thomsens;389686 Wrote: > Does MP3 VBR target an average bit rate therefore having some samples > higher and some lower than the target bitrate specified? Or, is the > bitrate specified the maximum sample rate for the encode and naturally > it can encode some samples safely at a lower bitrate therefore reducing > files size? In other words is a 192K CBR encode better or worse than a > 192K VBR encode? In theory if 192K was a true average, then the VBR > approach should be a better encode unless of course the passage is > extremely complex in which case I suppose it would come in very similar > to CBR.
Speaking only of what I know about the LAME Mp3 encoder and its options: That's about right. In addition to CBR and VBR settings, there's also ABR, which is a form of variable bitrate that attempts to target an overall average bitrate. This is a little more in line with what you've called VBR. Mp3's are encoded in blocks called frames, each of which can have a different bitrate. This is how you can have "variable" bitrate encoding. Both ABR and VBR use this to their advantage by encoding some frames at a higher rate and some at a lower rate, taking advantage of the differences in complexity in parts of the audio being encoded. The overall effect is usually a higher quality encoding than would be achieved through CBR encoding. Unlike ABR, VBR tries to target a perceived _quality_ level. For the most part, that tends to end up within a certain a bitrate range over the course of an entire track, but the actual overall bitrate for a track is a product of the actual audio being encoded. VBR is definitely the way to go for most uses if you're looking for the best possible quality for a given file size. The exception to this would be encoding for other applications, such as streaming the Mp3 across the 'net. Most internet radio streams and music services are encoded in CBR. Check out the chart in the middle of this wiki page for the approximate bitrate range for the different VBR quality levels: http://wiki.hydrogenaudio.org/index.php?title=Lame The page also answers some questions regarding relative quality of VBR vs ABR vs CBR. -- JJZolx Jim ------------------------------------------------------------------------ JJZolx's Profile: http://forums.slimdevices.com/member.php?userid=10 View this thread: http://forums.slimdevices.com/showthread.php?t=58868 _______________________________________________ ripping mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/ripping
