TechSmith Screen Capture Codec 2

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	Macroblock slices begin with slice size. If the first byte is odd, then it's the full size. Otherwise read whole 32-bit word and divide it by two in order to obtain real macroblock data size.		Macroblock slices begin with slice size. If the first byte is odd, then it's the full size. Otherwise read whole 32-bit word and divide it by two in order to obtain real macroblock data size.
		+
		+	Macroblocks encode series of 4x4 DCT blocks (4x2), one component after another.
		+
		+	Block format:
		+
		+	DC - 8 bits for the first block, or VLC (for the difference from the previous DC)
		+	number of AC coefficients - VLC
		+	[AC coefficients] - VLC, bottom 4 bits - skip value, top 8 bits - AC value
		+
		+	Scan order is zigzag:
		+
		+	0 2 3 9
		+	1 4 8 10
		+	5 7 11 14
		+	6 12 13 15
		+
		+	IDCT: (TODO)
	[[Category:Video Codecs]]		[[Category:Video Codecs]]
	[[Category:Undiscovered Video Codecs]]		[[Category:Undiscovered Video Codecs]]
	[[Category:Screen Capture Video Codecs]]		[[Category:Screen Capture Video Codecs]]

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Revision as of 19:18, 4 July 2012

• FOURCC: TSC2
• Company: TechSmith

This codec was developed by TechSmith and used in their screen capturing products.

Frame format

This codec operates on 16x8 macroblocks.

 0 - frame type (1- coded, 0 - skip frame)
 1 - luma quantiser?
 2 - chroma quantiser?
 3 - ???
 [macroblock properties]
 [macroblock slices]

Macroblock properties:

 4 bytes LE - chunk size
 rest       - RLE-coded properties in bytes in form (val << 6) | (count)

Macroblock slices begin with slice size. If the first byte is odd, then it's the full size. Otherwise read whole 32-bit word and divide it by two in order to obtain real macroblock data size.

Macroblocks encode series of 4x4 DCT blocks (4x2), one component after another.

Block format:

 DC - 8 bits for the first block, or VLC (for the difference from the previous DC)
 number of AC coefficients - VLC
 [AC coefficients] - VLC, bottom 4 bits - skip value, top 8 bits - AC value

Scan order is zigzag:

 0  2  3  9
 1  4  8 10
 5  7 11 14
 6 12 13 15

IDCT: (TODO)