VirtualDub Turbo I/O

[shekh]

I was playing with direct stream copy (single stream utvideo) and noticed amazing thing: it is incredibly slow.

I looked at preferences and found this:
Disk I/O write mode

"buffered - slowest.." is in fact fastest, about 40fps in my test
"asynchronous fastest.." is slowest, about 10fps
Other options are not interesting.

Can anyone confirm same behavior?

p.s.
found this post (http://www.virtualdub.org/blog/pivot/entry.php?id=31) which sort of explains that everything is difficult

[Groucho2004]

I'm getting the best performance (~110 fps) with "Unbuffered" using a 1080p 20GB UT Video stream from one physical drive to another. Both drives are Velociraptors with a max transfer rate of 200 MB/sec.
I think the bottleneck is mostly HD performance in my case. I'd be curious to see how much faster SSDs would be.

All 4 modes:
Buffered: ~ 65 fps
Write through: ~40 fps
Unbuffered: ~110 fps
Asynchronous: ~100 fps

[raffriff42]

For me asynch/unbuffered is fastest, although both are well over 200fps. (EDIT same as ffmpeg command line)

What is "single stream utvideo"? I was testing with UTVideo+PCM in AVI and the AVIFle input driver.

[Groucho2004]

What is "single stream utvideo"?I suppose a file with just one decoding thread.

[shekh]

What is "single stream utvideo"? I was testing with UTVideo+PCM in AVI and the AVIFle input driver.

In fact it was UTVideo+PCM in AVI but writing only video to destination, so down to metal this is quite simple and I see no reason why it should be slower than simple file copy.
And I was writing to same HDD drive as source (polluted and fragmented).

I know my test is not very accurate but it does not matter with 4x difference in performance.