Sorry for that this text is so chaotic, and less informative, but at least I was able to separate all xvid option in few categories First. at the moment xvid options are separate at 2 parts I recomend all options that are available in all xvid's to be at the beggining and the rest explained in something like XviD3 unstable functions, XviD4 functions. Also the text "available with the unstable (cvs -HEAD) version of XviD", is not very accurate. In fact the HEAD is the only stable version that exists. Yes of cource, there is flag UNSTABLE that is set if these options are available. I would recomend the text "The following options are only available with the latest stable XviD 0.9.2 (api3) version and are marked as experimental and unstable. The newest development version of XviD 1.0 (api4) support them fully." Legend a - all stable versions (1,2,3 without unstable) 3 - xvid3 with UNSTABLE flag set. 4 - xvid4 (api4). !!!- xvid4 not documented so far //IN ALL XVID pass (a,3,4) bitrate (a,3,4) fixed_quant (a,3,4) me_quality (a,3,4) interlacing (a,3,4) rc_reaction_delay_factor (a,3,4) rc_averaging_period (a,3,4) rc_buffer (a,3,4) max_key_interval (a,3,4) min_key_interval (a,3,4) keyframe_boost (a,3,4) kfthreshold (a,3,4 xvid4beta2+) kfreduction (a,3,4) //NOT IN XVID4 quant_range (a,3) todo?(in 4 there are option for every case- 6 opt ions total) 4mv (a,3) - in xvid4 merged with me_quality mpeg_quant (a,3) - chenged to 'quant_type' mod_quant (a,3) - removed, break standart debug (a,3) todo (I will commit this option later) in xvid4 it is integer, not flag! powers of 2 triger debug conditions, you also need to compile xvid with _DEBUG support //ONLY IN API3 (if UNSTABLE is defined) reduced (3) divx5bvop (3) psnr (3)todo4! // IN API3 AND API4 packed (3,4) qpel (3,4) gmc (3,4) chroma_me (3,4) chroma_opt(3,4) max_bframes (3,4) (in xvid4 default 2) bquant_ratio (3,4) bquant_offset (3,4) bf_threshold (3,4) hq_ac (3,4) vhq (3,4) //NEW TO XVID4 greyscale (4) //UNDOCUMENTED //for detailed documentation you can read //transcode config module. from gomgom site. !!!quant_type - like mod_quant, possible values "mpeg", any other let it to h263 . !!!stats - print total psnr statistic (not per frame)! !!!trellis - just like ffmpeg trellis but also support mpeg quantization !!!closed_gop - forbid referencing frames outside the current Group Of Pictures !!!cartoon - set internal treshholds for compressing cartoon and anime contents !!!frame_drop_ratio !!!quant_intra_matrix - file that keeps the matrix coeficients !!!quant_inter_matrix - --||-- !!!curve_compression_high - 2pass control !!!curve_compression_low !!!overflow_control_strength (default value 5) !!!max_overflow_improvement (default value 5) !!!max_overflow_degradation (default value 5) !!!container_frame_overhead - default 24(to change if not avi) !!!par - pixel aspect ratio, 'aspect' have higher priority, accept values: 'pal43','pal169','ntsc43','ntsc169','ext' !!!par_width - only valid when par=='ext' !!!par_height - --||-- !!!turbo - //these were documented by patch !!!aspect - aspect ration. it will calculate par and if necessery par_width, par_height !!!autoaspect - same as lavc one