diff options
Diffstat (limited to 'sound/timestamp.h')
| -rw-r--r-- | sound/timestamp.h | 38 |
1 files changed, 29 insertions, 9 deletions
diff --git a/sound/timestamp.h b/sound/timestamp.h index 218198dcf7..2e8689a81d 100644 --- a/sound/timestamp.h +++ b/sound/timestamp.h @@ -39,24 +39,36 @@ namespace Audio { class Timestamp { protected: /** - * The millisecond part of this timestamp. - * The total time represented by this timestamp is + * The seconds part of this timestamp. + * The total time in seconds represented by this timestamp can be * computed as follows: - * _msecs + 1000 * _numberOfFrames / _framerate + * _secs + (double)_numberOfFrames / _framerate */ - uint _msecs; + uint _secs; /** - * The number of frames which together with _msecs encodes + * The number of frames which together with _secs encodes * the timestamp. The total number of frames represented * by this timestamp is computed as follows: - * _numberOfFrames + _msecs * _framerate / 1000 + * _numberOfFrames + _secs * _framerate */ int _numberOfFrames; - /** The framerate, i.e. the number of frames per second. */ + /** + * The internal framerate, i.e. the number of frames per second. + * This is computed as the least common multiple of the framerate + * specified by the client code, and 1000. + * This way, we ensure that we can store both frames and + * milliseconds without any rounding losses. + */ int _framerate; + /** + * Factor by which the original framerate specified by the client + * code was multipled to obtain the internal _framerate value. + */ + int _framerateFactor; + public: /** * Set up a timestamp with a given time and framerate. @@ -72,7 +84,13 @@ public: */ Timestamp convertToFramerate(int newFramerate) const; + /** + * Check whether to timestamps describe the exact same moment + * in time. This means that two timestamps can compare + * as equal even if they use different framerates. + */ bool operator==(const Timestamp &ts) const; + bool operator!=(const Timestamp &ts) const; // bool operator<(const Timestamp &ts) const; // bool operator<=(const Timestamp &ts) const; @@ -82,14 +100,16 @@ public: /** * Returns a new timestamp, which corresponds to the time encoded * by this timestamp with the given number of frames added. + * @param frames number of frames to add */ Timestamp addFrames(int frames) const; /** * Returns a new timestamp, which corresponds to the time encoded * by this timestamp with the given number of milliseconds added. + * @param msecs number of milliseconds to add */ - Timestamp addMsecs(int ms) const; + Timestamp addMsecs(int msecs) const; /** * Computes the number of frames between this timestamp and ts. @@ -108,7 +128,7 @@ public: uint32 msecs() const; /** Return the framerate used by this timestamp. */ - int getFramerate() const { return _framerate; } + int getFramerate() const { return _framerate / _framerateFactor; } }; |