TechSmith Screen Capture Codec 2: Difference between revisions
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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]] | ||
Revision as of 12:18, 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)