diff options
Diffstat (limited to 'DOCS')
-rw-r--r-- | DOCS/man/en/mplayer.1 | 45 |
1 files changed, 25 insertions, 20 deletions
diff --git a/DOCS/man/en/mplayer.1 b/DOCS/man/en/mplayer.1 index 21e9377c67..d31c8cbe7d 100644 --- a/DOCS/man/en/mplayer.1 +++ b/DOCS/man/en/mplayer.1 @@ -7709,8 +7709,11 @@ performance penalty (default: 1). . .TP .B bitrate=<value> -Sets the bitrate to be used in kbits/\:second (default: off). -This is required if you want a CBR (constant bitrate) encode. +Sets the average bitrate to be used in kbits/\:second (default: off). +Since local bitrate may vary, this average may be inaccurate for +very short videos (see ratetol). +Constant bitrate can be achieved by combining this with vbv_maxrate, +at significant reduction in quality. . .TP .B qp_constant=<1\-51> @@ -7756,10 +7759,8 @@ The third pass (pass=3) is the same as the second pass, except that it has the second pass' stats to work from. You can use all encoding options, including CPU-hungry ones. .br -The first pass may use either constant bitrate or constant quantizer. -Constant quantizer is often slightly better, but requires that you guess a -qp_constant that is somewhere near your desired bitrate. -(It is better to err on the side of lower qp_constant, i.e.\& higher bitrate.) +The first pass may use either average bitrate or constant quantizer. +ABR is recommended, since it doesn't require guessing a quantizer. Subsequent passes are ABR, and must specify bitrate. .br .I @@ -7779,7 +7780,7 @@ values of keyint. . .TP .B keyint_min=<1\-keyint/2> -Sets minimum interval between IDR-frames (default: keyint * 0.4). +Sets minimum interval between IDR-frames (default: 25). If scenecuts appear within this interval, they are still encoded as I-frames, but do not start a new GOP. In H.264, I-frames do not necessarily bound a closed GOP because it is @@ -7877,30 +7878,34 @@ Slightly slows down encoding and decoding, but should save 10-15% bitrate. Unless you are looking for decoding speed, you should not disable it. . .TP -.B qp_min=<1\-51> (CBR or two pass) +.B qp_min=<1\-51> (ABR or two pass) Minimum quantizer, 10\-30 seems to be a useful range (default: 10). . .TP -.B qp_max=<1\-51> (CBR or two pass) +.B qp_max=<1\-51> (ABR or two pass) maximum quantizer (default: 51) . .TP -.B qp_step=<1\-50> (CBR or two pass) -Maximum Value by which the quantizer may be incremented/decremented between -frames (default: 1). +.B qp_step=<1\-50> (ABR or two pass) +maximum value by which the quantizer may be incremented/decremented between +frames (default: 2) . .TP -.B rc_buffer_size=<value> (CBR or two pass) -ratecontrol buffer size, in kbit (default: 1 second's worth at the bitrate you -specified) +.B ratetol=<0.1\-100.0> (ABR or two pass) +allowed variance in average bitrate (no particular units) (default: 1.0) . .TP -.B rc_init_buffer=<0.0\-1.0> (CBR only) -Set the initial ratecontrol buffer fullness (default: 0.25). +.B vbv_maxrate=<value> (ABR or two pass) +maximum local bitrate, in kbits/\:second (default: disabled) . .TP -.B rc_sens=<0\-100> (CBR only) -ratecontrol sensitivity (default: 4) +.B vbv_bufsize=<value> (ABR or two pass) +averaging period for vbv_maxrate, in kbits +(default: none, must be specified if vbv_maxrate is enabled) +. +.TP +.B vbv_init=<0.0\-1.0> (ABR or two pass) +initial buffer occupancy, as a fraction of vbv_bufsize (default: 0.9) . .TP .B ip_factor=<value> @@ -7911,7 +7916,7 @@ quantizer factor between I- and P-frames (default: 1.4) quantizer factor between P- and B-frames (default: 1.3) . .TP -.B qcomp=<0\-1> (two pass only) +.B qcomp=<0\-1> (ABR or two pass) quantizer compression (default: 0.6). A lower value makes the bitrate more constant, while a higher value makes the quantization parameter more constant. |