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Confused about SSDs and encoding video

niuniu

niuniu

macrumors 68020
Original poster
Mar 29, 2009
2,311
1
A man of the people. The right sort of people.
Been lookin around to see if vid encoding is sped up by using an SSD. Seeing lots of contradictory info - is it because the situation depends on whether you are bottlenecked by your processor or not?

I'm on a C2D 2.26 Ghz atm and it takes forever to encode video (around 20 to 25mins per 50minute video). When you have a whole season, or seasons to do.. takes about half a day.
 
The CPU is the bottleneck then, you can check Activity Monitor > Disk Activity during an encoding to see, how fast your HDD is been written to.

I have a 2.8 GHz CPU in my MBP and transcoding a video DVD would be slowed down by the CPU and not the HDD speed (90 MB/s).
If it would be the HDD with 90 MB/s, you would write 5.4 GB per minute, which is probably not the case,
 
simsaladimbamba said:
The CPU is the bottleneck then, you can check Activity Monitor > Disk Activity during an encoding to see, how fast your HDD is been written to.

I have a 2.8 GHz CPU in my MBP and transcoding a video DVD would be slowed down by the CPU and not the HDD speed (90 MB/s).
If it would be the HDD with 90 MB/s, you would write 5.4 GB per minute, which is probably not the case,
Click to expand...

Thanks! It says Peak 2.8MB/sec.. I guess that's quite low? How fast would an i5 or i7 be these days?
 
simsaladimbamba said:
Four to five times faster:
Mac Benchmarks by Geekbench

As you transcode to a highly compressed format, an SSD will not be helping you, if you would transcode to an uncompressed format, HDDs are becoming slow.
Click to expand...

Wow huge increase. Alright thanks, I'll just wait it out for the updates then. Always thought it was an SSD I really wanted, but guess it's a better processor I need after all.
 
A fifty minute video takes a bit less than an hour for me, though I don't do that anymore, but when I had my iBook, it would take 12 hours to transcode one movie via HandBrake.
 
niuniu said:
Handbrake I'm using right this minute. Wonder if some software is faster than others..
Click to expand...

Does Handbrake use all the available CPU? It does on my C2D Macs and Xeon Macs I tested it with. Maybe some application is faster by a minute or three, but that will probably mean a loss in quality.
 
Handbrake seems to operate faster when source/dest file are on my SSD than when they are on my 750gb internal hdd.

As others have said it depends on where your bottleneck is.
 
I did some tests:

I used HandBrake 0.95 (64-bit) for a 5m 00s clip from ripped video DVD using "Normal preset":
2 GHz C2D in 20" iMac from 2007
HandBrake used approx. 150 % of 200 % available CPU power, data rate was around 70 KB/s on average, with a 7 MB spike at the beginning of the process lasting for less than a second.

(1) from external Firewire 800 HDD to internal SSD: 6m 21s

(2) external Firewire 800 HDD to same Firewire 800 HDD: 5m 45s

(3) internal SSD to same SSD: 6m 17s

(4) internal SSD to external Firewire 800 HDD: 5m 46s​

2.8 GHz C2D in 17" MBP from 2009
CPU was used at approx. 150 % of 200 % available CPU power, data rate was around 100 KB/s on average, with a 7 MB spike at the beginning of the process lasting for less than a second.

(1) internal HDD to internal SSD: 4m 08s

(2) internal HDD to internal HDD: 4m 13s

(3) internal SSD to same SSD: 4m 38s

(4) internal SSD to internal HDD: 4m 08s​
 
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