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H.261
Overview
H.261 is a standard video-conferencing codec. As such, it
is optimized for low data rates and relatively low motion.
Architectures Supported
Pros
- H.261 is optimized for low data rates.
Cons
- Not generally as good quality as H.263.
- H.261 is CPU intensive, so data rates higher than 50 KBps may
bog down most machines.
- It may not play well on lower-end machines.
Tips
- H.261 has a strong temporal compression component, and works best on
movies in which there is little change between frames.
| Ideal source material |
Low-motion video |
| Supported bit depths |
16-bit color |
| Compression time |
Symmetrical, realtime |
| Temporal compression? |
Yes |
| Special features |
- |
| Encoder requirements |
Any MacOS or Windows |
| Decoder requirements |
PowerMac or Pentium |
| Encoder availability |
Built into QT Conferencing kit |
| Decoder availability |
Built into QT Conferencing kit |
| Algorithm |
Discrete Cosine Transform (DCT) with Motion Compensation
(H.261 was the first video codec based on DCT) |
| Manufacturer |
Many, including Apple and Microsoft |
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