Digital Video

Areas of interest Desktop DV output technologies Desktop DV output technologies Software and hardware codecs Software and hardware codecs DVD output DVD output Video editing software systems Video editing software systems Simple DV capture Simple DV capture Professional non-linear editing (NLE) and DV capture Professional non-linear editing (NLE) and DV capture

Desktop DV output technologies Apple’s Quicktime is available on Macintosh, PC and other platforms Apple’s Quicktime is available on Macintosh, PC and other platforms This video player is known for good frame rates, reasonably good video quality and good file size This video player is known for good frame rates, reasonably good video quality and good file size Quicktime movies are “.mov” files Quicktime movies are “.mov” files QuickTime movie files can contain video images, animation and sound QuickTime movie files can contain video images, animation and sound

Desktop DV output technologies Microsoft’s Video for Windows is available on the Windows platform Microsoft’s Video for Windows is available on the Windows platform VfW files are in “.AVI” or “audio-video interleaved” format VfW files are in “.AVI” or “audio-video interleaved” format File size is moderate, quality is variable File size is moderate, quality is variable There are many different compressors available, causing compatibility problems There are many different compressors available, causing compatibility problems AVI’s have a 2GB file size limit AVI’s have a 2GB file size limit

Desktop DV output technologies MPEG (Motion Picture Experts Group) format, available on the Macintosh, PC and many others MPEG (Motion Picture Experts Group) format, available on the Macintosh, PC and many others MPEG movies are known for excellent compression with some blurring and blocky artefacts when over-compressed MPEG movies are known for excellent compression with some blurring and blocky artefacts when over-compressed MPEG movies are usually “.mpg” or “.mpeg” files MPEG movies are usually “.mpg” or “.mpeg” files MPEG1 is for desktop video MPEG1 is for desktop video MPEG2 is for broadcast-quality video and very low bit-rate video streams MPEG2 is for broadcast-quality video and very low bit-rate video streams

Desktop DV output technologies MJPEG (Motion JPEG) is a format widely used as an intermediate editable format MJPEG (Motion JPEG) is a format widely used as an intermediate editable format MPEG is quite lossy and gets great compression by interpolating frames, so it can be very hard to edit MPEG is quite lossy and gets great compression by interpolating frames, so it can be very hard to edit MJPEG individually compresses each frame with no reference to previous or following frames MJPEG individually compresses each frame with no reference to previous or following frames MJPEG compression is not so good, but it’s easy to edit any frame at any position within the movie MJPEG compression is not so good, but it’s easy to edit any frame at any position within the movie Most MJPEG movies are converted to another format (often MPEG) for publishing Most MJPEG movies are converted to another format (often MPEG) for publishing

Desktop DV output technologies Streaming Web-style (often extremely low bandwidth) media Streaming Web-style (often extremely low bandwidth) media Real Player, Real Video Real Player, Real Video Vivo Vivo MPEG MPEG Others Others Streaming data formats require noise immunity and drop-out tolerance, so they are often quite different to desktop video formats Streaming data formats require noise immunity and drop-out tolerance, so they are often quite different to desktop video formats

Software and hardware codecs Software codecs are common, often as plug-in library components Software codecs are common, often as plug-in library components For example, Video for Windows may use: For example, Video for Windows may use: Intel Indeo compression (versions 2, 3, 4 and 5) Intel Indeo compression (versions 2, 3, 4 and 5) Microsoft Video 1 format Microsoft Video 1 format Radius Cinepak (Mac- derived) Radius Cinepak (Mac- derived) RLE (run-length encoded) RLE (run-length encoded)

Hardware codecs Hardware to decode MPEG streams (in real time) is incorporated into DVD players Hardware to decode MPEG streams (in real time) is incorporated into DVD players MPEG decoder cards for PC’s are relatively inexpensive MPEG decoder cards for PC’s are relatively inexpensive MPEG encoder cards are more expensive MPEG encoder cards are more expensive Real-time MPEG2 encoders are relatively expensive (at around $2000 or £1300) Real-time MPEG2 encoders are relatively expensive (at around $2000 or £1300) Software codecs are many times slower than their hardware counterparts, but are correspondingly cheaper Software codecs are many times slower than their hardware counterparts, but are correspondingly cheaper

DVD output The acronym DVD has two parallel meanings: The acronym DVD has two parallel meanings: Digital Video Disc if the context is video Digital Video Disc if the context is video Otherwise it stands for Digital Versatile Disc (general mass storage, ROM or RAM) Otherwise it stands for Digital Versatile Disc (general mass storage, ROM or RAM) DVD can store about 5GB of movie data, allowing high quality video plus multiple soundtracks, text overlays and surround-sound information DVD can store about 5GB of movie data, allowing high quality video plus multiple soundtracks, text overlays and surround-sound information DVD requires some hardware acceleration for decoding and viewing DVD requires some hardware acceleration for decoding and viewing

Video editing software systems Popular editing software packages include: Adobe Premiere, Ulead Media Studio, IMSI Lumiere Video Studio Popular editing software packages include: Adobe Premiere, Ulead Media Studio, IMSI Lumiere Video Studio

Video editing software systems Video editing software has a common look: Video editing software has a common look:

Video editing software systems This is a snapshot from DigitalOrigin’s EditDV package This is a snapshot from DigitalOrigin’s EditDV package

Simple DV capture A minimal set-up requires an ordinary analogue video camera, a PC, a video digitiser card, some mass storage, plenty of RAM and lots of time A minimal set-up requires an ordinary analogue video camera, a PC, a video digitiser card, some mass storage, plenty of RAM and lots of time Raw data capture is feasible at low resolutions only – real-time compression is too expensive for most users Raw data capture is feasible at low resolutions only – real-time compression is too expensive for most users Low data transfer rate from video-capture hardware to disc storage prohibits high resolution capture Low data transfer rate from video-capture hardware to disc storage prohibits high resolution capture Video capture in video-conferencing resolutions is common with inexpensive digitisers Video capture in video-conferencing resolutions is common with inexpensive digitisers 352 by 288 pixels in 24-bit colour may be a sensible limit to work with (ITU standard res for VC) 352 by 288 pixels in 24-bit colour may be a sensible limit to work with (ITU standard res for VC)

Semi-professional DV capture The DV data rate (TV format) is approximately 3.6MB per second which consumes about 216MB of disk space per minute or about 13GB per hour The DV data rate (TV format) is approximately 3.6MB per second which consumes about 216MB of disk space per minute or about 13GB per hour Finished rendered movies take additional space beyond what your source clips consume Finished rendered movies take additional space beyond what your source clips consume Normal 20GB+ drives are readily available, but AV drives (with >4MB/sec sustained throughput) can be expensive Normal 20GB+ drives are readily available, but AV drives (with >4MB/sec sustained throughput) can be expensive Mid-range TV-quality DVE is affordable for small companies and individual producers Mid-range TV-quality DVE is affordable for small companies and individual producers

Semi-professional DV capture Current products (early 2000) combine hardware capture interfaces, based on 1394 FireWire, and software. They include: Current products (early 2000) combine hardware capture interfaces, based on 1394 FireWire, and software. They include: Digital Origin – EditDV (about $1000, £600) Pinnacle – miroDV200, DV300 ($600), DV500 ($900) Pinnacle – StudioDV (about $270, £170) Canopus – DVRex, DVRaptor Matrox – RT2000

Typical semi-professional DVE Provides nonlinear editing for digital video post production Provides nonlinear editing for digital video post production integrates compositing and keyframe animation integrates compositing and keyframe animation multi-track video and audio editing multi-track video and audio editing transitions (wipe, blend, cross-fade, iris etc.) transitions (wipe, blend, cross-fade, iris etc.) chroma-keying, luma-keying for overlays chroma-keying, luma-keying for overlays titling and character generation titling and character generation fast previews and interaction with the DV device fast previews and interaction with the DV device Captures source clips from DV tape Captures source clips from DV tape Trims source clips for use in a movie Trims source clips for use in a movie

Typical semi-professional DVE Assembles source clips into a sequential movie Assembles source clips into a sequential movie Adds transitions between clips Adds transitions between clips Applies filters to add special effects Applies filters to add special effects Layers multiple tracks of video for complex compositing effects Layers multiple tracks of video for complex compositing effects Has titling capabilities to create titles, credits and keys Has titling capabilities to create titles, credits and keys Animates objects with keyframing capabilities Animates objects with keyframing capabilities Renders effects at draft quality for rapid review Renders effects at draft quality for rapid review “Prints” movies to DV tape to create digital masters “Prints” movies to DV tape to create digital masters Exports digital movies in compressed computer format Exports digital movies in compressed computer format

Typical semi-professional DVE Digital video captures cleanly through a digital interface, no transcoding required Digital video captures cleanly through a digital interface, no transcoding required Analog video capture can impose many restrictions on the quality of the source data Analog video capture can impose many restrictions on the quality of the source data Less data manipulation means less image degradation Less data manipulation means less image degradation Images © Matrox Electronic Systems Ltd

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