Page 1 of 1
scene times for chases
Posted: 12 Jul 2010, 02:03
by goldtop
Trying to create some basic chases. using the sequence editor, I can create the steps that make up the sequence, but it appears that timing of each scene is quantized to 100ms. That is, I can enter a step time of 0.4s or 0.5s, but nothing in between, Is this the way Freestyler works, or am I missing something?
I want to build a couple of chases synced to song tempo. Something like 109bpm is dead in the middle between 400 and 500 milliseconds.
Please let me know. Thanks.
Re: scene times for chases
Posted: 12 Jul 2010, 10:41
by Mattotone
does it realy need to be that precises 50ms is indeed very quick.
Are you going to be quick enough to be able to start a sequences with a 50ms accuracy?
Iv just tried with a stop watch to hit a 50ms window im usually 100ms or so out, to work at that accuracy youl need to be using time coded music.
Re: scene times for chases
Posted: 15 Jul 2010, 02:35
by goldtop
I appreciate the difficulty in trying to do anything real time on Windows platforms. If I were designing, I'd pick 100ms as good starting point too.
The protocol runs on a 23ms epoch (approx). That temporal resolution, I would opine, is difficult to discern indeed, and not likely to be attainable by hand. To answer your question directly, no, I probably couldn't start a chase to an accuracy of 50ms.
The bigger issue is the aliasing generated by being unable to achieve a timing as accurate as the song's tempo. If you set up a chase on a song with 109 bpm, for example, you end up at 550ms per beat. The 50ms error (i.e., having to set up at 400ms or 500ms) basically means the chase will fall in and out of time with respect to the song tempo, and relatively often. If I had finer temporal resolution in Freestyle, I may start the chase slightly early or slightly late, but I would remain more or less in time with the song (in other words, it wouldn't slip in and out of time, going early and then progressing to timely, and then progressing to late).
Its an aliasing problem - or beat patterns, if you're more inclined. The more resolute your clock, the closer you can get to the song's true tempo, which means you increase greatly the periods between clock slip between Freestyler and the song's tempo. Live bands can compensate by playing the song at 400ms or 500ms. A DJ would have a tougher time.
Understood Windows doesn't get much better than tens of milliseconds, probably 50ms is as good as it gets.
Re: scene times for chases
Posted: 15 Jul 2010, 18:37
by LJ_krede.dk
maybe you should have a look at the sound to light and tap sync feature in FS... maybe that could help you a bit
Re: scene times for chases
Posted: 30 Jul 2010, 13:53
by remco_k
goldtop wrote:
basically means the chase will fall in and out of time with respect to the song tempo, and relatively often. If I had finer temporal resolution in Freestyle, I may start the chase slightly early or slightly late, but I would remain more or less in time with the song (in other words, it wouldn't slip in and out of time, going early and then progressing to timely, and then progressing to late).
Even if FreeStyler had options to set smaller time steps like 50ms of 100ms, you would not be satisfied. The biggest problem is the inaccuracy of the timer objects FreeStyler uses. It uses default TTimer objects wich are created to trigger an event about every X msec, but are not created to trigger an event exactly every X msec. For that purpose a multimedia timer should be used, those are accurate which TTimers are not -at all-. Setting a TTimer to say 150 msec will trigger events every about 150 msec. But the time could easily be 180 msec or 160 or 140 or 200 msec, infact, rarely it hits exactly 150 msec. Depending on whats happening on the machine. Additional TTimers don't recover in time when they were late several times. Multimedia timers does.
Example, setting both a TTimer and Multimedia timer to an interval of 150msec and run them for 1 minute.
After 1 minute the Multimedia timer has triggered exactly 400 times - right on time, for sure.
But the TTimer might have triggered about somewhere between 380 and 390 times, jumping around pretty instable somewhere in that minute.
Thats one of the main reasons why the 'manual trigger' in the cue does'nt keep your tap rythm when you tapped it.
Now this is al internal in FreeStyler, you can't see that from the outside. So just makeing it possible to select 50 msec (or smaller steps) wont help you at all. The TTimer should be replaced by a multimedia timer to do a pretty good job. Thats a lot of work, and for what?
Still there is the shift of time problem - you will always have that. Just like 48 kHz on one device is never exactly the 48 kHz on another device as long as there is no sync between them.
Have a look at my Sound 2 light tool. It might help you out much better than entering fixed times.