CompuServe Messages

Let me try to explain the block limit issue. You were right in all your assumptions. The Block limit is the maximum size allowable for each frame. This size is set in blocks (disk sectors) of 512 bytes. A limit of 240 means that no frame should be bigger than 122,880 bytes (120k or 240×512). This limit is established by analyzing the hard disk throughput. In order to have a block limit of 240 (or 120k per frame) the hard disk must be able to pump 3.6 megabytes per second (120k x 30). In stills, the limit is fixed at 512 blocks. That means no single frame can be larger than 256k bytes. When an animation is compressed one frame at a time, PARDRV will try to use the best Qfactor allowed. If the resulting size is greater than the block limit, PARDRV will recompress the block using a lower, calculated, Qfactor. This process is dynamic so each frame will have the best possible Qfactor according to its own characteristics. When an animation is recorder directly from live video (through the TBC-IV), there is no time to calculate a different Qfactor for each frame. In this situation, the "busiest" frame in the entire sequence will determine the maximum Qfactor allowed.