Compressing Videos With MPEG Streamclip
Perhaps the most useful function of MPEG Streamclip is its compression capabilities. Sometimes you want to share a video with a friend using Dropbox, a data DVD, or a video sharing website, but the file is too large and not compressed for the sharing method you prefer. MPEG Streamclip lets you adjust the codec, frame rate, bitrate, and aspect ratio.
The Exporter Window
The compression options you have depend on the file type you’re compressing to. The Quicktime, MPEG-4, and AVI compressors use similar exporting controls aside from the Compression types at the top of the exporter box. The MPEG-4 exporter only allows for H.264 and Apple MPEG4 compressors because these are the only compressors accommodated by this file type. Quicktime, MPEG-4, and AVI include a wide range of compressors—both open source and proprietary—so you’ll most likely find what you’re looking for when working in these formats. If you’re compressing your video to make it smaller for sharing purposes, use H.264 for compression, regardless of the file format you choose. After you choose the compressor for your video, you’ll be able to adjust the Quality with a simple toggle interface that ranges from 0 percent to 100 percent. Right below this slider, you’ll see a box that allows you to limit the data rate of your video. This feature is useful as MPEG Streamclip will calculate the estimated size of your output file once you choose a bit rate. Standard bit rates for SD video are 2,000-5,000 kbps, and standard bit rates for HD video are 5,000-10,000 kbps, depending on the frame rate of your video. After you enter a value, you’ll see an estimated file size appear to the right. This indicator lets you know if your exported file will be small enough for your sharing method.
Frame Rate, Blending, Downscaling, and More
Next, choose a frame rate for your video. Match this to the frame rate of your original file unless you shot at a very high frame rate, in which case dividing this number will make your file size smaller. Then, choose frame blending and better downscaling if there’s an inconsistency between your chosen frame rate and the frame rate of your original video—this tweaking maximizes the quality of your exported file. If your video is interlaced—i.e. the frame rate is 29.97 or 59.94 fps—choose Interlaced Scaling. If you shot progressive—i.e. 24, 30 or 60 fps—un-check this box. Select the Make button at the bottom of the Exporter window, and you’ll see a preview window with a time bar that shows you the progress of your export. Save the export and choose a filename that differs from the original video, like video.1 or video.small.
