On2 VP4 - Revision history

Kostya: VP4 is pretty much discovered

2021-01-01T11:48:26Z

VP4 is pretty much discovered

← Older revision		Revision as of 04:48, 1 January 2021
Line 124:		Line 124:

	Then macroblock data follows — first full data for luma (4 blocks per MB) and then for chroma (also 4 blocks per MB).		Then macroblock data follows — first full data for luma (4 blocks per MB) and then for chroma (also 4 blocks per MB).
	Macroblock data coding ~~seems to be exactly~~ the same as in VP3.		Macroblock data coding is the same as in VP3.

	=== Interframe data ===		=== Interframe data ===

	First, there's ~~suberblock~~ mode data, it is coded in the same way as in VP3.		First, there's superblock mode data, it is coded in the same way as in VP3.

	Second, there's motion vector data for superblocks. Motion vector data is Huffman coded, each component with a separate context dependent Huffman table.		Second, there's motion vector data for superblocks. Motion vector data is Huffman coded, each component with a separate context dependent Huffman table.
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	[[Category:Video Codecs]]		[[Category:Video Codecs]]
	~~[[Category:Undiscovered Video Codecs]]~~

2016-04-17T13:47:34Z

Interframe data

@@ Line 127: / Line 127: @@
 === Interframe data ===
 [[Category:Video Codecs]]
 [[Category:Undiscovered Video Codecs]]

2016-04-17T12:59:51Z

Intraframe data

← Older revision		Revision as of 05:59, 17 April 2016
Line 117:		Line 117:

	=== Intraframe data ===		=== Intraframe data ===

			* Luma DC Huffman table - 4 bits
			* Luma AC Huffman table - 4 bits
			* Chroma DC Huffman table - 4 bits
			* Chroma AC Huffman table - 4 bits

			Then macroblock data follows — first full data for luma (4 blocks per MB) and then for chroma (also 4 blocks per MB).
			Macroblock data coding seems to be exactly the same as in VP3.

	=== Interframe data ===		=== Interframe data ===

2016-04-17T12:07:20Z

@@ Line 115: / Line 115: @@
      return val + getbits(tail);
+   }
 === Intraframe data ===

2016-04-17T12:06:54Z

Variable-length code

← Older revision		Revision as of 05:06, 17 April 2016
Line 115:		Line 115:
	return val + getbits(tail);		return val + getbits(tail);
	}		}

			=== Intraframe data ===

			=== Interframe data ===

			[[Category:Video Codecs]]
			[[Category:Undiscovered Video Codecs]]

	=== Intraframe data ===		=== Intraframe data ===

2016-04-17T12:06:48Z

Variable-length code

← Older revision		Revision as of 05:06, 17 April 2016
Line 115:		Line 115:
	return val + getbits(tail);		return val + getbits(tail);
	}		}

			=== Intraframe data ===

			=== Interframe data ===

			[[Category:Video Codecs]]
			[[Category:Undiscovered Video Codecs]]

	=== Intraframe data ===		=== Intraframe data ===

2016-04-17T12:06:37Z

Variable-length code

← Older revision		Revision as of 05:06, 17 April 2016
Line 115:		Line 115:
	return val + getbits(tail);		return val + getbits(tail);
	}		}

			=== Intraframe data ===

			=== Interframe data ===

			[[Category:Video Codecs]]
			[[Category:Undiscovered Video Codecs]]

	=== Intraframe data ===		=== Intraframe data ===

2016-04-17T12:06:32Z

Variable-length code

← Older revision		Revision as of 05:06, 17 April 2016
Line 115:		Line 115:
	return val + getbits(tail);		return val + getbits(tail);
	}		}

			=== Intraframe data ===

			=== Interframe data ===

	[[Category:Video Codecs]]		[[Category:Video Codecs]]
	[[Category:Undiscovered Video Codecs]]		[[Category:Undiscovered Video Codecs]]

2016-04-17T12:04:39Z

Display fragments

@@ Line 33: / Line 33: @@
 First there's <code>MBFullyFlags[]</code> coded as flag array.
 Then for all macroblocks that are not fully coded (i.e. <code>MBFullyFlags[mb]</code> is zero) there are flag values in <code>MBCoded[]</code> coded the same way.
-And finally for coded blocks there's some Huffman-coded value.
+And finally for coded blocks there's Huffman-coded CBP:
 ==== Flag arrays coding ====

2016-04-16T17:16:24Z

@@ Line 26: / Line 26: @@
 * ??? - 3 bits
 * ??? - 2 bits
 [[Category:Video Codecs]]
 [[Category:Undiscovered Video Codecs]]