I've been using the following command to capture video with ffmpeg for the past two months using my Blackmagic Intensity Pro 4K capture card:
ffmpeg -bm_v210 1 -rtbufsize 1500M -threads 4 -f decklink -i "Intensity Pro 4K@20" -c:a copy -c:v prores -profile:v 1 movie1.mov
This has been fine although occasionally I get a "Decklink input buffer overrun!" error, in which case I have to restart the capture.
However, starting yesterday, I am getting a "Desklink input buffer overrun!" error every time.
[decklink @ 0000000002552cc0] Decklink input buffer overrun!bitrate=479405.2kbits/s speed=0.849x Last message repeated 1 times [decklink @ 0000000002552cc0] Decklink input buffer overrun!bitrate=480001.5kbits/s speed=0.842x Last message repeated 8 times [decklink @ 0000000002552cc0] Decklink input buffer overrun!bitrate=480685.0kbits/s speed=0.842x Last message repeated 15 times
So it looks like my SSD is no longer fast enough to write the data-- but why? It worked fine for the past two months.
I'm capturing onto a Sandisk Extreme Pro SSD (960 GB). The drive only has 10GB of data on it. I manually ran TRIM just a moment ago, but that didn't help. The SanDisk SSD Dashboard shows it has "99%" life remaining.
I have also disabled OneDrive, Dropbox, and all other software I could find that might write to the system during capture.