WAV files to test Latency, Accuracy and Repeatability
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| Wav Files |
| CB244816_M2.WAV 24 fps 48KHz 16bit Stereo Files |
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| CB254816_M2.WAV 25 fps EBU 48KHz 16bit Stereo Files |
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| CB29974816_M2.WAV 29.97 fps SMPTE Non Drop 48KHz 16bit Stereo Files |
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| Latency, Accuracy and Repeatability |
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Thursday, 18 March 2010
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Computers have been standard equipment in post production for some years now. Not all have real time operation systems and latency can be a problem. When synchronizing the major problem is not accuracy but repeatability, it does not matter if there is a one frame sync error provided that there is always a one frame sync error!
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Recently I was asked to add phase compensation to the P2MMC, Jun Yamazaki who works with Tac Systems (our Japanese agents) discovered that different DAW's had a different offset error when synchronizing to MTC. To measure offset Jun recorded timecode and looked at the recorded waveform, Jun is a timecode geek like me but this is not a suitable method for everyone!
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I asked Chris Braclik (I worked with Chris when at Audio Kinetics) from Soundtrack Productions to make 3 stereo WAV files, each has one track with continuous timecode at 24, 25 or 29,97fps, starting at 00:59:55:00 and ending at 01:01:05:00. The other track has 1KHz bursts one frame long, once per second stating at 01:00:00:00 and ending at 01:01:00:00. The bursts are positioned exactly at the start of each second.
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You can use these files to check the timecode latency and more importantly the repeatability of both record and replay.
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I checked the Record on a Sadie system, there was a consistent 1/5 of a frame error when locking to LTC , I have not checked the playback yet.
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I will publish a chart of your results if I receive enough information- DAW, Platform, and Results.
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