Hi DvInfo users,

I recently bought the BMPCC, and have been enjoying it.

A few questions I havn't been able to find answers to:

-Is there a to check to see if a file has dropped frames after the fact? (Apart from just watching it?)

-Does anyone have experience recording for long periods of time at Prores Lt or Proxy?

-Does anyone who how Prores Proxy would compare to the H264 Codec from the older Canon DLSRs (Like the t3i)?

Thanks!

-Stephen

Does anyone who how Prores Proxy would compare to the H264 Codec from the older Canon DLSRs (Like the t3i)?

According to the ProRes whitepaper, Proxy would have a bitrate of 36 Mbps for 1080p at 24 fps. If I did the math correctly, that would be about a 3.4:1 compression ratio. Assuming the T3i uses a bitrate of 24 Mbps for the same footage, that would be about a 3:1 compression ratio. So compression fairly close.

But the Proxy footage would be 10-bit 4:2:2 (vs the 8-bit 4:2:0 from the T3i). So while it could have more compression artifacts, the color would be much better.

Disclaimer: I don't own either camera; this is just some rough calculations on paper.

I think it might be a mistake to directly compare the two codecs like that.

You generally need at least 2x the data rate with I-frame codecs like ProRes (all flavours) to equal long-gop type compression that I think AVCHD uses.