Reply to thread

Message: <blockquote data-quote="davidf" data-source="post: 660805" data-attributes="member: 19484">Maths Help...I knew my Maths, Statistics and Computing degree would come in useful at some point.The biggest question I have is how accurate do you want the clock to be 1 ms, 0.1 ms or 0.01 ms, you can't get any more accurate than the last under windows (at least you can't guarantee to be more accurate than that).I assume that what you really want is to use the Audio clock as the real reference and adjust it using the system time to interpolate.  The stream timestamp isn't really useful as you an't tell how much is buffered (50ms by default in your Audio Renderer) so there is an x amount of error in that where x<50 ms.so you want a clock like:[code]06643102617152420310542039466214674621543402184296302558430268713027293303650330374093043492304414730473513047840305119230516803052411323082836409983642158364287736668463671519367217736756623676198367920836797683685797369118437011903798574380078438014033803102380759638082483810444382781238289313829881383182438340043834759386617838668843867430386822938688363869478387346638741053876923387742938803713881068388412238981933902350390307739041033909902391088839116803920763397089640175794019204[/code]I assume.Ah I see what you mean now.  It's possible for clock to go backwards (by a few nano seconds) when you interpolate if you manage to query at just the wrong time.If you use the audio clock as the correct clock then from your example:use the system clock when paused or -ve,  when audio clock becomes active then add to the current time the difference in the clocks i.e. current reference clock time is 2 * system time - Audio clock time and use increments in the audio clock to maintain this time.  To get an interpolated time add the difference between the last 2 system clocks then take it away when adding the audio clock increase again.  I'll knock up a speadsheet and show you what I mean.[USER=10858]tourettes[/USER]if you give me a longer stream with a few pauses it'll make it easier to show you want I mean.Here's a simply piece of pseudo code of what I mean (I've assumed I'm right about the stream time)[code]SetTimestamps(LONGLONG systemTime,LONGLONG rendererTime, bool rendererInUse){if (m_lastRendererInUse && rendererInUse) m_referenceClock+=rendererTime-m_lastrendererTime; //only use audio renderer time if in use throughoutelse m_referenceClock+=systemTime-m_lastsystemTime;m_lastRendererInUse=rendererInUse;m_lastrendererTime=rendererTime;m_lastsystemTime=systemTime;} LONGLONG GetCurrentTime(){return m_referenceClock+GetCurrentSystemTime-m_lastsystemTime; //you could correct the systemtime to audio time here if desired and m_lastRendererInUse was true.  Drift doesn't matter if paused??}[/code]I find it unlikely it's this easy but at least you can point out the bit I haven't understood properly.</blockquote>

Verification