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Activity Forums AJA Video Systems LHi audio sync problem

  • LHi audio sync problem

    Posted by Sato Masashi on May 18, 2010 at 12:20 pm

    The problem.
    I work with FCP 7.02 on Mac Pro with Aja Kona LHi(driver 7.5.1NDD).
    I am monitoring on LMD2030(via Kona SDIout),and HDTV(via Kona HDMIout).
    Strage is RAID0(x3)320MB/s

    Some time, when I play the timeline, the audio wil go out of sync from video.
    It looks like the audio file is playing slower than the video file
    It happen intermitten.

    help me! prease!

    John Fishback replied 15 years, 11 months ago 3 Members · 7 Replies
  • 7 Replies
  • Gary Adcock

    May 18, 2010 at 1:06 pm

    [sato masashi] “Some time, when I play the timeline, the audio wil go out of sync from video. “

    Make sure all your audio is 24 bit 48K

    make sure there are no gaps in the audio tracks

    try doing an audio mixdown within FCP.

    gary adcock
    Studio37
    HD & Film Consultation
    Post and Production Workflows for the Digitally Inclined
    Chicago, IL

    https://blogs.creativecow.net/24640

  • Sato Masashi

    May 19, 2010 at 6:41 pm

    hi,gary adcock
    thank you for your reply.

    I make sure all your audio is 24 bit 48K

    I make sure there are no gaps in the audio tracks

    I try doing an audio mixdown within FCP.

    I delete FCP preference files,and reboot.

    but,Some time, when I play the timeline, the audio wil go out of sync from video.

    help me.

  • Gary Adcock

    May 20, 2010 at 1:47 pm

    Sato-san,

    what is your original format?
    what are your timeline settings?

    This is a problem with all of the DSLR camera formats, none of those cameras support 24bit audio at capture. So the audio has to be rendered for playback and RT extreme is rendering audio files faster than it is rendering video files.
    A complete render of your timeline will solve this issue 99.99% of the time.

    Turn off RT extreme (use SAFE Mode) and render your timeline completely.

    gary adcock
    Studio37
    HD & Film Consultation
    Post and Production Workflows for the Digitally Inclined
    Chicago, IL

    https://blogs.creativecow.net/24640

  • Sato Masashi

    May 21, 2010 at 1:09 am

    Adcock-san.

    original format:ProresHQ(captured by LHi,from HDW-1800 HDCAM deck)
    timeline format:ProresHQ

    So,I don’t have to Render.
    Timeline isn’t red From the start.

    I Turn off RT extreme.but,not sync.

    thank you.

  • Gary Adcock

    May 21, 2010 at 1:54 pm

    [sato masashi] “I Turn off RT extreme.but,not sync.

    are there any gaps in your timeline?
    any audio that was not captured from HDCam source tape?

    Voice over
    Narration?
    External Music?
    and On-screen Graphics?

    any of these can cause render to shift.

    gary adcock
    Studio37
    HD & Film Consultation
    Post and Production Workflows for the Digitally Inclined
    Chicago, IL

    https://blogs.creativecow.net/24640

  • Sato Masashi

    May 22, 2010 at 1:24 pm

    Thank you for your reply,Mr gary adcock.

    I tested.1

    1.Rec interview with camera mic.
    2.Play back check,with HDW1800 LCDmonitormonitor+monitor out.
    it’s just sync.
    3.Capture with LHi on SDI+SDIembeded audio. Prores setting.
    4.I put only 1 clip on FCPtimeline.
    5.playback sometimes.

    Some time, when I play the timeline, the audio wil go out of sync from video.
    It happen intermitten.

  • John Fishback

    May 26, 2010 at 7:26 pm

    Do you always start play with the playhead on the first frame? If you start in the empty portion of the sequence you may lose sync. This happened to me recently. I had to insert a slug into any empty spaces in the timeline (audio or video) and then the sync was good. I read of someone else having this problem a month or two ago, but had never seen it myself until two weeks ago.

    John

    MacPro 8-core 2.8GHz 8 GB RAM OS 10.5.8 QT7.6.4 Kona 3 Dual Cinema 23 ATI Radeon HD 3870, 24″ TV-Logic Monitor, ATTO ExpressSAS R380 RAID Adapter, PDE enclosure with 8-drive 6TB RAID 5
    FCS 3 (FCP 7.0.2, Motion 4.0.2, Comp 3.5.2, DVDSP 4.2.2, Color 1.5.2)

    Pro Tools HD w SYNC IO & 192 Digital I/O, Yamaha DM1000, Millennia Media HV-3C, Neumann U87, Schoeps Mk41 mics, Genelec Monitors, PrimaLT ISDN

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