> What does the -X parameter do exactly?
When LAME searches for a "good" quantization, it has to compare
the actual one with the best one found so far.
The function quant_compare says which one is better, the best
so far or the actual.
Now the -X parameter selects between different approaches to
make this decision:
-X0 the actual is better
if it has less distorted scalefactor bands,
or if it's equal to the best so far
and the sum of noise over the thresholds is less
than the best so far
-X1 the actual is better
if the maximum noise over all scalefactor bands is less
than the best so far
-X2 the actual is better
if the total sum of noise is lower than the best so far
-X3 the actual is better
if the total sum of noise is lower than the best so far
and the maximum noise over all scalefactor bands
is less than the best so far plus 2db.
-X4 this is a bit complicated, I think Greg Maxwell should
explain this ;)
-X5 the actual is better
if the sum of noise over the thresholds is less
than the best so far
or if they are equal
and the total sum of noise is lower than the best so far
-X6 the actual is better
if the sum of noise over the thresholds is less
than the best so far
or if they are equal
and if the maximum noise over all scalefactor bands is less
than the best so far
or if they are equal
and the total sum of noise is less or equal
the best so far
All these are EXPERIMENTAL and may disappear sooner or later.
Maybe we find the one and only criterion someday.
I hope it's getting a bit clearer to you. For the details take a look
at quantice.c, search for experimentalX.
Robert
PS: -X6 is new, I just checked it in
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