[FFmpeg-user] Windows 10, ffmpeg concat/demux is slow... part 2

Carlos E. R. robin.listas at telefonica.net
Tue Nov 14 00:19:42 EET 2017

Hash: SHA1

On Monday, 2017-11-13 at 15:56 -0000, Kevin Duffey wrote:

> [quote]
>> As one of the drives
>> is an SSD.. this seems ridiculous to me that it is basically moving at
>> USB2 speeds. At the very least, as it is over a USB 3.1 gen 2, 10Gb/s
>> wire... it should be much much faster than this. So now I am left
>> wondering why my system is super slow at copying files. Is there some
>> configuration in Windows 10 that has to be enabled to allow fast
>> copying?
> I don't know. In the case of the external disk above it seems a hardware
> limitation. Either the disk or the USB3 interface of the disk or the
> computer.
> [/quote]
> ok.. see if the quote thing worked lol.

Perfectly :-)

> So just to be clear, I have been building computers, networks, etc for 
> many years now.. only saying that to ensure that for the most part, I 
> understand the various speeds that USB, SATA, etc should be able to do. 
> Not that anyone was totally questioning that of me, but wanted to throw 
> out there that I do have the knowledge of the basic hardware stuff.  It 
> is in particular with ffmpeg that I am blundering.

But if I remember correctly this computer also has problems with a simple 
concat on the command line:

copy file1.mov + file2.mov fileout.mov

Do this on the same directory, to test a single disk. You can repeat on 
another disk, to try.

> With that in mind, lets assume I had nothing but SSD drives. My laptop 
> has 2 NVMe 960 EVO drives, and one SATA3 SSD. For clarity, it is a SAGER 
> desktop replacement laptop.. not very portable. Also has a 2TB Firecuda 
> SSHD and 64GB RAM with 6700K cpu.

It should be very fast, speciallty the NVMe's. Are they configured in a 
RAID? Is it perhaps degraded?

The SATA3 SSD should also be very fast.

> What sort of speeds should I see when concatting two DNxHR SQ 4K videos 
> together?  That would help me understand better what to expect. I would 
> assume from some other posts I found around the interwebs, that I should 
> see 150fps to 300fps with this process, not what i see now at a paltry 
> 9fps.  If this is a CPU bound task.. the CPU indicates it is using 1% 
> total.. but the disk usage shows at about 20%. So I would assume that I 
> am still not being hampered by disk i/o given that it is not maxed out.

If you can somehow post the source videos somewhere, or other videos with 
the exact same encoding, I can try. In Linux, which is what I use, and 
with more modest hardware.

> I will be building my threadripper system in a couple weeks.. I hope 
> that ffmpeg will benefit from the 16 cores and be much faster... 
> assuming I can get past whatever the issue is with why it is so slow 
> now.

Well, you need finding what the issue is.

- -- 
        Carlos E. R.
        (from openSUSE 42.2 x86_64 "Malachite" at Telcontar)

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