additional helper functions

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@3722 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/add-ons/media/media-add-ons/mixer/MixerUtils.cpp

@@ -194,3 +194,25 @@ frames_per_buffer(const media_multi_audio_format & format)
 	}
 	return frames;
 }
+
+bigtime_t
+buffer_duration(const media_multi_audio_format & format)
+{
+	bigtime_t duration = 0;
+	if (format.buffer_size > 0 && format.frame_rate > 0 && bytes_per_frame(format) > 0) {
+		duration = s_to_us((format.buffer_size / bytes_per_frame(format)) / format.frame_rate);
+	}
+	return duration;
+}
+
+double
+us_to_s(bigtime_t usecs)
+{
+	return (usecs / 1000000.0);
+}
+
+bigtime_t
+s_to_us(double secs)
+{
+	return (bigtime_t) (secs * 1000000.0);
+}

src/add-ons/media/media-add-ons/mixer/MixerUtils.h

@@ -12,6 +12,8 @@ void CopySamples(float *_dst, int32 _dst_sample_offset,
 				 const float *_src, int32 _src_sample_offset,
 				 int32 _sample_count);
 
+bigtime_t buffer_duration(const media_multi_audio_format & format);
+
 int bytes_per_sample(const media_multi_audio_format & format);
 
 int bytes_per_frame(const media_multi_audio_format & format);
@@ -22,3 +24,6 @@ bigtime_t duration_for_frames(double framerate, int64 frames);
 
 int ChannelMaskToChannelType(uint32 mask);
 uint32 ChannelTypeToChannelMask(int type);
+
+double us_to_s(bigtime_t usecs);
+bigtime_t s_to_us(double secs);