title: Fastest way to encode a frame twice (duplicate, h264 format) using JavaCV ffmpeg?
body: <p>I want to join-encode several videos with different frame rates in the same output video with constant frame rate using FFmpegFrameRecorder, as fast as possible. I am thinking to duplicate frames in case I want to increase frame rate, and skip frames when I need to decrease frame rate. I am using JavaCV. </p>
  
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  <p>Is there any better way of duplicating frames except for calling record(image) twice? (the output is always h264 stored in mp4 file format) Something like a flag in h264 stream indicating that current frame is a duplicate of last one, or something else to skip the redundant encoding.</p>