Prototyping 2013-11-05 (Lens Based Media): Difference between revisions
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== Format == | == Format == | ||
* determines the way audio and video streams (and other metadata) are stored inside the file | * determines the way audio and video streams (and other metadata(like the codec info)) are stored inside the file | ||
* Examples are : | * Examples are : | ||
** .avi (Microsoft -> OLD) | ** .avi (Microsoft -> OLD) | ||
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** .ogg (Open Source -> but not very well supported by editing software) | ** .ogg (Open Source -> but not very well supported by editing software) | ||
** .mkv (Open Source -> but not very well supported by editing software) | ** .mkv (Open Source -> but not very well supported by editing software) | ||
** .mp4 (works on virtually all platforms) | ** .mp4 (works on virtually all platforms, browsers etc) | ||
== | [[file:interframe.gif|400px|right|thumb|intra- vs. interframe compression]] | ||
* '''Intraframe''' compression | |||
** Compresses each frame (with for instance JPG | == Encoding/Compressing == | ||
'''Why do we compress?''' | |||
* Image- and videofile sizes reduced | |||
* More files to store, or longer videos | |||
* Faster to download | |||
* Downside: someone has to decode! | |||
[[File:jpegcompression.png|thumb|right|400px|jpeg compression]] | |||
<br /> | |||
===Types of compression'=== | |||
* '''Intraframe''' or spatial compression | |||
** Compresses each frame (so similar to image compression, with for instance JPG) | |||
** No effective size compression | ** No effective size compression | ||
** High Quality | ** High Quality | ||
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** Apple ProRes, DNxHD (Avid) | ** Apple ProRes, DNxHD (Avid) | ||
* '''Interframe''' Compression | * '''Interframe''' or temporal Compression | ||
** Compress BETWEEN frames | ** Compress BETWEEN frames | ||
** effective size compression | ** effective size compression | ||
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** MPEG-2 (DVD's, hardware players), DivX (downloads), H264 (currently has best quality vs. file ratio) | ** MPEG-2 (DVD's, hardware players), DivX (downloads), H264 (currently has best quality vs. file ratio) | ||
<br> | <br> | ||
[http://en.wikipedia.org/wiki/Comparison_of_video_codecs comparison of video codec] | |||
=== encoding techniques === | |||
* Run length encoding > Looks for identical segments (often lossless) | |||
* [http://www.popmodernism.org/appropirate/delta.html Transform coding] > Most used (jpeg, DCT, wavelet) (selectively removes ‘non-relevant’ detail from the image). | |||
* [http://www.knotless.com/1/post/2012/07/the-mysteries-of-chroma-sub-sampling.html Chroma subsampling] >Selective loss of resolution (4:4:4 vs 4:2:0) | |||
* Reducing bit-depth (reducing colour accuracy) | |||
* Fractal compression (replacing pixels with mathematic approximations) | |||
[[file:iframes.jpg|400px]] | |||
[http://www.axis.com/products/video/about_networkvideo/compression.htm More Info]<br/> | |||
[http://www.youtube.com/watch?v=ShG1mnHKntg&t=2m2s] <br/> | |||
== Tools == | == Encoding Tools == | ||
* ffmpeg (ffmpegX for a Mac gui version) | * [http://www.ffmpeg.org/download.html ffmpeg (ffmpegX for a Mac gui version)] | ||
* Mencoder | * [http://en.wikipedia.org/wiki/MEncoder Mencoder] | ||
* Handbrake | * [http://handbrake.fr/ Handbrake] | ||
* Mpegstreamclip | * [http://www.squared5.com/ Mpegstreamclip] | ||
* Adobe Media Encoder | * Adobe Media Encoder | ||
== Bitrate + Framesize == | |||
== Workflow & Delivery == | Most lossy codecs allow you to set a [http://neuron2.net/LVG/ratesandsizes.html bitrate] (the amount of bits per second) | ||
<br>Together with the framesize this determines the quality of the video. | |||
[http://floppyfilms.pleintekst.nl/oscars_2009/slumdog/ Floppy Films] | |||
== Workflow, Archiving & Delivery == | |||
* | There's no solution to the question 'What is the best setting for my video?". All depends on the platform you will deliver to! | ||
* How do you record? (Camera codec? DSLR) | |||
* How do you edit? (intermediate files?) | |||
* What do you deliver? (Archiving, uploading, DVD?) | |||
<br > | |||
Example, '''for editing/archiving use''': | |||
* ProRes video codec (visually lossless through many iterations) | |||
* Wav/Aiff audio codec | |||
* .mov container | |||
'''For (online) delivery use''': | |||
* H.264 codec | |||
* MP3/ACC audio codec | |||
* .mp4 container | |||
<br> | |||
* [http://mashable.com/2010/06/03/youtube-i-am-sitting/ what happens when you upload to youtube?] | |||
== | == Glitch Art & Data moshing == | ||
[[File:downloadfinished.jpg|right|thumb|400px|Download Finished]] | [[File:downloadfinished.jpg|right|thumb|400px|Download Finished]] | ||
* [http://www.youtube.com/watch?v=tYytVzbPky8 | * [http://www.youtube.com/watch?v=tYytVzbPky8 How to datamosh] | ||
* [http://www.download-finished.com/ | * [http://www.download-finished.com/ Download Finished] by [http://wwwwwwwwwwwwwwwwwwwwww.bitnik.org/d/| Mediengruppe Bitnik] | ||
* [http://snorpey.github.io/jpg-glitch/ | * [http://snorpey.github.io/jpg-glitch/ glitch your image, source code] | ||
{{#ev:youtube|mvqakws0CeU?version=3&autohide=1&showinfo=0}} | {{#ev:youtube|mvqakws0CeU?version=3&autohide=1&showinfo=0}} |
Latest revision as of 10:43, 5 November 2013
Compression & Codecs in video
(File)Format or Container is the shipping box, codec is the goods inside the box.
Format
- determines the way audio and video streams (and other metadata(like the codec info)) are stored inside the file
- Examples are :
- .avi (Microsoft -> OLD)
- .wmf (Microsoft -> Unflexible)
- .mov (Apple -> supports a lot of codecs)
- .ogg (Open Source -> but not very well supported by editing software)
- .mkv (Open Source -> but not very well supported by editing software)
- .mp4 (works on virtually all platforms, browsers etc)
Encoding/Compressing
Why do we compress?
- Image- and videofile sizes reduced
- More files to store, or longer videos
- Faster to download
- Downside: someone has to decode!
Types of compression'
- Intraframe or spatial compression
- Compresses each frame (so similar to image compression, with for instance JPG)
- No effective size compression
- High Quality
- Easily readable by edit software
- Apple ProRes, DNxHD (Avid)
- Interframe or temporal Compression
- Compress BETWEEN frames
- effective size compression
- Not easy for edit software
- Use for sharing -> final output
- MPEG-2 (DVD's, hardware players), DivX (downloads), H264 (currently has best quality vs. file ratio)
encoding techniques
- Run length encoding > Looks for identical segments (often lossless)
- Transform coding > Most used (jpeg, DCT, wavelet) (selectively removes ‘non-relevant’ detail from the image).
- Chroma subsampling >Selective loss of resolution (4:4:4 vs 4:2:0)
- Reducing bit-depth (reducing colour accuracy)
- Fractal compression (replacing pixels with mathematic approximations)
Encoding Tools
- ffmpeg (ffmpegX for a Mac gui version)
- Mencoder
- Handbrake
- Mpegstreamclip
- Adobe Media Encoder
Bitrate + Framesize
Most lossy codecs allow you to set a bitrate (the amount of bits per second)
Together with the framesize this determines the quality of the video.
Floppy Films
Workflow, Archiving & Delivery
There's no solution to the question 'What is the best setting for my video?". All depends on the platform you will deliver to!
- How do you record? (Camera codec? DSLR)
- How do you edit? (intermediate files?)
- What do you deliver? (Archiving, uploading, DVD?)
Example, for editing/archiving use:
- ProRes video codec (visually lossless through many iterations)
- Wav/Aiff audio codec
- .mov container
For (online) delivery use:
- H.264 codec
- MP3/ACC audio codec
- .mp4 container
Glitch Art & Data moshing
{{#ev:youtube|mvqakws0CeU?version=3&autohide=1&showinfo=0}}