nobbit
Posts: 121
Joined: Sun Sep 25, 2011 5:51 pm

How fast must my HDD transfer rate be to play HD movies?

Mon Jun 16, 2014 5:56 am

I bought a couple of cheap USB hubs from Hong Kong and their transfer rate is about 24 Mbits/sec. This likely suffices for what I intend to use one for, but a friend asked if she could get the other one to use with her RasPi running XBMC and serving as a media centre.

Would that work? What's the recommended minimum transfer rate for media centre usage?

masterluke
Posts: 200
Joined: Tue Apr 17, 2012 4:10 pm

Re: How fast must my HDD transfer rate be to play HD movies?

Mon Jun 16, 2014 8:26 am

That depends entirely on the bitrate of the video\audio that you are trying to stream. I seem to remember the Pi's USB ports will max out below 24Mbit/s so I think you are safe enough with that drive.

jamesh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 24934
Joined: Sat Jul 30, 2011 7:41 pm

Re: How fast must my HDD transfer rate be to play HD movies?

Mon Jun 16, 2014 8:41 am

A very high quality H264 stream at 1080p30 could get up to 25Mbits/second, but most are much much less than that. You can work it out - if you movie is 2hrs long and is 1GByte in size...

(1*1024*1024*1024*8) / ( 2 * 60 * 60 ) = 1179065 bits/s.
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed. Here's an example...
“I own the world’s worst thesaurus. Not only is it awful, it’s awful."


gkreidl
Posts: 6191
Joined: Thu Jan 26, 2012 1:07 pm
Location: Germany

Re: How fast must my HDD transfer rate be to play HD movies?

Mon Jun 16, 2014 10:14 am

masterluke wrote:That depends entirely on the bitrate of the video\audio that you are trying to stream. I seem to remember the Pi's USB ports will max out below 24Mbit/s so I think you are safe enough with that drive.
I can read around 27 MegaByte/sec. from a HD connected via USB, so this is definitely wrong.
Minimal Kiosk Browser (kweb)
Slim, fast webkit browser with support for audio+video+playlists+youtube+pdf+download
Optional fullscreen kiosk mode and command interface for embedded applications
Includes omxplayerGUI, an X front end for omxplayer

User avatar
GTR2Fan
Posts: 1601
Joined: Sun Feb 23, 2014 9:20 pm
Location: South East UK

Re: How fast must my HDD transfer rate be to play HD movies?

Mon Jun 16, 2014 4:30 pm

Nearly all of my better quality H264 HD movies have peak video bitrates of anywhere between 20 and 60Mbits/s and, for reference, the official total peak AV bitrate for BD Video movies is 48Mbits/s.

Simply going by file size versus duration to calculate bitrate won't work as that only gives you the average bitrate, not the peak. The peak bitrate can often reach 6x the average in CQ-mode, and any decent encoding will almost definitely have been made in CQ-mode.

I suppose the real question is whether the OP means 24Mbits/s or 24MB/s. If it's the latter, then all of the above is irrelevant in this case.
Pi2B Mini-PC/Media Centre: ARM=1GHz (+3), Core=500MHz, v3d=500MHz, h264=333MHz, RAM=DDR2-1200 (+6/+4/+4+schmoo). Sandisk Ultra HC-I 32GB microSD card on '50=100' OCed slot (42MB/s read) running Raspbian/KODI16, Seagate 3.5" 1.5TB HDD mass storage.

Return to “Media centres”