range even for vowels, the quality difference between narrowband and mediumband speech is quite large, probably just as large as the quality difference between mediumband and the superwideband you get at 22kbps.
I encoded some acoustic guitar music at 64kb/s and it just sounded wrong.. a little mushy.
1.0.1 is actually restricted VBR. Tonality (guitar as well) is an issue for 1.0.1Maybe You will want to try the last experimental branch which is pretty good (especially for tonality) at this point .
I hope there's more efficiency to come in the rockbox decoder. I do accept that is is part of a development build, not a "stable release"
Just tested AAC Apple True VBR Q18 (~75kbps) (the average of the full audiobook was 43kbps) and I coultdn't distinguish it from the original, you can go much lower than expected with speech.
Opus (0.1.5 from opus-codec.com) --vbr 32 (~34kbps): 152MB
A brief bit about Opus's ability to deal with mixed content: if you have an audiobook with quite a bit of music content, then for the time being, to get the full benefit of Opus's ability to code both speech and music, you need to be using an encoder newer than the one currently offered at opus-codec.org (for instance, this one)and you need to be encoding at 30kbps or higher.