ở đây có so sánh về kĩ thuật ném ABR và VBR. ABR kế thừa ưu điểm của VBR và CBR, có thể đoạn được size của file convert. có đoạn này mà mình đọc cũng không hiểu toàn bộ nên để luôn
In terms of quality, generally VBR > ABR > CBR at the same approximate size and bitrate.
CBR only has a limited "bit reservoir" to allow limited borrowing of bits from easier passages to assist with difficult ones.
VBR uses the acoustic model and quality level to determine the amount of bits used and their distribution. Encoders with sub-optimum acoustic models procuced miserable VBR results, clouding the early reputation of VBR.
ABR is a compromise, using a VBR-style distribution of bitrate, but subject to an overrall target bitrate, rater tha an overall target quality irrespective of bitrate.
As soon as you depart from CBR, you lose the exact correlation beteween data and time, usually resulting in problem with capacity estaimates at the very least.
Basically, for maximum quality in the space avaialble, or minimum space for whatever quality you consider acceptable - VBR.
If your player or software has any issues with VBR , USE CBR
There are few good applications for ABR... anything incompatible with VBR is likely to have problems with ABR, and if targeting a particular size, selecting & testing VBR is better.