"HDD" (usb nand pen drive) throughput (tp)

[verbal_666]

Hi all.
Just a simple question, from some tests i did before.

Premise: i know a real HD stream tp in 1080i/p needs also a 10MB/sec (..and more).

VU+Zero: i'm using a real slow hdd pen drive (generic 32GB device, 4MB/sec in write tests), and testing a recording from a HD Channel (Canal+ Sport HD) i see the tp is only 1MB/sec, so my hdd pen drive is enough to manage this recording. Is this low tp given by BH (2.1.4) AVC (h.264) compression, or only because the specific Channel uses high compression (bitrate is about 8k, image is really good at sight)?

Anyway, i was not sure this hdd pen drive could manage an HD recording, but the final result was perfect.

 

[Eragon]

Don't mistake megabits/second with megabytes/second...

AFAIK 1080p sat channels don't yet exist.

 

[verbal_666]

Don't mistake megabits/second with megabytes/second...

I did not. 10MB/sec is for a full stream, i think, not AVC compressed. AVC compressed needs only about 2/4MB/sec, if i remember right. It's this 1MB/sec needed that for me is really low (.. but i like it, obviously ;-)) ... is by real AVC/h.264 compression by Channel or is BH that does the trick?

AFAIK 1080p sat channels don't yet exist.

I know. It's only theory. Stay in 1080i, but talk also of future 1080p ;-)

 

[Eragon]

Sat channel streams are expressed in megabits/sec
Storage transfer rate in megabytes/sec...

 

[verbal_666]

Ok, perfect.
So, a real HD stream needs "only" 10Mbit ( /8 = 1MB/sec about) of tp? In media.
And so, a slow nand drive with 4MB/sec tp is really enough?

Does (will ) 1080p doubles values?

 

[verbal_666]

So, does this tp test is right for an AVC/compressed stream?

8 Mbit sec average
1 MB sec average
60 MB min average
3600 MB hour average
3,6 GB hour average

Will future 1080p stream double the values?

16 Mbit sec average
2 MB sec average
120 MB min average
7200 MB hour average
7,2 GB hour average

 

[Eragon]

Correct.
Please consider that however an actual 1080i DVB-S2 channel rarely exceeds 4-5 Mb/s