OggSpots - Revision history

Saoshyant at 23:27, 15 February 2008

2008-02-15T23:27:01Z

← Older revision		Revision as of 23:27, 15 February 2008
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	npt:00:05:02.000 /my_slides/image_03.png		npt:00:05:02.000 /my_slides/image_03.png
	npt:00:06:50.000 /my_slides/image_04.png		npt:00:06:50.000 /my_slides/image_04.png

			[[Category:Ogg Mappings]]

Martin.leese: /* Purpose */

2008-02-13T21:39:44Z

Purpose

← Older revision		Revision as of 21:39, 13 February 2008
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	Recordings of seminars, lectures and presentations generally consist of slides plus an audio recording of the presentation. Slides are usually (if not animated) just a sequence of images. A very efficient representation of such a recording is as a stream of images with timing information plus the recorded audio underneath.		Recordings of seminars, lectures and presentations generally consist of slides plus an audio recording of the presentation. Slides are usually (if not animated) just a sequence of images. A very efficient representation of such a recording is as a stream of images with timing information plus the recorded audio underneath.

	This specification defines a format to describe a timed image track, including presentation parameters, input image formats and their timing. We encourage in particular the use of ~~<b>PNG</b> as an~~ open [http://www.w3.org/TR/PNG/ ~~image compression format~~] ~~or of <b>JPG<~~/b>.		This specification defines a format to describe a timed image track, including presentation parameters, input image formats and their timing. We encourage in particular the use of the open compression formats [http://www.w3.org/TR/PNG/ PNG] and [http://www.jpeg.org/ JPEG] for lossless and lossy image compression respectively.

	~~We define a logical bitstream format for encapsulating the images inside Ogg~~. ~~When multiplexed together with one of the Xiph audio codecs such as [[Speex~~]~~], [[Vorbis]], [[FLAC]], or [[OggPCM2]], e.g. using [[OggSkeleton]], you end up with a video format that consists of timed images~~ and ~~audio~~.

			We define a logical bitstream format for encapsulating the images inside Ogg. When multiplexed together with one of the Xiph audio codecs such as [[Speex]], [[Vorbis]], [[FLAC]], or [[OggPCM]], e.g. using [[Ogg Skeleton]], you end up with a video format that consists of timed images and audio.

	== Timed Image Specification Format ==		== Timed Image Specification Format ==

Silvia: changed options to include upscaling/downscaling

2006-02-28T11:36:44Z

changed options to include upscaling/downscaling

← Older revision		Revision as of 11:36, 28 February 2006
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	\| Display width \| Display height \| 40-43		\| Display width \| Display height \| 40-43
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| BG-Color \| ~~Rescaling~~ \| Align-Horiz \| Align-Vert \| 44-47		\| BG-Color \| 44-47
			+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			\| Align-Horiz \| Align-Vert \| Options \| 48-51
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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	For transparent images and for smaller, non-rescaled images, the background colour of the images has to be defined. This may be black, white, gray or whatever. This is a default setting which may be overruled by the specific image.		For transparent images and for smaller, non-rescaled images, the background colour of the images has to be defined. This may be black, white, gray or whatever. This is a default setting which may be overruled by the specific image.

	* Rescaling:

	While images that are larger than the display area defined by Display-Width and Display-Height must be scaled down to this size, this may not necessarily be desirable for smaller images. This paramter decides whether smaller images should be scaled up to meet the display size, or just be displayed inside it. This is a default setting may can be ruled over by the specific image through its own parameters.

	* Align-Horizontal, Align-Vertical:		* Align-Horizontal, Align-Vertical:
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	This is a default setting which may be ruled over by the specific image through its own parameters.		This is a default setting which may be ruled over by the specific image through its own parameters.

			* Options:

			* Upscaling: This paramter decides whether smaller images should be scaled up to meet the display size, or just be displayed inside it. This is a default setting and can be ruled over by the specific image through its own parameters.
			* Downscaling: This paramter decides whether larger images should be scaled down to meet the display size, or just be truncated. This is a default setting and can be ruled over by the specific image through its own parameters.

	=== OggSpots data ===		=== OggSpots data ===

Silvia: attempt at putting parameters into images

2006-02-27T05:56:01Z

attempt at putting parameters into images

Show changes

Silvia: alignment

2006-02-27T05:40:42Z

alignment

← Older revision		Revision as of 05:40, 27 February 2006
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	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1\| Byte		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1\| Byte
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Identifier 'SPOTS\0\0\0' \| 0-3		\| Identifier 'SPOTS\0\0\0' \| 0-3
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| \| 4-7		\| \| 4-7
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	The default granule shift used is 32, which halfs the granule position to allow for the backwards pointer.		The default granule shift used is 32, which halfs the granule position to allow for the backwards pointer.


	=== OggSpots data ===		=== OggSpots data ===

Silvia: merged the bos page and the secondary header into one

2006-02-27T05:37:35Z

merged the bos page and the secondary header into one

← Older revision		Revision as of 05:37, 27 February 2006
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	The first step towards encapsulating the data into ogg is the definition of packets:		The first step towards encapsulating the data into ogg is the definition of packets:

	* There is a OggSpots ident header, which is encapsulated in the bos ~~page.~~		* There is a OggSpots ident header with setup parameters, which is encapsulated in the bos page.
	* There is a secondary header packet containing the setup parameters, which is encapsulated in a separate page.
	* Each image is mapped into a data packet, which are each encoded in their own packet and inserted at the accurate time.		* Each image is mapped into a data packet, which are each encoded in their own packet and inserted at the accurate time.
	* The eos page is empty.		* The eos page is empty.
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	\| \| 24-27		\| \| 24-27
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Granuleshift \| 28		\| Granuleshift \| RESERVED FOR LATER USE \| 28-31
	+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| ~~...~~		\| Image-Format \| 32-35
			+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			\| \| 36-39
			+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			\| Display width \| Display height \| 40-43
			+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			\| BG-Color \| Rescaling \| Align-Horiz \| Align-Vert \| 44-47
			+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

	The OggSpots <i>version</i> as described here is major=0 minor=1.		The OggSpots <i>version</i> as described here is major=0 minor=1.
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	The default granule shift used is 32, which halfs the granule position to allow for the backwards pointer.		The default granule shift used is 32, which halfs the granule position to allow for the backwards pointer.


	~~=== OggSpots secondary header ===~~

	~~This header contains all the setup information for the decoder.~~

	~~0 1 2 3~~
	~~0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1\| Byte~~
	~~+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+~~
	~~\| Image-Format \| 0-3~~
	~~+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+~~
	~~\| \| 4-7~~
	~~+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+~~
	~~\| Display width \| Display height \| 8-11~~
	~~+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+~~
	~~\| BG-Color \| Rescaling \| Align-Horiz \| Align-Vert \| 12-15~~
	~~+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+~~

Silvia: move from PNG to generic images

2006-02-21T05:34:53Z

move from PNG to generic images

Show changes

Silvia: OggPNG moved to OggSpots

2006-02-21T05:19:15Z

OggPNG moved to OggSpots

← Older revision		Revision as of 05:19, 21 February 2006
(No difference)

Silvia: deleted authoring bits since unnecessary; added more parameters

2006-02-20T21:06:18Z

deleted authoring bits since unnecessary; added more parameters

@@ Line 10: / Line 10: @@
 == Timed Image Specification Format ==
-An authoring format for specifying "timed images" has to be defined.
+The bitstream format this "codec" should be very simple. It should essentially consist only of a sequence of PNG images preceeded by a header with a simple set o fields to set up the decoding. If at all possible, we're trying to avoid giving parameters to the individual images since this will create an additional intermediate decoding step.
-One option is a plain text format. Something along the lines of:
+The following fields are under discussion:
   Display-Width: 320
   Display-Height: 240
-  [newline]
+  Rescaling: False
   npt:00:00:00.000 /my_slides/image_01.png
   npt:00:02:10.000 /my_slides/image_02.png
   npt:00:05:02.000 /my_slides/image_03.png
   npt:00:06:50.000 /my_slides/image_04.png
@@ Line 46: / Line 56: @@
 * There is a OggPNG ident header, which is encapsulated in the bos page.
-* There is a secondary header packet containing the setup parameters, which is encapsulated in a separage page.
+* There is a secondary header packet containing the setup parameters, which is encapsulated in a separate page.
 * Each image is mapped into a data packet, which are each encoded in their own packet and inserted at the accurate time.
 * The eos page is empty.
@@ Line 89: / Line 99: @@
 === OggPNG secondary header ===
-This header contains all the setup information for the decoder. The following fields are included:
+This header contains all the setup information for the decoder.
                    1                   2                   3

Silvia: inserted further packets

2006-02-19T10:17:57Z

inserted further packets

@@ Line 1: / Line 1: @@
 {{draft}}
 '''PNG''' is an open [http://www.w3.org/TR/PNG/ image compression format] that is used as the basis for a "timed image" codec in this specification. Recordings of seminars, lectures and presentations generally consist of slides and a very efficient representation of such a recording is as a stream of images with timing information plus the recorded audio underneath.
@@ Line 83: / Line 85: @@
 The default granule shift used is 32, which halfs the granule position to allow for the backwards pointer.