AAC VBR or CBR - which has the best sound quality?

[admin_exported]

Can anybody give me an answer to this poser?

It seems most people regard AAC as having better sound quality than MP3. But is it better to use AAC VBR over AAC CBR?

As with everything, it's never clear cut. But without rousing the pedants, I hope to get a YES or NO answer.

I will be using 320kbps files - that will be good enough though.

 

[GazzyP]

VBR is going to produce smaller, more effciently encoded files. So the encoder can drop below 320kbps when needed: so for example if there is a section of silence in the music the encoder will drop the bit rate level below 320kbps, where as standard AAC files would fill the file full of zeros at a rate of 320kbps. A crude example as you are not going to be encoding files of silence, but gives you an idea.

You 'shouldnt' be able to tell the difference between standard AAC and AAC VBR. But some people are more sensitive to different encoding than others. There is no YES or NO answer to this - you are going to have to encode some files in the different formats and audition them side by side. But I would guess you will hear no difference.

At the end of the day VBR is going to give you smaller files - that is the main advantage. ButI do wonder if the type of music you are encoding will have an impact on the files size with VBR - so something with a constant high level of music detail such as rock or pop is less likely to benefit from VBR than say classical which has big drops and differences in music level.

 

[Anonymous]

Thanks for the response. From what I've read, it seems that the whole point of VBR is to make files smaller and so save valuable disk space. It's just that some say, VBR sounds better. Therefore, for sound quality I would expect CBR files to be better. As you say, I doubt most people would hear a difference. I am a discerning listener, but I no longer have a high end system and will only be listening to my ipod through a Denon mini.

Unless you have good quality hi-fi, an ipod through headphones (even cheap ones) will be more revealing of the original recording, such as the original master tape hiss and limitations of multi-layered recordings. I suspect that if VBR recorded files cause any subtle changes/degredation to the quality of the music, it will more likely be heard when listening in this way.

 

[idc]

Apple lossless files have a VBR as well. In my itunes the highest bit rate is 1156kbps with a Blondie track and the lowest is 317kbps with a Beethoven piano sonata. Both sound fine.