Opus tuning

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Revision as of 00:21, 29 December 2012 by Jmspeex (Talk | contribs)

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This page is meant to provide help on tuning the current Opus encoder. It assumes you are working on the master branch, not 1.0.x. As work progresses, some info (especially any line numbers) may become outdated. The numbers in parentheses represent (in order):

  • Impact on quality
  • Quality of current tuning
  • Difficulty

Parameters

tonality (10 5 1)

around line 1574 of celt_encoder.c:

       tonal_target = target + (opus_int32)((coded_bins<<BITRES)*1.2f*tonal);

Replacing the constant 1.2f will change the impact of tonality on the bit-rate. The higher value, the higher the bit-rate of tonal frames/samples.

trim (7 7 8)

dynalloc (5 5 9)

stereo saving (4 6 6)

spreading (4 7 7)

tapset (1 4 9)

transient estimator (10 8 8)

transient boost (8 6 6)

tf estimator (6 6 9)

Intensity threshold (7 8 3)

skip threshold (3 6 4)

mode/bandwidth decisions (6 4 4)