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| author | Justin Ruggles <justin.ruggles@gmail.com> | 2012-09-28 16:36:58 -0400 |
|---|---|---|
| committer | Justin Ruggles <justin.ruggles@gmail.com> | 2012-12-05 11:23:36 -0500 |
| commit | 5312268b34dc948e87934ae665a79a57c2fe2648 (patch) | |
| tree | cdc640bec5b4a544f104e854ca8f755700e04059 | |
| parent | ac7eb4cb20ea84cfc911794722695d501b354ee9 (diff) | |
| download | ffmpeg-5312268b34dc948e87934ae665a79a57c2fe2648.tar.gz | |
eval: treat dB as decibels instead of decibytes
| -rw-r--r-- | libavutil/eval.c | 27 | ||||
| -rw-r--r-- | tests/ref/fate/eval | 6 |
2 files changed, 30 insertions, 3 deletions
diff --git a/libavutil/eval.c b/libavutil/eval.c index 7887cf6b0e..a0e968dc34 100644 --- a/libavutil/eval.c +++ b/libavutil/eval.c @@ -81,7 +81,11 @@ double av_strtod(const char *numstr, char **tail) d = strtod(numstr, &next); /* if parsing succeeded, check for and interpret postfixes */ if (next!=numstr) { - if (*next >= 'E' && *next <= 'z') { + if (next[0] == 'd' && next[1] == 'B') { + /* treat dB as decibels instead of decibytes */ + d = pow(10, d / 20); + next += 2; + } else if (*next >= 'E' && *next <= 'z') { int e= si_prefixes[*next - 'E']; if (e) { if (next[1] == 'i') { @@ -339,16 +343,31 @@ static int parse_pow(AVExpr **e, Parser *p, int *sign) return parse_primary(e, p); } +static int parse_dB(AVExpr **e, Parser *p, int *sign) +{ + /* do not filter out the negative sign when parsing a dB value. + for example, -3dB is not the same as -(3dB) */ + if (*p->s == '-') { + char *next; + strtod(p->s, &next); + if (next != p->s && next[0] == 'd' && next[1] == 'B') { + *sign = 0; + return parse_primary(e, p); + } + } + return parse_pow(e, p, sign); +} + static int parse_factor(AVExpr **e, Parser *p) { int sign, sign2, ret; AVExpr *e0, *e1, *e2; - if ((ret = parse_pow(&e0, p, &sign)) < 0) + if ((ret = parse_dB(&e0, p, &sign)) < 0) return ret; while(p->s[0]=='^'){ e1 = e0; p->s++; - if ((ret = parse_pow(&e2, p, &sign2)) < 0) { + if ((ret = parse_dB(&e2, p, &sign2)) < 0) { av_expr_free(e1); return ret; } @@ -629,6 +648,8 @@ int main(int argc, char **argv) "not(1)", "not(NAN)", "not(0)", + "6.0206dB", + "-3.0103dB", NULL }; diff --git a/tests/ref/fate/eval b/tests/ref/fate/eval index dfc5ae463d..b01e5a5718 100644 --- a/tests/ref/fate/eval +++ b/tests/ref/fate/eval @@ -184,5 +184,11 @@ Evaluating 'not(NAN)' Evaluating 'not(0)' 'not(0)' -> 1.000000 +Evaluating '6.0206dB' +'6.0206dB' -> 2.000000 + +Evaluating '-3.0103dB' +'-3.0103dB' -> 0.707107 + 12.700000 == 12.7 0.931323 == 0.931322575 |