MPEG Streamclip export. Audio not synced.

Discussion in 'Digital Video' started by Luckyword, Nov 1, 2009.

  1. Luckyword macrumors newbie

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    Jul 4, 2008
    #1
    I have a ReplayTV (similar to Tivo), and use mReplay to download TV shows to my mac. I downloaded a show, and want to edit it. It downloads as quicktime file, but I can't edit the file when I open it in Quicktime. The little edit arrows are not there. So I import it into MPEG Streamclip, edit the clip, and then export it. But the audio is not synced with the video. I've played around with it quite a bit and can't figure out what I'm doing wrong. On the export, the settings I am using are: Export to MPEG-4, Compression is Apple MPEG4 Compressor, frame size is 720 x 480 (DV-NTSC). I've tried limiting the Frame Rate and Data Rate but that doesn't solve the problem. Any ideas on why it's doing this, and how I can solve this problem. Please help. Thanks for your consideration. Davi
     
  2. spinnerlys Guest

    spinnerlys

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    #2
    What kind of edits do you make?

    How much out of synch is the audio?

    Have you looked at iMovie?

    Are the files copyright protected and use some kind of DRM (Digital Rights Management)? That could explain the inability to trim in QuickTime Pro.
     
  3. Luckyword thread starter macrumors newbie

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    #3
    Response

    Thanks for the reply.

    I'm trying to cut some off at the beginning, and some off at the end.

    IMovie won't import it for some reason.

    It is an MPEG file.

    I can't tell if it's copy protected.
     
  4. spinnerlys Guest

    spinnerlys

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    #4
    You could convert the source file to a DV stream with the help of MPEG Streamclip, and then properly cut off the start and end with iMovie.

    Do you have QT Pro?
     
  5. Luckyword thread starter macrumors newbie

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    #5
    QT Pro and DV

    Thanks.

    I'm trying the DV Convert right now. I'll post again if that doesn't work. Thanks. :)
     
  6. Luckyword thread starter macrumors newbie

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    #6
    Converting worked, but...

    It did work. The quality doesn't seem to be that great though, and one problem is that the picture is cut off on the right and left side of the screen. I used the 4:3 Aspect Ratio, which seems to be what my TV uses.

    Any other suggestions? :)
     
  7. bmcgonag macrumors 65816

    bmcgonag

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    #7
    Normally when I use MPEGStreamClip (MSC) it auto recognizes the aspect ratio. Are you adjusting it manually to be 4:3?

    This will cut off the ends if it is a native 16:9 show or movie. Even if you tv is 4:3.

    Not sure if that helps.

    Also, in iMovie, when you export, I believe you can select SD or HD, and SD should give a more TV 4:3 look, rather than a Computer 4:3.

    I believe that for computers 4:3 is 640x480 where as TVs are more like 754x5xx something.

    I could be wrong, but it seems that was the case...it's been a while.
     
  8. spinnerlys Guest

    spinnerlys

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    #8
    PAL and NTSC (both broadcast systems for SD content) use 4:3 (and also 16:9 in the last decade) as ratio for displaying its content. It came from the early years of cinema, which also used 4:3, but changed to wider aspect ratios (up to 4:1 for Napoleon, filmed with four parallel cameras) to differentiate itself from TV and get people to go to cinemas due to it's more attractive format (our eyes don't view the world in 4:3).

    PAL uses 625 lines for creating images, which resulted in two pixel resolutions. 768x576 for proper SD content, 720x576 for DV encoded material, as DV has an pixel aspect ratio of 1.0666666).

    NTSC uses 525 lines and results in 640x480 images for computers, it's 720x480 for DV NTSC footage.

    Computer monitors were modeled after TVs, using the Cathode Ray Tube (CRT) to create images, so 4:3 was used for computer monitors too.

    Just with the advent of flat screen display, wider aspect ratios like 16:10 or even 16:9 became more common on computer monitors.


    To the OP: As it was said before, check the aspect ratio of the source file and apply it to the file you want it to encode to.

    [​IMG]
     
  9. Luckyword thread starter macrumors newbie

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    Jul 4, 2008
    #9
    Will Try Again

    I'll try again. I'm not changing the settings or anything. But geez, I wish there were a way around this. WHen I export using DV, there is a quality degradation. But, again, when I use the Export to to MPEG-4, the audio is not synced. Does anyone know of a solution for this? Or, if I do export using DV, what are the optimal settings? Is it better to use DV25, DVPRO25, or DVPRO50? When I use DV25, I noticed a considerable degradation once I imported it into IMOvie, then exported it again. Is there a way around all this?
     
  10. bmcgonag macrumors 65816

    bmcgonag

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    #10
    Have you looked at the .dv file in a player before importing and re-exporting?

    I know others have complained that iMovie itself seemed to cause the degredation.
     
  11. spinnerlys Guest

    spinnerlys

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    #11
    DV25 should be sufficient, as the source is more compressed.
    The source will use MPEG-2 or MPEG-4, which only saves group of pictures (GOP) - meaning not every frame is stored in a video, and DV saves every frame of a video.

    What codec did you use for exporting it from iMovie?


    And did you use PAL or NTSC for DV export in MPEG-Streamclip? And did you use PAL or NTSC as a setting in iMovie?
     

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