Capturing problems: speed fluctuates

[Oaktown]

What kind of drive are you using with your AVerMedia box? If you're using a regular USB3 HDD mechanical drive, it's very possible your drive is not fast enough to record all the frames and you've got a bunch of dropped frames in there.

Use the Blackmagic Disk Speed Test tool to figure out what's the recording capacity of your drive.

Also, here is the list of your devices' supported resolutions:

so to avoid any kind of internal conversion, I would set the resolution to 1080i50/60 assuming your drive is fast enough to record all the frames.

[zenovdb]

thanks!
I'm using a USB drive, will check if that's fast enough!

[Oaktown]

That's more than likely than not your problem. Most USB drives are equipped with a 5400rpm HDD and they are not fast enough to record HD video so your AVerMedia recorder is dropping so many frames the final recording is significantly and noticeably shorter.

My advice is to purchase an SSD drive and install it in your recorder as an internal drive. See page 21 of the manual for instructions on how-to.

[zenovdb]

actually it's a USB stick, how does that compare in speed to SSD's or HDD's?

[Oaktown]

All USB sticks have different I/O speeds so it's hard to tell but they're typically pretty slow in Write mode. The only way to know what your stick can do is run it through the Blackmagic Disk Speed Test which is available on both Mac & PC.

I'm assuming you'll want 10-bit recording so so give you a sense, here are some typical data rate from this Wikipedia article on uncompressed video and I would allow for at 20% headroom to be safe :

720p HDTV uncompressed
8-bit @ 1280x720 @ 59.94 fps = 105 MB/s, or 370 GB/h.
10-bit @ 1280x720 @ 59.94 fps = 140 MB/s, or 494 GB/h.

1080i and 1080p HDTV uncompressed
8-bit @ 1920x1080 @ 24 fps = 95 MB/s, or 334 GB/h.
10-bit @ 1920x1080 @ 24 fps = 127 MB/s, or 445 GB/h.
8-bit @ 1920x1080 @ 25 fps = 99 MB/s, or 348 GB/h.
10-bit @ 1920x1080 @ 25 fps = 132 MB/s, or 463 GB/h.
8-bit @ 1920x1080 @ 29.97 fps = 119 MB/s, or 417 GB/h.
10-bit @ 1920x1080 @ 29.97 fps = 158 MB/s, or 556 GB/h.

1080i and 1080p HDTV RGB (4:4:4) uncompressed
10-bit @ 1280x720p @ 60 fps = 211 MB/s, or 742 GB/h.
10-bit @ 1920x1080 @ 24 fps = 190 MB/s, or 667 GB/h.
10-bit @ 1920x1080 @ 50i = 198 MB/s, or 695 GB/h.
10-bit @ 1920x1080 @ 60i = 237 MB/s, or 834 GB/h.720p HDTV uncompressed
8-bit @ 1280x720 @ 59.94 fps = 105 MB/s, or 370 GB/h.
10-bit @ 1280x720 @ 59.94 fps = 140 MB/s, or 494 GB/h.

1080i and 1080p HDTV uncompressed
8-bit @ 1920x1080 @ 24 fps = 95 MB/s, or 334 GB/h.
10-bit @ 1920x1080 @ 24 fps = 127 MB/s, or 445 GB/h.
8-bit @ 1920x1080 @ 25 fps = 99 MB/s, or 348 GB/h.
10-bit @ 1920x1080 @ 25 fps = 132 MB/s, or 463 GB/h.
8-bit @ 1920x1080 @ 29.97 fps = 119 MB/s, or 417 GB/h.
10-bit @ 1920x1080 @ 29.97 fps = 158 MB/s, or 556 GB/h.

1080i and 1080p HDTV RGB (4:4:4) uncompressed
10-bit @ 1280x720p @ 60 fps = 211 MB/s, or 742 GB/h.
10-bit @ 1920x1080 @ 24 fps = 190 MB/s, or 667 GB/h.
10-bit @ 1920x1080 @ 50i = 198 MB/s, or 695 GB/h.
10-bit @ 1920x1080 @ 60i = 237 MB/s, or 834 GB/h.

[zenovdb]

thanks for the help Oaktown!
I guess this is the problem, the usb-stick is nowhere near fast enough..I will have to try an SSD.