[0:01] [Music]
[0:12] welcome to another video from explaining
[0:14] computers
[0:17] this time i'm going to talk about
[0:19] digital video
[0:20] formats to do this i also need to
[0:23] explain
[0:23] digital video codecs and containers
[0:27] so let's go and get started
[0:35] digital video files can have many
[0:38] different file extensions
[0:40] including mp4 mov and
[0:43] mxf however the first thing to
[0:46] understand about digital video formats
[0:48] is that they're not defined by their
[0:50] file type
[0:51] this makes digital video formats far
[0:54] more complex than for example
[0:56] image formats where you can be certain
[0:58] that a jpg
[0:59] file is an image in the jpeg format
[1:04] rather than being defined by a file type
[1:06] a digital video format
[1:08] is a combination of a video codec and a
[1:10] container
[1:12] codec stands for coder decoder and
[1:15] refers to the algorithm used to
[1:17] digitally encode a video
[1:20] meanwhile a container is a digital box
[1:22] or wrapper
[1:23] used to store video streams in related
[1:25] content in a single
[1:26] file it is therefore digital video
[1:29] containers that can be identified by
[1:31] their file extension
[1:33] and not digital video formats
[1:37] today the great many video codecs and
[1:39] containers are in use
[1:40] with common codecs including h.264
[1:44] also known as avc h.265
[1:47] also known as hevc h.262
[1:50] also known as mpeg-2 part 2 mjpeg
[1:54] prores dnxhd and dnxhr
[1:59] common containers include mp4 avi
[2:03] mov mxf 3gp and 3g2
[2:07] and mts m2ts and ts
[2:10] there are many other digital video
[2:12] codecs and containers
[2:14] but the ones listed are those i'll
[2:15] explain in more detail
[2:17] later in this video
[2:21] as you probably gathered digital video
[2:23] is complex
[2:24] and can get somewhat confusing so
[2:28] to help us get our heads around the
[2:29] critical concept the video format being
[2:32] a combination of a codec
[2:34] and a container let's take a look at one
[2:36] of these
[2:37] a mini dv tape which was for years a
[2:40] common means of storing
[2:41] digital video however a minidv
[2:45] tape is a container and not a format as
[2:48] it can be used to store video
[2:49] in three different ways specifically a
[2:52] minidv
[2:53] tape like this one can store video
[2:55] encoded with the standard definition
[2:57] consumer dv
[2:58] codec with a professional standard
[3:00] definition codec called
[3:02] dv cam and with a high definition codec
[3:05] called hdv this means that it's
[3:08] impossible to look at the dv
[3:10] tape like this and to know its format
[3:13] and precisely the same is true when it
[3:15] comes to digital video
[3:17] files where the file extension indicates
[3:19] the container
[3:20] but not the videos codec
[3:29] digital video just like a reel of movie
[3:31] film
[3:32] is made up of a series of still frames
[3:35] a codec or coder decoder digitally
[3:38] encodes these frames
[3:40] with the term codec used to refer to
[3:42] both the software or hardware
[3:44] that performs the encoding operation as
[3:46] well as the algorithm
[3:47] it applies because videos contain a
[3:51] great deal of information
[3:52] most but not all codecs compress a
[3:55] video's frames
[3:56] to limit file size such compression can
[3:59] also
[4:00] be achieved in two ways known as
[4:02] intra-frame
[4:03] and interframe intra-frame compression
[4:07] compresses each frame individually in
[4:10] contrast
[4:11] inter-frame compression stores some
[4:13] complete frames as keyframes
[4:15] but all frames in between as delta
[4:17] frames which only contain
[4:18] incremental changes this allows
[4:21] interframe compression
[4:22] to produce smaller video files however
[4:26] intra-frame video is generally of a
[4:28] higher quality
[4:29] and is easier for a computer to edit as
[4:31] every frame is immediately accessible
[4:34] so if you are planning to edit your
[4:36] video it's best to shoot it using an
[4:38] intra-frame codec if possible
[4:42] common intra-frame codecs include mjpeg
[4:46] prores dnxhd and dnxhr
[4:50] as you may guess mjpeg stands for motion
[4:53] jpeg
[4:54] and stores each video frame or field as
[4:57] an individual jpeg image
[4:59] prores is a family of intraframe codecs
[5:02] created by
[5:03] apple which is widely used in
[5:05] professional video acquisition
[5:06] and production for different codecs in
[5:09] the prores family are named prores 422
[5:12] proxy which has the lowest data rate and
[5:14] quality
[5:15] up to prores 444xq which has a very high
[5:19] data rate
[5:20] and produces very large files
[5:24] dnxhd stands for digital non-linear
[5:27] extensible high definition and is a
[5:30] family of intra-frame codecs
[5:31] created by avid for professional video
[5:33] editing but now also used for
[5:35] acquisition
[5:37] as you may guess dnxhr is a higher
[5:40] resolution
[5:41] version of dnxhd supporting 4k video
[5:44] and above in common with prores dnxhd
[5:48] and dnxhr data rates and file sizes can
[5:51] get very large
[5:53] indeed
[5:56] one of the most popular codecs in use
[5:58] today is h.264
[6:00] also known as avc or advanced video
[6:03] coding
[6:04] h.264 was defined by the motion picture
[6:07] experts group
[6:08] or mpeg in part 10 of their standard
[6:11] mpeg-4
[6:14] most of the time h.264 is an interframe
[6:17] codec
[6:18] that produces relatively small video
[6:20] files by storing keyframes
[6:22] and the incremental differences between
[6:24] them however
[6:25] the specification allows h.264 to be
[6:28] used
[6:28] as an intra-frame codec and some
[6:30] professional video formats take
[6:32] advantage of this
[6:33] usually describing their codec as iframe
[6:36] h264
[6:40] a more recent and increasingly popular
[6:42] interframe codec
[6:43] is h.265 also known as hevc
[6:47] or high efficiency video coding this was
[6:50] also defined by the motion picture
[6:52] experts group
[6:53] in part two of their standard mpeg-h and
[6:56] can produce video with the same quality
[6:58] as an interframe h.264 codec
[7:00] with roughly half the data rate and file
[7:02] size
[7:04] however h.265 requires more computer
[7:07] power to encode and decode with h.264
[7:10] and so is not as easy to edit
[7:15] an earlier and still very important
[7:17] interframe codec
[7:18] is h.262 which was defined by the motion
[7:21] picture experts group
[7:23] in part two of their mpeg-2 standard
[7:26] h.262 is not as efficient as h.264
[7:30] or h.265 so produces much larger video
[7:34] files however it is still widely used
[7:37] for standard definition digital
[7:39] television broadcasts
[7:40] and dvds
[7:48] as noted earlier a digital video format
[7:51] is a combination of a video codec and a
[7:54] container
[7:55] here a container is a digital box or
[7:58] wrapper
[7:58] that is used to store a video stream as
[8:01] well as one or more accompanying audio
[8:03] streams
[8:03] and potentially other related content
[8:05] such as subtitles
[8:07] and metadata digital video containers
[8:11] include mp4 avi and
[8:14] mov mp4 was defined by the motion
[8:18] picture experts group
[8:19] in their mpeg-4 part 14 specification
[8:23] avi was developed by microsoft and
[8:26] stands for audio video into leave
[8:28] and mav was created by apple and is
[8:30] short for movie
[8:32] all three of these containers can store
[8:34] video encoded with many different codecs
[8:37] with mp4 and mov currently having the
[8:40] widest
[8:40] range of both professional and consumer
[8:43] applications
[8:45] more niche containers include mxf 3gp
[8:49] and 3g2 as well as mts m2ts
[8:53] and ts mxf stands for material exchange
[8:58] format
[8:58] and is a container used in professional
[9:00] video production and distribution
[9:03] meanwhile 3gp and 3g2 are containers
[9:07] developed by the third generation
[9:08] partnership project
[9:10] for use on mobile phones finally
[9:13] mts m2ts and ts
[9:16] were created for the avchd video format
[9:19] and blu-ray discs and stand for mpeg
[9:22] transport stream
[9:23] and peg 2 transport stream and transport
[9:26] stream
[9:26] respectively
[9:33] the codecs and containers we've just
[9:35] looked at can be combined
[9:37] to create a wide variety of video
[9:39] formats some of which
[9:40] are mainly used for recording and others
[9:42] for the delivery of final video files
[9:46] to provide just a few examples when it
[9:48] comes to acquisition
[9:50] videos recorded in the still relatively
[9:52] popular consumer format
[9:53] avchd which stands for advanced video
[9:57] coding high definition
[9:58] use the h.264 codec and either an mts
[10:02] or m2ts container the xavc-i
[10:06] and xavcl formats used on many sony
[10:09] cameras then store h.264 video in an mxf
[10:13] container
[10:13] while the closely related xavcs format
[10:17] uses an h.264 codec and an mp4 container
[10:21] many canon cameras shoot in a format
[10:23] called xfavc
[10:25] which again uses the h.264 codec and an
[10:27] mxf container
[10:30] often especially in the consumer arena
[10:33] video formats are not given a name
[10:36] for example most dslrs do not declare a
[10:39] format
[10:40] but use an h.264 or h.265 codec
[10:43] with either an mp4 or mov container
[10:47] similarly video captured on cameras and
[10:49] recorders that use a prores codec
[10:51] is typically described as being in the
[10:54] prores format
[10:55] and stored in a mod container whilst
[10:58] dnxhd
[10:59] and dnxhr codec videos are usually
[11:02] placed in either an fxf
[11:03] or mov file videos shot on smartphones
[11:08] also don't have a named format but are
[11:10] usually encoded with an h264 or h.265
[11:14] codec
[11:15] and stored in a 3gp 3g2
[11:18] or mp4 container on an android device or
[11:21] in a mav container
[11:22] on an iphone
[11:25] when it comes to the delivery of final
[11:27] digital video files
[11:29] once again we often lack specific format
[11:32] names
[11:32] although h264 and h.265 codex
[11:36] used with mp4 or mov containers are the
[11:39] most common
[11:40] in the consumer space and if you are
[11:43] ever in doubt
[11:44] render your final video using the h.264
[11:47] codec
[11:48] and an mp4 container as this is always a
[11:50] very safe bet
[11:52] as well as being the recommended upload
[11:54] format for youtube
[11:57] the professional delivery of final video
[12:00] files
[12:00] usually takes place in an mxf container
[12:03] using codecs that include prores dnxhd
[12:07] and dnxhr this said
[12:10] an intra-frame panasonic codec called
[12:13] avc
[12:13] intra is also very common
[12:17] indeed in october 2014 all uk
[12:20] broadcasters began using a format called
[12:22] as11dp for hd program delivery
[12:26] which uses the avc intra codec and an
[12:29] mxf container
[12:32] finally most cinemas these days project
[12:35] from a format
[12:36] called digital cinema package or dcp
[12:40] this uses an mjpeg codec and an mxf
[12:43] container
[12:44] so the mjpeg codec is not as rare
[12:48] as you may have imagined
[12:56] for the best part of a century the most
[12:58] stable and widespread motion picture
[13:01] format
[13:01] was this 35 millimeter film now
[13:06] technically we could argue that even the
[13:07] role of 35 millimeter film
[13:09] is a container and not a format because
[13:12] the
[13:12] frames on a roll of 35 millimeter film
[13:15] can be
[13:16] optically stretched to accommodate
[13:18] different aspect ratios and
[13:20] the vista vision format shot 35
[13:22] millimeter film
[13:23] horizontally and not vertically in order
[13:25] to get a bigger frame with higher
[13:27] resolution but for the most part
[13:30] for the best part of about a hundred
[13:32] years if you wanted to shoot
[13:34] high quality moving images with a good
[13:36] archive potential
[13:37] you chose the 35 millimeter film format
[13:41] today digital video reigns supreme
[13:45] online on television and in the cinema
[13:48] and as we've seen in this video there
[13:50] are a wide range of codecs and
[13:52] containers available
[13:54] which give us a bewildering array of
[13:56] digital video formats
[13:59] and deciding which one to shoot in to
[14:02] edit in to deliver in
[14:03] and to archive in is a very tricky
[14:06] decision
[14:07] but i hope at least in this video i've
[14:08] given you some useful
[14:10] information but now
[14:13] that's it from me and the role of 35
[14:15] millimeter film
[14:17] if you've enjoyed what you've seen here
[14:18] please press that like button if you
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[14:21] please subscribe and i hope to talk to
[14:23] you again
[14:25] very recent
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[14:42] you