Anthony Burokas managed to corner Sony’s Juan Martinez at DV Expo and get some detailed technical questions about the PMW-EX1 answered. Questions like, does the EX1 record in 24p mode without additional “pad” frames? I’ve also excerpted a very interesting exchange about how the encoder allocates bitrate below.

> What about the fact that the specifications only indicate two different data
> rates, no lower data rate for the lower frame rate of 24p… Does the
> camcorder then allocate additional bits for each frame to maintain the set
> data rates?

Yes. If you reduce the number of frames, and the data rate is still 35 Mbps, the encoder gives more bits to each 12-frame GOP.
However, if you record bursts of video at 60p, you don’t get less bits per frame. The data going to the card is more than 3x the normal data rate. For instance, if you set the camera to 24p and record at 60p- in essence, overcranking it- then the video bitrate will be 2.5x, the audio will be 2.5x, the error correction, etc, will be that much more. The volume of data going to the card is over 200 Mbps. That’s why we use the SxS cards.

Great questions, and the answers show the level of detail and care that went into engineering this amazing camcorder. Thanks to Anthony for the excellent Q&A!