Video: Difference between revisions

Revision as of 10:29, 1 December 2011

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History

A brief history of online video

1990s QuickTime, Windows Media, RealPlayer
2002 Flash (Player 6: Spark)
2005 Flash (Player 8: On2 VP6)

Culture Shift / Patent Wars

Media formats have consistently been at the intersection of legal & social battles reflective of the impact of digital media on an established music and film industry.

Link to "new oil" site of Seb Luetgert

Terminology

Terminology: Container

The container is the "box" that holds the video file. Containers organize how the audio/video data is "laid out" as a "byte stream" (thus may have an impact on how well a video can "stream" or appear in the browser when only partially downloaded). Container formats may also allow for "metadata" to be included (name-value pairs of data such as the artist name of a music track).

Examples:

MOV (Apple/QuickTime)
MP4 (MPEG)
WMV (Microsoft/Windows)
FLV (Flash Video)
AVI ("audio-video interleave": Microsoft)
MKV (Matroska, Free software, basis of WebM, Implemented by many hardware media players)
OGG (Free software)

Terminology: Codecs

The specific (digital) format of audio / video data. The codec (COmpresion/DECompression) is the specific algorithm used to turn audio/visual data into digital data and vice versa. As the name "compression" implies, codecs are all about preserving the most quality of the image and sound using the least data (bitrate). Most codecs are "lossy", meaning that the original data is degraded somewhat in order to make the data size small enough for viewing online. Choosing an appropriate bitrate and compressing source material is an important and potentially complex process that can be greatly helped by tools that support sensible "preset" configurations.

Examples:

H.263
H.264
WAV (more or less "raw" uncompressed audio format)
AAC (Advanced Audio Codec)
MP3 (MPEG-1 Audio Level 3)
Theora (Free, typically in OGG)
Vorbis (Free, in OGG & WebM)
VP8 (webm: On2 -- bought by Google in 2010)
Dirac

The State of Codecs

Two camps:

"MPEG": Safari/iOS (Apple), Explorer (Microsoft): MP4 (H.264/AAC)
"Free": (Firefox, Chrome (Google), Opera): OGG (Theora/Vorbis) & WebM (VP8/Vorbis)

Only Chrome is supporting both MP4/3

Flash future for WebM/VP8 ?!

As easy as... (in principle)

<video controls autoplay>
    <source src="video.mp4">
    <source src="video.webm">
    No video support!
</video>

nb iPad "bug" requires mp4 comes first

<audio controls autoplay>
    <source src="audio.mp3">
    <source src="audio.ogg">
    No audio support!
</audio>

Compressing media

firefogg
ffmpeg2theora
HandBrake
ffmpeg
avidemux

@@ Line 16: / Line 16: @@
 == Terminology ==
-=== Container ===
+== Terminology: Container ==
 The container is the "box" that holds the video file. Containers organize how the audio/video data is "laid out" as a "byte stream" (thus may have an impact on how well a video can "stream" or appear in the browser when only partially downloaded). Container formats may also allow for "metadata" to be included (name-value pairs of data such as the artist name of a music track).
@@ Line 29: / Line 29: @@
 * OGG (Free software)
-=== Codecs ===
+== Terminology: Codecs ==
 The specific (digital) format of audio / video data. The codec (COmpresion/DECompression) is the specific algorithm used to turn audio/visual data into digital data and vice versa. As the name "compression" implies, codecs are all about preserving the '''most''' quality of the image and sound using the '''least''' data (bitrate). Most codecs are "lossy", meaning that the original data is degraded somewhat in order to make the data size small enough for viewing online. Choosing an appropriate bitrate and compressing source material is an important and potentially complex process that can be greatly helped by tools that support sensible "preset" configurations.