Video File Formats - MP4, MOV, MKV

Techquickie ·Techquickie ·2019-05-06 · 1,123 words · ~5 min read
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0:00 thanks for watching techwiki click the subscribe button then enable
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0:07 comes to video files there are a lot of
0:10 file formats out there if you're a video editor or a media enthusiast you've
0:14 probably encountered a veritable alphabet soup of different ones so just
0:18 like in our episodes on audio and image formats which you can check out up here
0:23 we're going to demystify some of the common formats that you can choose for
0:27 your newfangled moving picture movies
0:30 first up to avoid confusion it's important to keep in mind that the
0:34 extension you see at the end of a file name such as mp4 or mkv or mov
0:40 actually specifies what kind of container the file is in but there's
0:44 more to formats than just the container so all those video clips and trailers
0:48 that you got could be using any number of different codecs as well
0:52 but what's a codec glad you asked most digital video is
0:57 compressed in some way since otherwise it'd take up tons of space on your hard
1:01 drive a codec is simply a particular scheme that's used to compress or
1:06 decompress a file there are lots of codecs out there but
1:10 one of the most prevalent ones today is h.264 which is popular because it
1:15 retains decent image quality while shrinking the file sizes significantly
1:21 the way it works is by instead of saving each frame of the video pixel by pixel
1:26 h.264 splits frames into blocks of 256
1:30 pixels each and tries to predict what each subsequent block will look
1:35 like based on either the rest of the frame or from previous frames the
1:40 algorithm then compares the predicted block to the actual block creating a
1:45 difference called a residual next the kodak compares the residual to 16
1:50 checkerboard-like standard patterns and how much of each pattern contributes to
1:54 the residual is stored as a number with higher frequency patterns you see to the
1:58 lower right often discarded as these
2:01 take up the most space this is really similar to how jpeg works for still
2:06 images and like jpeg you can choose how
2:09 much compression you want with higher compression discarding more patterns and
2:14 yielding smaller file sizes but also
2:17 lower quality however h.264 is actually pretty good at
2:21 making predictions and even includes a filter to reduce some of the compression
2:25 blockiness you sometimes see on low quality video making it a standard go-to
2:31 codec for sites like youtube as well as for blu-ray discs at similar visual
2:36 quality h.264 only takes up about half as much space as mpeg-2 which is still
2:41 in use today for dvd video and broadcast tv but a new codec the imaginatively
2:47 named h.265 better known as hevc is even
2:50 more efficient than h.264 it can use blocks of up to
2:54 4096 pixels and has more advanced prediction algorithms which is critical
2:59 for keeping file sizes manageable as internet streaming continues
3:03 on its inevitable march towards 8k
3:06 of course one downside to both h.264 and
3:10 265 is that they're protected by patents
3:13 so companies that want to use these codecs have to pay royalties that seems
3:17 to be the motivation behind the development of vp8 and vp9 a pair of
3:23 open source standards being pushed by google that are technologically quite
3:27 similar to hevc there are image quality
3:30 differences but there's no real consensus as to which one is better so
3:34 some service providers like netflix just use whichever codec will work best on
3:39 the device the user's watching from there are other codecs floating around
3:42 there like the venerable avi but at this
3:45 point we've covered the major modern ones so let's get back to container
3:50 files starting with the familiar mp4 mp4
3:54 enjoys wide compatibility and can hold either an mpeg or an h.264 encoded video
4:00 along with an aac or mp3 audio stream
4:04 pro tip if you ever see m4v
4:07 at the end of a video it's basically just a version of mp4 with drm enabled
4:12 so if one of these files refuses to play try simply changing the extension to mp4
4:16 and give it another go but although mp4 is still really popular especially among
4:20 youtubers the matraska or mkv container
4:24 is one of the fastest growing it can support just about any combination of
4:28 audio and video codecs including newer ones like h.265 and has more flexible
4:33 support for menus and chapters as well as the ability to play back a corrupted
4:37 file so you won't necessarily lose all of that super important drone footage of
4:42 your boring neighborhood and for creative types there are many other
4:46 formats that you might encounter each with their own advantages and drawbacks
4:51 for example the mov format which was developed by apple for quicktime
4:55 supports multiple codecs and is easier to edit on the fly without having to
5:00 rewrite the entire file when you're done a cool feature that makes exporting a
5:05 finished video from final cut much faster than competing video editors that
5:09 have to encode the entire project from scratch finally we can't wrap this video
5:14 up without talking about flv and f4 v these indicate of course that the clip
5:19 is meant to be played in adobe flash which is being phased out
5:25 now you know i'd love to tell you all about that but we're out of time so go
5:28 and watch the video that we already made about it and be sure to yell at us down
5:33 in the comments if we neglected the file video format of your choice
5:37 juggling multiple computers is difficult you end up with various sets of mice and
5:41 keyboards on your desk which not only looks messy but gets super confusing kvm
5:46 switches can partially solve this problem but we found that they aren't
5:49 very seamless and are sometimes cumbersome but with synergy you can move
5:53 the mouse seamlessly between your computers which makes them feel like one
5:56 computer check out the full details at the link below so thanks for watching
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