OUTPinged_
7th June 2002, 18:42
Here it comes, simple stuff followed by more complex. User-friendly explanations are in italic.
Automatic minimum relative quality - a simple coefficient for calculating min_rel_qual variable. It automatically looks at the first to second pass ratio (GKnot users are familiar with it) and multiplies it by Strength percentage. The result is capped between 20 and 100.
minimum_relative_quality=100-(100-encode_quality)*strength<--like that
Wicked. All numbers in italic section are to be changed.
ie 1/2pass=66, strength=50, mrq will be equal to 100-(100-66)*0.50=83.
Very newbie-friendly option. The working range is 50-100, with 90-100 for 2cd rips (66%+ 1/2pass ratio) and 50-65 for 1cdrips of long movies (35-50% 1/2pass)
Bonus bias - determines how much bit (percentage) will be distributed "proportionally" and by "bias". 100 equals pure bias distro and 0 equals to pure proportional distro of bonuses. 50 gives equal amount of bits to both.
"Proportional" gives more constant quality throughout the movie while "bias" will give more bits to smaller (lo-motion) frames.
Automatic bonus bias - sets "bonus bias" equal to min_rel_qual variable value.
That one is nice. Gives pretty balanced results and one option less to get headache with. Will favor lo-motion scenes for high quality encodes and give more steady quality for 1CD rips
Minimum relative quality - a coefficient (it's a percentage, ie 33mrq is 0.33 coeff.) by which alt.cc algo multiplies *all* frame sizes *except* frames that are so small that dont fit into "low distance" range.
Ok, this one is pretty important. If you are setting it manually, you need to have some understanding about quantizers and know how high quant. values do you want to reach on high-motion scenes. To make things more simple: if 1/2pass ratio is 66%(av. quant.=3) and mrq=50, your maximum quantizer will not rise higher than quant6, even on _very_ intense scene. It is a bad idea to get out of 40-66 range of this variable, and 50 seems to me like a value close to ideal. This setting is the most responsible if your movie will look like "MAED iN FL4SK!!11(c)" or not.
High/low distance - defines a part of framesize range, which will be multiplied by "aggression" coefficient. Ranges begin at average_framesize (0), "low distance" ends at 100 (with framesize=0), "high distance" is uncapped.
It is surprisingly hard to make an encode look terrible with these, and tweaking them wont help at all if you have set MRQ wrong.
If you did not, then setting low dist. to 25-50 and high dist. to 100 with high agg. and 200 with medium and low agg. will typically yeld pretty decent results. For more "old curve compression" feel, set low. dist. to 100 or higher(codec will set it back to 100 in that case)
Aggression - a coeficient by which all frames with framesizes that are within "distances" multiplied. "Medium" is a constant multiplier and "high" and "low" are sine/cosine multipliers.
This is mostly a matter of personal preference until you are _really_ knowlegable. Begin with "medium" and when you will be getting stable results(means other settings are ok), try to change it to high/low. That change will affect quite much frames, with hih agg making "medium intensity" scenes look a tad worse(with increase of quality in hi-mo scenes) and low agg. will do the opposite.
And a hint: dont touch those "Max overflow improvement/degradation" options unless you know what they will do. They are not "max bitrate" related (are they?).
PS.I will answer questions here and will be happy if Foxer will point out if i was wrong at the descrptions somewhere.
[edit] typos atm
-------MooPolice Approved \o/
Automatic minimum relative quality - a simple coefficient for calculating min_rel_qual variable. It automatically looks at the first to second pass ratio (GKnot users are familiar with it) and multiplies it by Strength percentage. The result is capped between 20 and 100.
minimum_relative_quality=100-(100-encode_quality)*strength<--like that
Wicked. All numbers in italic section are to be changed.
ie 1/2pass=66, strength=50, mrq will be equal to 100-(100-66)*0.50=83.
Very newbie-friendly option. The working range is 50-100, with 90-100 for 2cd rips (66%+ 1/2pass ratio) and 50-65 for 1cdrips of long movies (35-50% 1/2pass)
Bonus bias - determines how much bit (percentage) will be distributed "proportionally" and by "bias". 100 equals pure bias distro and 0 equals to pure proportional distro of bonuses. 50 gives equal amount of bits to both.
"Proportional" gives more constant quality throughout the movie while "bias" will give more bits to smaller (lo-motion) frames.
Automatic bonus bias - sets "bonus bias" equal to min_rel_qual variable value.
That one is nice. Gives pretty balanced results and one option less to get headache with. Will favor lo-motion scenes for high quality encodes and give more steady quality for 1CD rips
Minimum relative quality - a coefficient (it's a percentage, ie 33mrq is 0.33 coeff.) by which alt.cc algo multiplies *all* frame sizes *except* frames that are so small that dont fit into "low distance" range.
Ok, this one is pretty important. If you are setting it manually, you need to have some understanding about quantizers and know how high quant. values do you want to reach on high-motion scenes. To make things more simple: if 1/2pass ratio is 66%(av. quant.=3) and mrq=50, your maximum quantizer will not rise higher than quant6, even on _very_ intense scene. It is a bad idea to get out of 40-66 range of this variable, and 50 seems to me like a value close to ideal. This setting is the most responsible if your movie will look like "MAED iN FL4SK!!11(c)" or not.
High/low distance - defines a part of framesize range, which will be multiplied by "aggression" coefficient. Ranges begin at average_framesize (0), "low distance" ends at 100 (with framesize=0), "high distance" is uncapped.
It is surprisingly hard to make an encode look terrible with these, and tweaking them wont help at all if you have set MRQ wrong.
If you did not, then setting low dist. to 25-50 and high dist. to 100 with high agg. and 200 with medium and low agg. will typically yeld pretty decent results. For more "old curve compression" feel, set low. dist. to 100 or higher(codec will set it back to 100 in that case)
Aggression - a coeficient by which all frames with framesizes that are within "distances" multiplied. "Medium" is a constant multiplier and "high" and "low" are sine/cosine multipliers.
This is mostly a matter of personal preference until you are _really_ knowlegable. Begin with "medium" and when you will be getting stable results(means other settings are ok), try to change it to high/low. That change will affect quite much frames, with hih agg making "medium intensity" scenes look a tad worse(with increase of quality in hi-mo scenes) and low agg. will do the opposite.
And a hint: dont touch those "Max overflow improvement/degradation" options unless you know what they will do. They are not "max bitrate" related (are they?).
PS.I will answer questions here and will be happy if Foxer will point out if i was wrong at the descrptions somewhere.
[edit] typos atm
-------MooPolice Approved \o/