Record Time Doesn't Change Between 1080 and 720.

HowdyDoo

HowdyDoo

Well-known member
Why doesn't the amount of record time change when I switch from 720 to 1080 on the EX1 like it does on the HVX? On an 8GB card, I get 25 minutes of record time in both 780HQ and 1080HQ? This also happens when I change frame rates. The record time stays the same.
 
I can't say for sure, but if I were to guess, I would say it's because the XDCAM EX codec has a constant 35mbps bit rate. The amount of bandwith used by the video wouldn't change with a lower resolution.
 
XDCam EX is a variable bit rate codec, but it's 35mbps nominal. So at 720p you have more bandwidth available.
 
:) I think they kept the 35mbps to provided more bandwith for 720p for the overcrank feature (slow motion). As you know 1080p is limited to mostly undercranking. Therefore, Sony decided to keep things simple by locking all 720h resolution in 35mbps. -- carl
 
Okay. That makes sense. Perhaps you can answer my second question.

Why doesn't the record time change when switching between 24 and 30p like it does with the HVX?
 
HowdyDoo said:
Okay. That makes sense. Perhaps you can answer my second question.

Why doesn't the record time change when switching between 24 and 30p like it does with the HVX?
Click to expand...

For the exact same reasons mentioned above.

When you switch to HQ mode, all of the HQ formats regardless of frame rate all record at 35mbps; therefore, they all take the same amount of record time.

Having said that, technically 24P would yield a better image than 30P. This is due to the same datarate (35mbps) only has to represent 24 frames as opposed to 30.
Now if you can actually see a difference, that's another story.
 
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