diff options
| -rw-r--r-- | src/pulse/volume.c | 42 | ||||
| -rw-r--r-- | src/pulse/volume.h | 6 |
2 files changed, 33 insertions, 15 deletions
diff --git a/src/pulse/volume.c b/src/pulse/volume.c index a9622e784..e48c77734 100644 --- a/src/pulse/volume.c +++ b/src/pulse/volume.c @@ -120,20 +120,28 @@ pa_volume_t pa_sw_volume_divide(pa_volume_t a, pa_volume_t b) { return pa_sw_volume_from_linear(pa_sw_volume_to_linear(a) / v); } -#define USER_DECIBEL_RANGE 90 +/* Amplitude, not power */ +static double linear_to_dB(double v) { + return 20.0 * log10(v); +} + +static double dB_to_linear(double v) { + return pow(10.0, v / 20.0); +} pa_volume_t pa_sw_volume_from_dB(double dB) { - if (isinf(dB) < 0 || dB <= -USER_DECIBEL_RANGE) + if (isinf(dB) < 0 || dB <= PA_DECIBEL_MININFTY) return PA_VOLUME_MUTED; - return (pa_volume_t) lrint(ceil((dB/USER_DECIBEL_RANGE+1.0)*PA_VOLUME_NORM)); + return pa_sw_volume_from_linear(dB_to_linear(dB)); } double pa_sw_volume_to_dB(pa_volume_t v) { - if (v == PA_VOLUME_MUTED) + + if (v <= PA_VOLUME_MUTED) return PA_DECIBEL_MININFTY; - return ((double) v/PA_VOLUME_NORM-1)*USER_DECIBEL_RANGE; + return linear_to_dB(pa_sw_volume_to_linear(v)); } pa_volume_t pa_sw_volume_from_linear(double v) { @@ -141,18 +149,28 @@ pa_volume_t pa_sw_volume_from_linear(double v) { if (v <= 0.0) return PA_VOLUME_MUTED; - if (v > .999 && v < 1.001) - return PA_VOLUME_NORM; + /* + * We use a cubic mapping here, as suggested and discussed here: + * + * http://www.robotplanet.dk/audio/audio_gui_design/ + * http://lists.linuxaudio.org/pipermail/linux-audio-dev/2009-May/thread.html#23151 + */ - return pa_sw_volume_from_dB(20.0*log10(v)); + return (pa_volume_t) (cbrt(v) * PA_VOLUME_NORM); } double pa_sw_volume_to_linear(pa_volume_t v) { + double f; - if (v == PA_VOLUME_MUTED) + if (v <= PA_VOLUME_MUTED) return 0.0; - return pow(10.0, pa_sw_volume_to_dB(v)/20.0); + if (v == PA_VOLUME_NORM) + return 1.0; + + f = ((double) v / PA_VOLUME_NORM); + + return f*f*f; } char *pa_cvolume_snprint(char *s, size_t l, const pa_cvolume *c) { @@ -225,7 +243,7 @@ char *pa_sw_cvolume_snprint_dB(char *s, size_t l, const pa_cvolume *c) { l -= pa_snprintf(e, l, "%s%u: %0.2f dB", first ? "" : " ", channel, - isinf(f) < 0 || f <= -USER_DECIBEL_RANGE ? -INFINITY : f); + isinf(f) < 0 || f <= PA_DECIBEL_MININFTY ? -INFINITY : f); e = strchr(e, 0); first = FALSE; @@ -249,7 +267,7 @@ char *pa_sw_volume_snprint_dB(char *s, size_t l, pa_volume_t v) { f = pa_sw_volume_to_dB(v); pa_snprintf(s, l, "%0.2f dB", - isinf(f) < 0 || f <= -USER_DECIBEL_RANGE ? -INFINITY : f); + isinf(f) < 0 || f <= PA_DECIBEL_MININFTY ? -INFINITY : f); return s; } diff --git a/src/pulse/volume.h b/src/pulse/volume.h index ddedca7d7..b56777855 100644 --- a/src/pulse/volume.h +++ b/src/pulse/volume.h @@ -212,10 +212,10 @@ pa_volume_t pa_sw_volume_divide(pa_volume_t a, pa_volume_t b) PA_GCC_CONST; * *dest. This is only valid for software volumes! \since 0.9.13 */ pa_cvolume *pa_sw_cvolume_divide(pa_cvolume *dest, const pa_cvolume *a, const pa_cvolume *b); -/** Convert a decibel value to a volume. This is only valid for software volumes! */ +/** Convert a decibel value to a volume (amplitude, not power). This is only valid for software volumes! */ pa_volume_t pa_sw_volume_from_dB(double f) PA_GCC_CONST; -/** Convert a volume to a decibel value. This is only valid for software volumes! */ +/** Convert a volume to a decibel value (amplitude, not power). This is only valid for software volumes! */ double pa_sw_volume_to_dB(pa_volume_t v) PA_GCC_CONST; /** Convert a linear factor to a volume. This is only valid for software volumes! */ @@ -227,7 +227,7 @@ double pa_sw_volume_to_linear(pa_volume_t v) PA_GCC_CONST; #ifdef INFINITY #define PA_DECIBEL_MININFTY ((double) -INFINITY) #else -/** This value is used as minus infinity when using pa_volume_{to,from}_dB(). */ +/** This floor value is used as minus infinity when using pa_volume_{to,from}_dB(). */ #define PA_DECIBEL_MININFTY ((double) -200.0) #endif |