My car has an onboard video recorder that captures video onto an SD card containing the resulting MP4 files. My iMac can read the mp4 file and play back sound and video fine with VLC app. However, when i import the MP4 file into iMovie to edit, the video comes in fine, but sound is gone. How do I get sound working? CODEC? File Conversion? Please advise
iMac, OS X El Capitan (10.11.1), source 2016 Corvette Z06 PDR on SD
Hi,
Not all Mp4 vids are compatible with iMovie. iMovie needs Mp4/H.264/AAC. AAC stands for Advanced Audio Codec, and if your movie contains some other audio codec that might cause the audio not to play. Further, some Mp4 buckets contain other codecs that cause iMovie not to accept it.
Open your movie with Quicktime and, in the Quicktime menu, select Window and then select Show Movie Inspector. You will get an information box that will tell you what codec is used in the movie. If it doesn't comply with the above, try converting it to Mp4 with the free download Handbrake or MPEG Streamclip, or to a Quicktime Movie (.mov) with MPEG Streamclip. See if that cures the absence of audio.
And, to cover all the bases, check your iMovie audio settings to make sure that you haven't inadvertently muted the audio. Does the video clip show audio waveforms?
To make sure that there isn't some iMovie preferences corruption causing the misbehavior, try restarting your computer and launching iMovie while holding down the Option and Command keys, and then selecting to delete preferences in the box that appears.
Another thing you can do is to rule out that the problem isn't related to your current project. Create a new project and import your video into it, and see if the audio plays.
Hope this helps.
-- Rich
Hi,
Not all Mp4 vids are compatible with iMovie. iMovie needs Mp4/H.264/AAC. AAC stands for Advanced Audio Codec, and if your movie contains some other audio codec that might cause the audio not to play. Further, some Mp4 buckets contain other codecs that cause iMovie not to accept it.
Open your movie with Quicktime and, in the Quicktime menu, select Window and then select Show Movie Inspector. You will get an information box that will tell you what codec is used in the movie. If it doesn't comply with the above, try converting it to Mp4 with the free download Handbrake or MPEG Streamclip, or to a Quicktime Movie (.mov) with MPEG Streamclip. See if that cures the absence of audio.
And, to cover all the bases, check your iMovie audio settings to make sure that you haven't inadvertently muted the audio. Does the video clip show audio waveforms?
To make sure that there isn't some iMovie preferences corruption causing the misbehavior, try restarting your computer and launching iMovie while holding down the Option and Command keys, and then selecting to delete preferences in the box that appears.
Another thing you can do is to rule out that the problem isn't related to your current project. Create a new project and import your video into it, and see if the audio plays.
Hope this helps.
-- Rich
Rich839, you are the man. Solution confirmed. The AAC codec was missing. I downloaded HandBrake, converted to a new MP4 file (it added the codec by default). and DONE! Thanks for the tip.
Original source: Corvette Performance Data Recorder on SD Card as an MP4. Post conversion with HandBrake, also an MP4 file. Used new MP4 file as import to iMovie and both Video and Sound work perfectly. Now off to go editiing!
Great! Glad it worked for you.
iMovie import of an MP4 will no play sound?
