Complex sentence: Older formats such as AVI do not support new codec features like B-frames, VBR audio, VFR natively, although the format may be "hacked" to add support, creating compatibility problems.
Split into simpler sentences: Older formats such as AVI do not support new codec features like B-frames, VBR audio, VFR natively. The format may be "hacked" to add support, but this creates compatibility problems.