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Thread: Video playback with Audio. Sync error?

  1. #1

    Question Video playback with Audio. Sync error?

    Hi, I am new to using catalyst with audio. Got a show coming up in four weeks time and using catalyst to playback audio and video triggered from MagicQ PC.

    I was advised to play the audio back on a new layer and ether use sync id or trigger both the layers at the same time.

    In testing today i found that:
    Triggering the layers together made the video out of sync with the audio by the time the clip completed (only about 12frames, but noticeable).
    -
    Syncing the layers by id kept the video and audio in sync but the layers hud had some funny jumping going on. I dont think this upset the video performance.

    Videos of 'jumping'
    http://www.youtube.com/watch?v=R7skttA_AgA
    http://www.youtube.com/watch?v=8vylwZCvBCc
    -
    Finally!
    Playing the video with audio mode 70 again kept both video and audio in sync. I did however loose the FPS reading on the layer window.


    Please could you advise me on the best option to playback video and audio using catalyst.

    Video files are 820x1024 AIC 25FPS. Audio: Linear PCM 48Hz, 16-Bit.
    Edited in FCP and exported using QT.

    Catalyst server:
    OSX 10.6.6 / 4.40_m329 / DV dongle
    MacPro 4,1 2.26 8 Core / 6GB / ATI HD 4870 / OCZ-Vertex SSD (playback)

    Thank you for helping!!
    P

  2. #2
    Join Date
    Oct 2004
    Location
    UK - Milton Keynes
    Posts
    807
    Dont know who advised playback separately - but using playmode 70-76 onwards is probably the simplest way of playing a movie with audio.

    The FPS counter will disappear, because catalyst prioritises audio playback when using these playmodes (70-76) - i.e. it plays back at the same frame rate as the clip with audio was encoded - no matter what your system frame rate is set to. This is to ensure that the audio playback is flawless and sounds like it was intended.

    So the best way to playback audio with a video file is to encode both together as one movie (eg AIC codec) and use playmode 70-76


    However - you should also check the spec of your graphics card and read this post:

    samsc.com/showthread.php?t=1908

    ATI 4870 / 5770 / 5870 have driver issues is 10.6.6/10.6.7 - and you get very poor performance when using catalyst.
    You should change your graphics card to an Nvidia card which does not have the same problems.
    The Nvidia Quadro 4000 is the best performing official card available if using Snow Leopard (as of May 2011)

    Do get back to me if you need more help

    Simon
    Simon Pugsley

    SNP Productions Ltd. (UK)
    Lighting & Video Control Solutions
    Catalyst|Sales|Hire|Training|Support
    Catalyst Dealer UK Europe & Worldwide...

    Office: +44 (0)1908 410129
    Mobile: +44 (0)7958 390034
    simon@snp-productions.co.uk
    www.snp-productions.co.uk

  3. #3
    Cheers Simon,
    Will continue testing in that play mode and look into the graphics card situation. 10.6.6 is running on my server (snug in one of your cases too!!) don't know if this problem still exists?

  4. #4
    Join Date
    Oct 2004
    Location
    UK - Milton Keynes
    Posts
    807
    yes - problem re graphics cards still exists....

    Strongly suggest changing the graphics card...
    To give an example: ATI card tests only resulted in ONE layer of HD content playback, compared to Nvidia Quadro 4000 with 8 layers of 1920x1080 25fps (AIC) playback...

    The ATI drivers are broken in 10.6.x

    (May 2011)
    Simon Pugsley

    SNP Productions Ltd. (UK)
    Lighting & Video Control Solutions
    Catalyst|Sales|Hire|Training|Support
    Catalyst Dealer UK Europe & Worldwide...

    Office: +44 (0)1908 410129
    Mobile: +44 (0)7958 390034
    simon@snp-productions.co.uk
    www.snp-productions.co.uk

  5. #5
    Quote Originally Posted by pip View Post
    I was advised to play the audio back on a new layer and ether use sync id or trigger both the layers at the same time.
    I'm not sure who advised you of this but there is only one advantage to placing audio on a separate file. That reason is to be able to adjust the inframe or outframe amounts of the video file to adjust the offset of frames between layers.

    This is an advanced technique that I have suggested to people in the past as a workaround but this is not a solution that someone should use when creating new shows.

    If you must play audio with video, follow Simon's statement and render them together as one file, verifying they are synced in post before loading them to the Catalyst.
    SourceChild
    TODD SCRUTCHFIELD

    ...if it ain't broke...
    gimme 5 and then don't act surprised

  6. #6
    Just found that running the audio from the same layer causes the playback to jitter and a 'spike' in the mov 1 play reading in the stats hud...

    Attached video: http://www.youtube.com/watch?v=wkmajfu0wdA

    This does not happen when using an non-audio play mode. I take it this could be a graphics card problem? Will look at replacing the cards tomorrow.

  7. #7
    Join Date
    Oct 2004
    Location
    UK - Milton Keynes
    Posts
    807
    possibly - but what are the specs of your movie?
    what codec and data rate - this could also be a factor?

    s
    Simon Pugsley

    SNP Productions Ltd. (UK)
    Lighting & Video Control Solutions
    Catalyst|Sales|Hire|Training|Support
    Catalyst Dealer UK Europe & Worldwide...

    Office: +44 (0)1908 410129
    Mobile: +44 (0)7958 390034
    simon@snp-productions.co.uk
    www.snp-productions.co.uk

  8. #8
    Just a note about the FPS counter and audio playback....

    I am currently doing a show through South America and we are running content that is 29.97.

    Yes, I am running content on Catalyst and no, I did not want 29.97 but we are also using the content on playback decks as well so 30fps was not an option.

    The content has to run frame accurate with the timecode of the show because the content was created exactly to the music of the set. In fact, we placed the music on the content as reference.

    Since the show timecode exceeds the total allowable length of time that a Catalyst frame counter can recognize, I have had to program the presets to be triggered from the SAM cuelist. Basically meaning the cuelist starts the file and then it free runs until the next SAM cue fades it out.

    I know this is a bit of a tangent but my point is simple.

    In order to make the files play frame accurate (roughly) to the timecode, I needed to use the audio playback mode because it will use the audio as a time base reference for playing the files.

    Yes, I drop frames this way and my whole team is aware of it. However, when the vocalist is shown in the content, lip syncing the same lyrics she's actually singing then the audience is more likely to notice voice slip than a few missed frames.

    Not the correct way to do things, but since day to day we might have 50hz or 60hz, power and PAL or NTSC, it's the only way to cover all bases.

    Take these thoughts as insight but try not to use this method if a better alternative is available.
    SourceChild
    TODD SCRUTCHFIELD

    ...if it ain't broke...
    gimme 5 and then don't act surprised

  9. #9
    Thank you both for your comments. In reply to Simon the mov specs are as attached...
    Attached Images Attached Images

  10. #10
    Ok, quick update. I have now installed Catalyst 4.40 onto two of my MacPro and my office i7 MacBook Pro and tried each with the file i am experiencing problems with.

    When playing the file in mode 70, all the macs play with a stutter so this narrows it down i guess to the way the video has been rendered in post..?

    Or i have three bad macs!

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