[flac-dev] Residual bps and encoding speed

lvqcl lvqcl.mail at gmail.com
Mon Jun 30 13:29:27 PDT 2014

I changed the condition in *_precompute_partition_info_sums_*()
functions from
     if(bps <= 16)
     if(FLAC__bitmath_ilog2(default_partition_samples) + bps < 32)

and then changed the 'subframe_bps' argument of find_best_partition_order_()
in evaluate_fixed_subframe_() and evaluate_lpc_subframe_() as follows:

    evaluate_fixed_subframe_():    evaluate_lpc_subframe_():
1) subframe_bps + order           subframe_bps + 0
2) subframe_bps + order           subframe_bps + 2
3) subframe_bps + order           subframe_bps + 4
4) subframe_bps + 4               subframe_bps + 4

Version 0 hangs during encoding. So Miroslav was right, it is necessary
to increase bps for lpc subframes as well. Versions 1...3 have identical
encoding speed. So it's possible to play safe and just choose
"subframe_bps + 4" in both cases. This is equivalent to the patch in
(this patch also adds 4 to subframe_bps, but in different place).

So I think it's a matter of taste which patch to prefer: this --
or this --

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