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Why is sound lost when I trim my mpg?

Hello community! I lose sound when I attempt to trim dead space from the beginning of my mpg. I have tried trimming using Select All Excluding Silence and by dragging the trim bar. Both result in an mpg with intermittent sound. Any suggestions?

Mac OS X (10.6.8)

Posted on Aug 3, 2012 10:32 AM

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5 replies

Aug 3, 2012 2:46 PM in response to WindriftDeeDee

Any tips for coverting?

I think what Gary means to say is that "muxed" content consists of blocks of audio data interspersed with blocks of video data. As such, there is no one-to-one relationship between a given frame of video data and what would be a corresponding frame of audio data. (I.e., QT conversion compatible content consists of parallel tracks of data in which each frame of video data is temporally synchronized with a corresponding frame of audio date via a common clock.)


The normal approach here would, depending on the specific data compression in the MPG file, be to use a third-party app to perform the conversions. For instance, if the "muxed" source file contains MPEG-1 video, you can use the free MPEG Streamclip to convert the content to any compression format combination for which your system is codec component configured. (The same app will also convert "muxed" MPEG-2 content but requires you to purchase and install the QT MPEG-2 Playback component from Apple.) On the other hand, "muxed" MPEG-2 content can be converted to H.264/AAC or MPEG-4/AAC content using the free HandBrake app. (I.e., the QT MPEG-2 Playback component is not required here but your choice for output compression formats is limited to the codecs supported by HandBrake.)


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Why is sound lost when I trim my mpg?

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