MJPEG Codec for HDV

[Margus Voll]

Hi.

For greenscreen mjpg should be better as i underestand mjpg is 4:2:2 as hdv is only 4:2:0 etc.

—

Margus

https://iconstudios.eu

[Callum Mclay]

HI Dave

For editing purposes, you should have an easier time editing with the MJPEG codec rather than HDV. The MJPEG codec is intra-frame coded only, whereas HDV is MPEG 2 based, and has temporal redundancy encoding, making it more difficult to edit.

With that said, modern editing machines can handle HDV editing reasonably well, but you will still experience problems for frame accurate cutting, due to the long GOP format of HDV. The MJPEG codec does not have the ability to be scaled, and will stay at the target data rate of around 12 to 15 MB per second.

And as correctly stated above, HDV is still DV encoding, and so has 4:2:0 colour subsampling, whereas MJPEG has 4:2:2, and so you will retain more colour information for your chroma key work.

Callum McLay
Technical Support Consultant
Blackmagic Design EMEA

[Dave Evans]

Thanks for taking time to reply Margus & Callum.

May I ask some further questions. How well does the codec play with other applications such as Boris FX, After FX, Procoder 3 for example.
And how well does it scale when downconverting for SD DVD.

Thanks for your help, Dave.

[Margus Voll]

Hi again.

4:2:2 scales better as there is more data as you know but generally it is more up to software like in premiere resize might be bad but for instance in combustion resize is class of its own.

So generally it is not so much up in the format specially in downscale.

SO try to test out stuff what you feel works best … as in render time etc. Generally as i see mjpg is like uncompressed with its 422 but it ads a layer of extra work on your machine.

Just test it out make different compression files resize them etc.
Regular R & D to work flow developement.

—

Margus

https://iconstudios.eu

[Dave Evans]

Thanks for the reply Margus.

Just trying to get some info before we decide to take a look at this option.

Are you running CS3 with this card? Is it a stable option?

Regards

Dave.

[Martin Vincent]

Its not necessarily extra work, first its not lossless second as its a compressed format it takes a little cpu on the BM card so no problem there, and at last it reduce the bandwidth needed from hard drives a lot so you can capture without a big fat raid 0 or 5 backing up. So its good when you don’t have enough drive space or bandwidth on the drives when using multilayer video in HD 4:2:2 its almost unavoidable.

[Dave Evans]

Thanks for the comments Martin.

Does this work well for you in CS3 are the any things to look out for.

Regards Dave.

[Margus Voll]

Hi.

In technical point ofcourse it is not lossless but for applications it is something like that compared to hdv and mpg2.

I’d say even digibeta might give you some compression on its 2 to 1 ratio.

—

Margus

https://iconstudios.eu

[Callum Mclay]

HI Dave

Blackmagic Design currently have full compatibility with Adobe CS3 including Premiere Pro, After Effects and Photoshop.

So you should have a nice stable workflow using Motion JPEG with Premiere CS 3, and the latest Blackmagic Drivers. Please bear in mind that MJPEG as a codec is more CPU intensive than an uncompressed workflow, but much less disk intensive, allowing you to get away with HD Resolution without the need for a hard drive array.

Callum McLay
Technical Support Consultant
Blackmagic Design EMEA