CVD subtitles - Revision history

DoesItReallyMatter: Wikipedia says CVDs are closely related to SVCDs

2019-02-23T06:39:01Z

Wikipedia says CVDs are closely related to SVCDs

← Older revision		Revision as of 06:39, 23 February 2019
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	'''CVD''' ~~is a~~ [[subtitle]] format.		'''CVD subtitles''' are [[subtitle]]s for CVDs (China Video Discs), a disc format closely related to [[SVCD]]s (Super Video CDs).

	A technical description is avaliable from the websites below:		A technical description is avaliable from the websites below:
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	* [http://www.videohelp.com/forum/userguides/98177.php CVD (China Video Disc) Introduction and comparison to similar formats (videohelp.com)]		* [http://www.videohelp.com/forum/userguides/98177.php CVD (China Video Disc) Introduction and comparison to similar formats (videohelp.com)]

	~~[[Category:Physical media]]~~
	[[Category:Subtitles]]		[[Category:Subtitles]]

DoesItReallyMatter: DoesItReallyMatter moved page CVD to CVD subtitles: CVD is the disc itself

2019-02-23T06:31:36Z

DoesItReallyMatter moved page CVD to CVD subtitles: CVD is the disc itself

← Older revision	Revision as of 06:31, 23 February 2019
(No difference)

DoesItReallyMatter: +:Category:Physical media

2019-02-23T06:19:06Z

+Category:Physical media

← Older revision		Revision as of 06:19, 23 February 2019
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	* [http://www.videohelp.com/forum/userguides/98177.php CVD (China Video Disc) Introduction and comparison to similar formats (videohelp.com)]		* [http://www.videohelp.com/forum/userguides/98177.php CVD (China Video Disc) Introduction and comparison to similar formats (videohelp.com)]

			[[Category:Physical media]]
	[[Category:Subtitles]]		[[Category:Subtitles]]

H2g2bob: cat

2007-03-12T18:41:35Z

cat

← Older revision		Revision as of 18:41, 12 March 2007
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	* [http://www.vcdimager.org/pub/vcdimager/manuals/0.7/cvd-subtitles.html CVD (Chaoji VCD) Subtitles Technical Description (vcdimager.org)]		* [http://www.vcdimager.org/pub/vcdimager/manuals/0.7/cvd-subtitles.html CVD (Chaoji VCD) Subtitles Technical Description (vcdimager.org)]
	* [http://www.videohelp.com/forum/userguides/98177.php CVD (China Video Disc) Introduction and comparison to similar formats (videohelp.com)]		* [http://www.videohelp.com/forum/userguides/98177.php CVD (China Video Disc) Introduction and comparison to similar formats (videohelp.com)]

			[[Category:Subtitles]]

H2g2bob at 12:27, 27 February 2006

2006-02-27T12:27:00Z

← Older revision		Revision as of 12:27, 27 February 2006
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	A technical description is avaliable from the websites below:		A technical description is avaliable from the websites below:
	* [http://www.vcdimager.org/pub/vcdimager/manuals/0.7/cvd-subtitles.html CVD (Chaoji VCD) ~~Subtitle Information~~]		* [http://www.vcdimager.org/pub/vcdimager/manuals/0.7/cvd-subtitles.html CVD (Chaoji VCD) Subtitles Technical Description (vcdimager.org)]
			* [http://www.videohelp.com/forum/userguides/98177.php CVD (China Video Disc) Introduction and comparison to similar formats (videohelp.com)]

H2g2bob at 23:31, 11 February 2006

2006-02-11T23:31:13Z

← Older revision		Revision as of 23:31, 11 February 2006
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	[http://www.vcdimager.org/pub/vcdimager/manuals/0.7/cvd-subtitles.html CVD (Chaoji VCD) Subtitle Information]		'''CVD''' is a [[subtitle]] format.

			A technical description is avaliable from the websites below:
			* [http://www.vcdimager.org/pub/vcdimager/manuals/0.7/cvd-subtitles.html CVD (Chaoji VCD) Subtitle Information]

Rocky: Link to existing info rather than recreate anew.

2006-02-07T03:18:35Z

Link to existing info rather than recreate anew.

← Older revision		Revision as of 03:18, 7 February 2006
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	~~The following information is culled by Rocky Bernstein from information provided by Julio Sanchez Fernandez in~~ [http://~~subhandler~~.~~sourceforge~~.~~net http:~~//~~subhandler.sourceforge.net]~~		[http://www.vcdimager.org/pub/vcdimager/manuals/0.7/cvd-subtitles.html CVD (Chaoji VCD) Subtitle Information]

	We do not have information on the subtitle format used on CVD's except the submux sample code and a couple of samples of dubious origin. Thus, the information below is result of reading some code whose correctness is not known and some experimentation.

	~~CVD subtitles are different in several ways from [[OGT\|SVCD OGT]] subtitles.~~

	The image data comes first and meta data is at the end. So that the metadata can be found easily, the subtitle packet starts with two bytes (everything is big-endian again) that the image data comes interlaced and is run-length encoded (RLE). Each field is a four-bit nibbles that is further subdivided in a two-bit repeat count and a two-bit color number - up to three pixels can be described in four bits. What a 0 ~~repeat count means not known~~. It
	might be used for RLE extension. There is a special case of a 0 repeat count that has been inferred: when the full nibble is zero, the rest of the line is filled with the color value in the next nibble. It is unknown what happens if the color value is greater than three.
	~~The rest seems to use a 4~~-~~entries palette~~. ~~It is possible that the fill-line general case above is not as described and the zero repeat count means fill line. But since this hasn't been ever seen, the preceding is only conjecture.~~

	~~Here is information given at the start of a subtitle:~~

	* SPU size 2 bytes
	* metadata offset 2 bytes

	Although metadata information does come in a fixed field order, every metadata field consists of a tag byte followed by parameters. In all cases seen, the size including the tag byte is exactly four bytes.

	{\|
	~~! code !! Meaning~~
	\|-
	~~\| 0x0c \|\|Unknown~~
	\|-
	~~\| 0x04 \|\| 24-bit subtitle duration in 1/90000ths of a second~~
	\|-
	~~\| 0x17 \|\|upper left x, y position, each a 10-bit value, encoded:~~
	~~x = (~~(~~p[1]&0x0f~~)~~<<6) + (p[2]>>2)~~
	~~y = ((p[2~~]~~&0x03)<<8) + p[3];~~
	\|-
	~~\| 0x1f \|\| lower right x, y position, each a 10-bit (0-1023) value, encoded as above~~
	\|-
	~~\| 0x24 \|\| 3 bytes primary palette 0 - 1 byte for each of y, u, and v~~
	\|-
	~~\| 0x25 \|\| 3 bytes primary palette 1 - 1 byte for each of y, u, and v~~
	\|-
	~~\| 0x26 \|\| 3 bytes primary palette 2 - 1 byte for each of y, u, and v~~
	\|-
	~~\| 0x27 \|\| 3 bytes primary palette 3 - 1 byte for each of y, u, and v~~
	\|-
	~~\| 0x2c \|\| 3 bytes highlight palette 0 - 1 byte for each of y, u, and v~~
	\|-
	~~\| 0x2d \|\| 3 bytes highlight palette 1 - 1 byte for each of y, u, and v~~
	\|-
	~~\| 0x2e \|\| 3 bytes highlight palette 2 - 1 byte for each of y, u, and v~~
	\|-
	~~\| 0x2f \|\| 3 bytes highlight palette 3 - 1 byte for each of y, u, and v~~
	\|-
	~~\| 0x37 \|\| 3 bytes transparency for primary palette - 1 byte for each of y, u and v~~
	\|-
	~~\| 0x3f \|\| 3 bytes transparency for highlight palette - 1 byte for each of y, u and v~~
	\|-
	~~\| 0x47 \|\| Offset to start of even rows of interlaced image.~~
	\|-
	~~\| 0x4f \|\| Offset to start of odd rows of interlaced image.~~
	\|}

Rocky: Document the CVD subtitle format

2006-02-06T13:25:07Z

Document the CVD subtitle format

New page

The following information is culled by Rocky Bernstein from information provided by Julio Sanchez Fernandez in [http://subhandler.sourceforge.net http://subhandler.sourceforge.net]

We do not have information on the subtitle format used on CVD's except the submux sample code and a couple of samples of dubious origin. Thus, the information below is result of reading some code whose correctness is not known and some experimentation.

CVD subtitles are different in several ways from [[OGT|SVCD OGT]] subtitles.

The image data comes first and meta data is at the end. So that the metadata can be found easily, the subtitle packet starts with two bytes (everything is big-endian again) that the image data comes interlaced and is run-length encoded (RLE). Each field is a four-bit nibbles that is further subdivided in a two-bit repeat count and a two-bit color number - up to three pixels can be described in four bits. What a 0 repeat count means not known. It
might be used for RLE extension. There is a special case of a 0 repeat count that has been inferred: when the full nibble is zero, the rest of the line is filled with the color value in the next nibble. It is unknown what happens if the color value is greater than three.
The rest seems to use a 4-entries palette. It is possible that the fill-line general case above is not as described and the zero repeat count means fill line. But since this hasn't been ever seen, the preceding is only conjecture.

Here is information given at the start of a subtitle:

* SPU size 2 bytes
* metadata offset 2 bytes

Although metadata information does come in a fixed field order, every metadata field consists of a tag byte followed by parameters. In all cases seen, the size including the tag byte is exactly four bytes.

{|
! code !! Meaning
|-
| 0x0c ||Unknown
|-
| 0x04 || 24-bit subtitle duration in 1/90000ths of a second
|-
| 0x17 ||upper left x, y position, each a 10-bit value, encoded:
x = ((p[1]&0x0f)<<6) + (p[2]>>2)
y = ((p[2]&0x03)<<8) + p[3];
|-
| 0x1f || lower right x, y position, each a 10-bit (0-1023) value, encoded as above
|-
| 0x24 || 3 bytes primary palette 0 - 1 byte for each of y, u, and v
|-
| 0x25 || 3 bytes primary palette 1 - 1 byte for each of y, u, and v
|-
| 0x26 || 3 bytes primary palette 2 - 1 byte for each of y, u, and v
|-
| 0x27 || 3 bytes primary palette 3 - 1 byte for each of y, u, and v
|-
| 0x2c || 3 bytes highlight palette 0 - 1 byte for each of y, u, and v
|-
| 0x2d || 3 bytes highlight palette 1 - 1 byte for each of y, u, and v
|-
| 0x2e || 3 bytes highlight palette 2 - 1 byte for each of y, u, and v
|-
| 0x2f || 3 bytes highlight palette 3 - 1 byte for each of y, u, and v
|-
| 0x37 || 3 bytes transparency for primary palette - 1 byte for each of y, u and v
|-
| 0x3f || 3 bytes transparency for highlight palette - 1 byte for each of y, u and v
|-
| 0x47 || Offset to start of even rows of interlaced image.
|-
| 0x4f || Offset to start of odd rows of interlaced image.
|}