oh no ! Not again… Megabits & MegaBytes

[Matt Geier]

Fernando,

You Write –
ok Megabits per second (mbps) are generally used to describe the speed of an Internet connection, whereas megabytes (MB) usually refer to the size of a file or storage space.

but how can you say that DVCPro Hd (which is 100Mbits/sec) requires 13.9 MBytes/sec to travel on a network ?

Reply –
Both Megabits and Megabytes can be used to describe the speed of a connection since they convert one to another with the math.

DVCPRO HD 1080i50 is a 108Mbit stream size OR ALSO the same as saying 13.5MB stream size.

in terms of a Gigabit Ethernet wire –
The wire itself is able to run at 800mbits/sec or the same as saying 100MB per second. This is the theoretical capacity of a Gigabit Ethernet wire.

When you are on an Apple, using AFP, you’re wire runs about 90MB/sec at full blast if you are using Jumbo Frames. (And assuming you are passing that much MB/sec)

Hopefully this helps.

Regards,

Matt G

[Bob Zelin]

there are countless free charts and calculators available to simply show you what is required for each compression ratio. Personally, I use the Dulce Systems chart, but a very popular FREE calculator which you can download right now from the https://www.aja.com site is
the AJA DATA RATE CALCULATOR application. This tells you exactly the bandwidth that you need.

bob Zelin

[Francois Xavier]

I can’t help to notice that none of them (Dulce or Aja) take the XdCam Hd, in account, (not any flavor of it)

Documentary Director & Editor
Paris /France

[Bob Zelin]

because no one that I know of works in the native XDCam HD codec. AVID editors would use DNxHD. FCP Editors would use ProRes422HQ (or even DVCProHD). I guess if you were a Sony Vegas user, this might be a different case.

Bbo Zelin

[Francois Xavier]

I am a very Fcp person and I don’t like long gop renders ! (who does ?)

it is just that I work fot a Tv facility where XdCam Hd 50 was chosen to be lighter on storage and network. although they shoot Dvc Pro Hd ! would you believe that ?

trying to make them switch to Dvc Pro Hd but they have to change the media port of the Omneon (and the port who does the ingest too) it seems to be expensive

Documentary Director & Editor
Paris /France

[Bob Zelin]

Francois,
there is nothing wrong with the XDCam HD codec, and if you have to deal with the Omneon codec, all of this will work without issue.
It’s still a small codec.

bob Zelin

[Francois Xavier]

there is something Very wrong with the XdCam Codec

Long Gop makes renders and exports vey slow

Documentary Director & Editor
Paris /France

[Fernando Pessoa]

thank you all